Cygwin cleanup

From 174cc603ff951b86794f57fcc8c7d326d948e006 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH] WIP CI support for Cygwin.

ci-os-only: cygwin, xindows, xinux

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed

XXX I have no idea if crash dump works, and if this should share
elements with the msys work in commitfest #3575
---
 .cirrus.yml                                   | 59 +++++++++++++++++++
 configure                                     | 18 +++---
 configure.ac                                  |  6 +-
 src/interfaces/libpq/t/001_uri.pl             | 11 +++-
 src/interfaces/libpq/t/002_api.pl             | 13 +++-
 .../libpq_pipeline/t/001_libpq_pipeline.pl    | 14 ++++-
 src/test/perl/PostgreSQL/Test/Cluster.pm      |  2 +-
 src/test/perl/PostgreSQL/Test/Utils.pm        | 12 +++-
 src/tools/ci/cores_backtrace.sh               |  6 +-
 9 files changed, 120 insertions(+), 21 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index f23d6cae552..0389b7758d1 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -456,6 +456,65 @@ task:
       path: "crashlog-*.txt"
       type: text/plain
 
+task:
+  name: Windows - Cygwin
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: 4
+    TEST_JOBS: 3
+    CCACHE_DIR: /tmp/ccache
+    CCACHE_LOGFILE: ccache.log
+    CONFIGURE_FLAGS: --enable-cassert --enable-debug --enable-tap-tests --with-ldap --with-ssl=openssl --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+
+  only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+
+  windows_container:
+    image: cirrusci/windowsservercore:2019
+    os_version: 2019
+    cpu: $CPUS
+    memory: 4G
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+
+  setup_additional_packages_script: |
+    choco install  --cache C:\tools\cygwin\choco -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libssl-devel,libkrb5-devel,openldap-devel,libreadline-devel,perl,perl-IPC-Run
+    C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y" || EXIT /b 1
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf" || EXIT /b 1
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf" || EXIT /b 1
+    C:\tools\cygwin\bin\bash.exe --login -c "net start cygserver" || EXIT /b 1
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    C:\tools\cygwin\bin\bash.exe --login -c "id; uname -a; ulimit -a -H; ulimit -a -S; export" || EXIT /b 1
+
+  configure_script:
+    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
+    - C:\tools\cygwin\bin\bash.exe --login -xc "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done" || EXIT /b 1
+
+  build_script:
+    - C:\tools\cygwin\bin\bash.exe --login -xc "ccache --zero-stats" || EXIT /b 1
+    - C:\tools\cygwin\bin\bash.exe --login -xc "cd '%cd%' && make -s -j '%BUILD_JOBS%' world-bin" || EXIT /b 1
+    - C:\tools\cygwin\bin\bash.exe --login -xc "ccache --show-stats" || EXIT /b 1
+
+  always:
+    upload_caches: ccache
+
+  test_world_script:
+    - C:\tools\cygwin\bin\bash.exe --login -xc "cd '%cd%' && timeout 33m make -s -j '%TEST_JOBS%' check-world -Otarget" || EXIT /b 1
+
+  on_failure:
+    <<: *on_failure
+    cores_script:
+      - C:\tools\cygwin\bin\bash.exe --login -xc "cd '%cd%' && src/tools/ci/cores_backtrace.sh linux ." || EXIT /b 1
+
 
 task:
   name: CompilerWarnings
diff --git a/configure b/configure
index c5bc3823958..8c6ca4381fb 100755
--- a/configure
+++ b/configure
@@ -5675,15 +5675,15 @@ fi
 
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CC} supports -Wimplicit-fallthrough=3, for CFLAGS" >&5
-$as_echo_n "checking whether ${CC} supports -Wimplicit-fallthrough=3, for CFLAGS... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CC} supports -Wimplicit-fallthrough 3, for CFLAGS" >&5
+$as_echo_n "checking whether ${CC} supports -Wimplicit-fallthrough 3, for CFLAGS... " >&6; }
 if ${pgac_cv_prog_CC_cflags__Wimplicit_fallthrough_3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   pgac_save_CFLAGS=$CFLAGS
 pgac_save_CC=$CC
 CC=${CC}
-CFLAGS="${CFLAGS} -Wimplicit-fallthrough=3"
+CFLAGS="${CFLAGS} -Wimplicit-fallthrough 3"
 ac_save_c_werror_flag=$ac_c_werror_flag
 ac_c_werror_flag=yes
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -5710,19 +5710,19 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_prog_CC_cflags__Wimplicit_fallthrough_3" >&5
 $as_echo "$pgac_cv_prog_CC_cflags__Wimplicit_fallthrough_3" >&6; }
 if test x"$pgac_cv_prog_CC_cflags__Wimplicit_fallthrough_3" = x"yes"; then
-  CFLAGS="${CFLAGS} -Wimplicit-fallthrough=3"
+  CFLAGS="${CFLAGS} -Wimplicit-fallthrough 3"
 fi
 
 
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CXX} supports -Wimplicit-fallthrough=3, for CXXFLAGS" >&5
-$as_echo_n "checking whether ${CXX} supports -Wimplicit-fallthrough=3, for CXXFLAGS... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CXX} supports -Wimplicit-fallthrough 3, for CXXFLAGS" >&5
+$as_echo_n "checking whether ${CXX} supports -Wimplicit-fallthrough 3, for CXXFLAGS... " >&6; }
 if ${pgac_cv_prog_CXX_cxxflags__Wimplicit_fallthrough_3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   pgac_save_CXXFLAGS=$CXXFLAGS
 pgac_save_CXX=$CXX
 CXX=${CXX}
-CXXFLAGS="${CXXFLAGS} -Wimplicit-fallthrough=3"
+CXXFLAGS="${CXXFLAGS} -Wimplicit-fallthrough 3"
 ac_save_cxx_werror_flag=$ac_cxx_werror_flag
 ac_cxx_werror_flag=yes
 ac_ext=cpp
@@ -5761,7 +5761,7 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_prog_CXX_cxxflags__Wimplicit_fallthrough_3" >&5
 $as_echo "$pgac_cv_prog_CXX_cxxflags__Wimplicit_fallthrough_3" >&6; }
 if test x"$pgac_cv_prog_CXX_cxxflags__Wimplicit_fallthrough_3" = x"yes"; then
-  CXXFLAGS="${CXXFLAGS} -Wimplicit-fallthrough=3"
+  CXXFLAGS="${CXXFLAGS} -Wimplicit-fallthrough 3"
 fi
 
 
@@ -17000,7 +17000,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o test "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index 61d0dd5d586..2be0cae8784 100644
--- a/configure.ac
+++ b/configure.ac
@@ -504,8 +504,8 @@ if test "$GCC" = yes -a "$ICC" = no; then
   PGAC_PROG_CXX_CFLAGS_OPT([-Wendif-labels])
   PGAC_PROG_CC_CFLAGS_OPT([-Wmissing-format-attribute])
   PGAC_PROG_CXX_CFLAGS_OPT([-Wmissing-format-attribute])
-  PGAC_PROG_CC_CFLAGS_OPT([-Wimplicit-fallthrough=3])
-  PGAC_PROG_CXX_CFLAGS_OPT([-Wimplicit-fallthrough=3])
+  PGAC_PROG_CC_CFLAGS_OPT([-Wimplicit-fallthrough 3])
+  PGAC_PROG_CXX_CFLAGS_OPT([-Wimplicit-fallthrough 3])
   PGAC_PROG_CC_CFLAGS_OPT([-Wcast-function-type])
   PGAC_PROG_CXX_CFLAGS_OPT([-Wcast-function-type])
   # This was included in -Wall/-Wformat in older GCC versions
@@ -1947,7 +1947,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o test "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/interfaces/libpq/t/001_uri.pl b/src/interfaces/libpq/t/001_uri.pl
index beaf13b49ca..c46aeb71853 100644
--- a/src/interfaces/libpq/t/001_uri.pl
+++ b/src/interfaces/libpq/t/001_uri.pl
@@ -224,7 +224,16 @@ sub test_uri
 
 	$expect{'exit'} = $expect{stderr} eq '';
 
-	my $cmd = [ 'libpq_uri_regress', $uri ];
+	my $cmd;
+	if (-e "$ENV{'TESTDIR'}/test/libpq_uri_regress.exe")
+	{
+		$cmd = [ "$ENV{'TESTDIR'}/test/libpq_uri_regress.exe", $uri ];
+	}
+	else
+	{
+		$cmd = [ 'libpq_uri_regress', $uri ];
+	}
+
 	$result{exit} = IPC::Run::run $cmd, '>', \$result{stdout}, '2>',
 	  \$result{stderr};
 
diff --git a/src/interfaces/libpq/t/002_api.pl b/src/interfaces/libpq/t/002_api.pl
index fa00221ae29..3bf89e85823 100644
--- a/src/interfaces/libpq/t/002_api.pl
+++ b/src/interfaces/libpq/t/002_api.pl
@@ -6,7 +6,18 @@ use PostgreSQL::Test::Utils;
 use Test::More;
 
 # Test PQsslAttribute(NULL, "library")
-my ($out, $err) = run_command([ 'libpq_testclient', '--ssl' ]);
+
+my $cmd;
+if (-e "$ENV{'TESTDIR'}/test/libpq_uri_regress.exe")
+{
+        $cmd = "$ENV{'TESTDIR'}/test/libpq_testclient.exe";
+}
+else
+{
+        $cmd = 'libpq_testclient'
+}
+
+my ($out, $err) = run_command([ $cmd, '--ssl' ]);
 
 if ($ENV{with_ssl} eq 'openssl')
 {
diff --git a/src/test/modules/libpq_pipeline/t/001_libpq_pipeline.pl b/src/test/modules/libpq_pipeline/t/001_libpq_pipeline.pl
index 0821329c8d3..126cd7a0085 100644
--- a/src/test/modules/libpq_pipeline/t/001_libpq_pipeline.pl
+++ b/src/test/modules/libpq_pipeline/t/001_libpq_pipeline.pl
@@ -14,7 +14,17 @@ $node->start;
 
 my $numrows = 700;
 
-my ($out, $err) = run_command([ 'libpq_pipeline', 'tests' ]);
+my $libpq_pipeline;
+if (-e "libpq_pipeline.exe")
+{
+	$libpq_pipeline = "libpq_pipeline.exe";
+}
+else
+{
+	$libpq_pipeline = "libpq_pipeline";
+}
+
+my ($out, $err) = run_command([ $libpq_pipeline, 'tests' ]);
 die "oops: $err" unless $err eq '';
 my @tests = split(/\s+/, $out);
 
@@ -39,7 +49,7 @@ for my $testname (@tests)
 	# Execute the test
 	$node->command_ok(
 		[
-			'libpq_pipeline', @extraargs,
+			$libpq_pipeline, @extraargs,
 			$testname,        $node->connstr('postgres')
 		],
 		"libpq_pipeline $testname");
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index c8c7bc5045a..febf5988434 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -827,7 +827,7 @@ sub start
 	# compatibility with older versions.
 	$ret = PostgreSQL::Test::Utils::system_log(
 		'pg_ctl', '-w',           '-D', $self->data_dir,
-		'-l',     $self->logfile, '-o', "--cluster-name=$name",
+		'-l',     $self->logfile, '-o', "-c cluster-name=$name",
 		'start');
 
 	if ($ret != 0)
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 1ca2cc59170..f10ef55de9a 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys'
+	  || $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..475dd609a22 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,8 @@
 #! /bin/sh
 
+#set -e
+set -x
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -18,7 +21,7 @@ case $os in
 esac
 
 first=1
-for corefile in $(find "$directory" -type f) ; do
+for corefile in $(find "$directory" -type f \( -name 'core.*' -o -name core \) ) ; do
     if [ "$first" -eq 1 ]; then
         first=0
     else
@@ -30,6 +33,7 @@ for corefile in $(find "$directory" -type f) ; do
         lldb -c $corefile --batch -o 'thread backtrace all' -o 'quit'
     else
         auxv=$(gdb --quiet --core ${corefile} --batch -ex 'info auxv' 2>/dev/null)
+        echo "auxv $auxv"
         if [ $? -ne 0 ]; then
             echo "could not process ${corefile}"
             continue
-- 
2.17.1

From b929ea7acc33a2fda1ec10693736a2fa83d364e1 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH v3] WIP CI support for Cygwin.

ci-os-only: cygwin

See also: d8e78714-dc77-4a64-783f-e863ba4d951f@2ndquadrant.com

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed?  But if the larger image is slower to start, then maybe not...
---
 .cirrus.yml                               | 67 +++++++++++++++++++++++
 configure                                 |  2 +-
 configure.ac                              |  2 +-
 src/test/perl/PostgreSQL/Test/Cluster.pm  |  4 +-
 src/test/perl/PostgreSQL/Test/Utils.pm    | 12 +++-
 src/test/recovery/t/020_archive_status.pl |  2 +-
 src/tools/ci/cores_backtrace.sh           | 28 +++++++++-
 src/tools/ci/pg_ci_base.conf              |  2 +
 8 files changed, 109 insertions(+), 10 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index 4b7918ef456..84341ac1b94 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -34,6 +34,7 @@ on_failure: &on_failure
       - "**/*.log"
       - "**/*.diffs"
       - "**/regress_log_*"
+      - "**/*.stackdump"
     type: text/plain
 
 task:
@@ -464,6 +465,72 @@ task:
       type: text/plain
 
 
+task:
+  name: Windows - Cygwin
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  timeout_in: 90m
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: 4
+    TEST_JOBS: 1
+    CCACHE_DIR: /tmp/ccache
+    CONFIGURE_FLAGS: --enable-debug --enable-tap-tests --with-ldap --with-ssl=openssl --with-libxml --enable-cassert
+    # --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+    CCACHE_LOGFILE: ccache.log
+    EXTRA_REGRESS_OPTS: --max-connections=1
+    PG_TEST_EXTRA: ldap ssl # disable kerberos
+
+  windows_container:
+    image: cirrusci/windowsservercore:2019
+    os_version: 2019
+    cpu: $CPUS
+    memory: 4G
+
+  setup_additional_packages_script: |
+    choco install -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,perl-IPC-Run
+    REM libkrb5-devel,krb5-server
+    C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "net start cygserver"
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    C:\tools\cygwin\bin\bash.exe --login -c "id; uname -a; ulimit -a -H; ulimit -a -S; export"
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+
+  configure_script:
+    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done"
+
+  build_script:
+    #- C:\tools\cygwin\bin\bash.exe --login -c "ccache --max-size ${CCACHE_MAXSIZE}"
+    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --zero-stats"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && make -s -j ${BUILD_JOBS} world-bin"
+    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --show-stats"
+
+  upload_caches: ccache
+
+  test_world_script:
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/subscription"
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/recovery"
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s check ${CHECKFLAGS} -C src/bin -j 2"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 77m make -s -j ${TEST_JOBS} ${CHECK} PROVE_FLAGS='-j2 --timer' ${CHECKFLAGS}"
+
+  on_failure:
+    <<: *on_failure
+    cores_script:
+      - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
+
 task:
   name: CompilerWarnings
 
diff --git a/configure b/configure
index c5bc3823958..d147cf372db 100755
--- a/configure
+++ b/configure
@@ -17000,7 +17000,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index 61d0dd5d586..6dba8291d64 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1947,7 +1947,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index c8c7bc5045a..29894b6a98c 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -1052,7 +1052,7 @@ sub enable_restoring
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "$path\\\\%f" "%p"}
 	  : qq{cp "$path/%f" "%p"};
 
@@ -1122,7 +1122,7 @@ sub enable_archiving
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "%p" "$path\\\\%f"}
 	  : qq{cp "%p" "$path/%f"};
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 1ca2cc59170..c7786089a4b 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys' ||
+	  $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/test/recovery/t/020_archive_status.pl b/src/test/recovery/t/020_archive_status.pl
index e6e4eb56a90..0b2716fd7c9 100644
--- a/src/test/recovery/t/020_archive_status.pl
+++ b/src/test/recovery/t/020_archive_status.pl
@@ -26,7 +26,7 @@ my $primary_data = $primary->data_dir;
 # a portable solution, use an archive command based on a command known to
 # work but will fail: copy with an incorrect original path.
 my $incorrect_command =
-  $PostgreSQL::Test::Utils::windows_os
+  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
   ? qq{copy "%p_does_not_exist" "%f_does_not_exist"}
   : qq{cp "%p_does_not_exist" "%f_does_not_exist"};
 $primary->safe_psql(
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..64c980039cd 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,8 @@
 #! /bin/sh
 
+#set -e
+set -x
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -8,9 +11,21 @@ fi
 os=$1
 directory=$2
 
+findargs=''
 case $os in
     freebsd|linux|macos)
-    ;;
+        ;;
+    cygwin)
+        # XXX Evidently I don't know how to write two arguments here without pathname expansion later, other than eval.
+        #findargs='-name "*.stackdump"'
+        for corefile in $(find "$directory" -type f -name "*.stackdump") ; do
+            binary=`basename "$corefile" .stackdump`
+            echo;echo;
+            echo "dumping ${corefile} for ${binary}"
+            awk '/^0/{print $2}' $corefile |addr2line -f -i -e ./src/backend/postgres.exe
+        done
+        exit 0
+        ;;
     *)
         echo "unsupported operating system ${os}"
         exit 1
@@ -18,7 +33,7 @@ case $os in
 esac
 
 first=1
-for corefile in $(find "$directory" -type f) ; do
+for corefile in $(find "$directory" -type f $findargs) ; do
     if [ "$first" -eq 1 ]; then
         first=0
     else
@@ -28,6 +43,13 @@ for corefile in $(find "$directory" -type f) ; do
 
     if [ "$os" = 'macos' ]; then
         lldb -c $corefile --batch -o 'thread backtrace all' -o 'quit'
+    elif [ "$os" = 'cygwin' ]; then
+        # https://cirrus-ci.com/task/4964259674193920
+        #binary=${corefile%.stackdump}
+        #binary=${corefile#*/}
+        binary=`basename "$corefile" .stackdump`
+        echo "dumping ${corefile} for ${binary}"
+        awk '/^0/{print $2}' $corefile |addr2line -f -i -e ./src/backend/postgres.exe
     else
         auxv=$(gdb --quiet --core ${corefile} --batch -ex 'info auxv' 2>/dev/null)
         if [ $? -ne 0 ]; then
@@ -48,3 +70,5 @@ for corefile in $(find "$directory" -type f) ; do
         gdb --batch --quiet -ex "thread apply all bt full" -ex "quit" "$binary" "$corefile" 2>/dev/null
     fi
 done
+
+exit 0
diff --git a/src/tools/ci/pg_ci_base.conf b/src/tools/ci/pg_ci_base.conf
index d8faa9c26c1..206dd993ccc 100644
--- a/src/tools/ci/pg_ci_base.conf
+++ b/src/tools/ci/pg_ci_base.conf
@@ -12,3 +12,5 @@ log_connections = true
 log_disconnections = true
 log_line_prefix = '%m [%p][%b] %q[%a][%v:%x] '
 log_lock_waits = true
+
+data_sync_retry = on
-- 
2.17.1

From 0e0d5f33c8f5f3174b0576597971c80834bf76b8 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Fri, 30 Sep 2022 08:56:07 -0500
Subject: [PATCH 1/4] meson: PROVE is not required

It ought to be possible to build the application without running tests,
or without running TAP tests.  And it's essential for supporting
buildfarm/cygwin, where TAP tests consistently fail..
---
 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meson.build b/meson.build
index 2d225f706d2..fd8619d6997 100644
--- a/meson.build
+++ b/meson.build
@@ -323,7 +323,7 @@ python = find_program(get_option('PYTHON'), required: true, native: true)
 flex = find_program(get_option('FLEX'), native: true, version: '>= 2.5.35')
 bison = find_program(get_option('BISON'), native: true, version: '>= 2.3')
 sed = find_program(get_option('SED'), 'sed', native: true)
-prove = find_program(get_option('PROVE'), native: true)
+prove = find_program(get_option('PROVE'), native: true, required: false)
 tar = find_program(get_option('TAR'), native: true)
 gzip = find_program(get_option('GZIP'), native: true)
 program_lz4 = find_program(get_option('LZ4'), native: true, required: false)
-- 
2.25.1

From 330f91de111f8bee7969818c9001ee6bbc74a048 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Fri, 30 Sep 2022 13:39:43 -0500
Subject: [PATCH 2/4] meson: other fixes for cygwin

XXX: what about HAVE_BUGGY_STRTOF ?
---
 meson.build                  | 8 ++++++--
 src/port/meson.build         | 4 ++++
 src/test/regress/meson.build | 2 +-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/meson.build b/meson.build
index fd8619d6997..1c3e156f378 100644
--- a/meson.build
+++ b/meson.build
@@ -211,6 +211,10 @@ if host_system == 'aix'
 
 elif host_system == 'cygwin'
   cppflags += '-D_GNU_SOURCE'
+  dlsuffix = '.dll'
+  mod_link_args_fmt = ['@0@']
+  mod_link_with_name = 'lib@0@.exe.a'
+  mod_link_with_dir = 'libdir'
 
 elif host_system == 'darwin'
   dlsuffix = '.dylib'
@@ -2300,8 +2304,8 @@ gnugetopt_dep = cc.find_library('gnugetopt', required: false)
 #   (i.e., allow '-' as a flag character), so use our version on those platforms
 # - We want to use system's getopt_long() only if the system provides struct
 #   option
-always_replace_getopt = host_system in ['windows', 'openbsd', 'solaris']
-always_replace_getopt_long = host_system == 'windows' or not cdata.has('HAVE_STRUCT_OPTION')
+always_replace_getopt = host_system in ['windows', 'cygwin', 'openbsd', 'solaris']
+always_replace_getopt_long = host_system in ['windows', 'cygwin'] or not cdata.has('HAVE_STRUCT_OPTION')
 
 # Required on BSDs
 execinfo_dep = cc.find_library('execinfo', required: false)
diff --git a/src/port/meson.build b/src/port/meson.build
index c2222696f1b..0ba83cc7930 100644
--- a/src/port/meson.build
+++ b/src/port/meson.build
@@ -40,6 +40,10 @@ if host_system == 'windows'
     'win32setlocale.c',
     'win32stat.c',
   )
+elif host_system == 'cygwin'
+  pgport_sources += files(
+    'dirmod.c',
+  )
 endif
 
 if cc.get_id() == 'msvc'
diff --git a/src/test/regress/meson.build b/src/test/regress/meson.build
index 3dcfc11278f..6ec3c77af53 100644
--- a/src/test/regress/meson.build
+++ b/src/test/regress/meson.build
@@ -10,7 +10,7 @@ regress_sources = pg_regress_c + files(
 # patterns like ".*-.*-mingw.*". We probably can do better, but for now just
 # replace 'gcc' with 'mingw' on windows.
 host_tuple_cc = cc.get_id()
-if host_system == 'windows' and host_tuple_cc == 'gcc'
+if host_system in ['windows', 'cygwin'] and host_tuple_cc == 'gcc'
   host_tuple_cc = 'mingw'
 endif
 host_tuple = '@0@-@1@-@2@'.format(host_cpu, host_system, host_tuple_cc)
-- 
2.25.1

From a054c0bfb95213e0fd37a7f0c59ed29510f2b873 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH 3/4] WIP CI support for Cygwin.

ci-os-only: cygwin

See also: d8e78714-dc77-4a64-783f-e863ba4d951f@2ndquadrant.com

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed?  But if the larger image is slower to start, then maybe not...
---
 .cirrus.yml                               | 62 +++++++++++++++++++++++
 configure                                 |  2 +-
 configure.ac                              |  2 +-
 src/test/perl/PostgreSQL/Test/Cluster.pm  |  4 +-
 src/test/perl/PostgreSQL/Test/Utils.pm    | 12 +++--
 src/test/recovery/t/020_archive_status.pl |  2 +-
 src/tools/ci/cores_backtrace.sh           | 31 +++++++++++-
 src/tools/ci/pg_ci_base.conf              |  3 ++
 8 files changed, 108 insertions(+), 10 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index d95ff4bded8..cd4cbf9e5ed 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -477,6 +477,68 @@ task:
       type: text/plain
 
 
+task:
+  name: Windows - Cygwin
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  timeout_in: 90m
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: 4
+    TEST_JOBS: 1
+    CCACHE_DIR: /tmp/ccache
+    CONFIGURE_FLAGS: --enable-debug --enable-tap-tests --with-ldap --with-ssl=openssl --with-libxml --enable-cassert
+    # --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+    CCACHE_LOGFILE: ccache.log
+    EXTRA_REGRESS_OPTS: --max-connections=1
+    PG_TEST_EXTRA: ldap ssl # disable kerberos
+
+  windows_container:
+    image: cirrusci/windowsservercore:2019
+    os_version: 2019
+    cpu: $CPUS
+    memory: 4G
+
+  setup_additional_packages_script: |
+    choco install -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,perl-IPC-Run
+    REM libkrb5-devel,krb5-server
+    C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "net start cygserver"
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    C:\tools\cygwin\bin\bash.exe --login -c "id; uname -a; ulimit -a -H; ulimit -a -S; export"
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+
+  configure_script:
+    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done"
+
+  build_script:
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && make -s -j ${BUILD_JOBS} world-bin"
+    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --show-stats"
+
+  always:
+    upload_caches: ccache
+
+  test_world_script:
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 77m make -s -j ${TEST_JOBS} ${CHECK} PROVE_FLAGS='-j2 --timer' ${CHECKFLAGS}"
+
+  on_failure:
+    <<: *on_failure
+    cores_script:
+      - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
+
 task:
   name: CompilerWarnings
 
diff --git a/configure b/configure
index 5ea790d6380..f4b761db92d 100755
--- a/configure
+++ b/configure
@@ -16439,7 +16439,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index d80cdb5ca25..9b5f8c1cdb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1877,7 +1877,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index d80134b26f3..5b5e8e67137 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -1052,7 +1052,7 @@ sub enable_restoring
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "$path\\\\%f" "%p"}
 	  : qq{cp "$path/%f" "%p"};
 
@@ -1122,7 +1122,7 @@ sub enable_archiving
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "%p" "$path\\\\%f"}
 	  : qq{cp "%p" "$path/%f"};
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 99d33451064..fb7fca57239 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys' ||
+	  $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/test/recovery/t/020_archive_status.pl b/src/test/recovery/t/020_archive_status.pl
index 2108d50073a..fd46f45c627 100644
--- a/src/test/recovery/t/020_archive_status.pl
+++ b/src/test/recovery/t/020_archive_status.pl
@@ -26,7 +26,7 @@ my $primary_data = $primary->data_dir;
 # a portable solution, use an archive command based on a command known to
 # work but will fail: copy with an incorrect original path.
 my $incorrect_command =
-  $PostgreSQL::Test::Utils::windows_os
+  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
   ? qq{copy "%p_does_not_exist" "%f_does_not_exist"}
   : qq{cp "%p_does_not_exist" "%f_does_not_exist"};
 $primary->safe_psql(
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..27f93147e4e 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,8 @@
 #! /bin/sh
 
+#set -e
+set -x
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -8,9 +11,24 @@ fi
 os=$1
 directory=$2
 
+findargs=''
 case $os in
     freebsd|linux|macos)
-    ;;
+        ;;
+
+    cygwin)
+        # XXX Evidently I don't know how to write two arguments here without pathname expansion later, other than eval.
+        #findargs='-name "*.stackdump"'
+        for stack in $(find "$directory" -type f -name "*.stackdump") ; do
+            binary=`basename "$stack" .stackdump`
+            echo;echo;
+            echo "dumping ${stack} for ${binary}"
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./src/backend/$binary.exe"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e src/backend/postgres.exe
+        done
+        exit 0
+        ;;
+
     *)
         echo "unsupported operating system ${os}"
         exit 1
@@ -18,7 +36,7 @@ case $os in
 esac
 
 first=1
-for corefile in $(find "$directory" -type f) ; do
+for corefile in $(find "$directory" -type f $findargs) ; do
     if [ "$first" -eq 1 ]; then
         first=0
     else
@@ -28,6 +46,13 @@ for corefile in $(find "$directory" -type f) ; do
 
     if [ "$os" = 'macos' ]; then
         lldb -c $corefile --batch -o 'thread backtrace all' -o 'quit'
+    elif [ "$os" = 'cygwin' ]; then
+        # https://cirrus-ci.com/task/4964259674193920
+        #binary=${corefile%.stackdump}
+        #binary=${corefile#*/}
+        binary=`basename "$corefile" .stackdump`
+        echo "dumping ${corefile} for ${binary}"
+        awk '/^0/{print $2}' $corefile |addr2line -f -i -e ./src/backend/postgres.exe
     else
         auxv=$(gdb --quiet --core ${corefile} --batch -ex 'info auxv' 2>/dev/null)
         if [ $? -ne 0 ]; then
@@ -48,3 +73,5 @@ for corefile in $(find "$directory" -type f) ; do
         gdb --batch --quiet -ex "thread apply all bt full" -ex "quit" "$binary" "$corefile" 2>/dev/null
     fi
 done
+
+exit 0
diff --git a/src/tools/ci/pg_ci_base.conf b/src/tools/ci/pg_ci_base.conf
index d8faa9c26c1..0d43b387006 100644
--- a/src/tools/ci/pg_ci_base.conf
+++ b/src/tools/ci/pg_ci_base.conf
@@ -12,3 +12,6 @@ log_connections = true
 log_disconnections = true
 log_line_prefix = '%m [%p][%b] %q[%a][%v:%x] '
 log_lock_waits = true
+
+data_sync_retry = on
+shared_memory_type = mmap
-- 
2.25.1

From bd5fa65f2c9fbc3715382f2bb26d546ef3981729 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 28 Sep 2022 19:54:59 -0500
Subject: [PATCH 4/4] s!convert to meson

Note that PCH causes gcc to crash:
https://cirrus-ci.com/task/5856316085239808

https://cirrus-ci.com/task/5982327657463808
https://community.chocolatey.org/packages/Cygwin#versionhistory
a semi-relevant message about msys(not cygwin): https://www.postgresql.org/message-id/9f4f22be-f9f1-b350-bc06-521226b87f7a%40dunslane.net

ci-os-only: cygwin
---
 .cirrus.yml                     | 29 +++++++++++++++++------------
 src/tools/ci/cores_backtrace.sh |  4 ++--
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index cd4cbf9e5ed..006058a09b0 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -43,6 +43,7 @@ on_failure_meson: &on_failure_meson
       - "build*/testrun/**/*.log"
       - "build*/testrun/**/*.diffs"
       - "build*/testrun/**/regress_log_*"
+      - "**/*.stackdump"
     type: text/plain
 
   # In theory it'd be nice to upload the junit files meson generates, so that
@@ -480,30 +481,35 @@ task:
 task:
   name: Windows - Cygwin
   #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
   timeout_in: 90m
 
   env:
     CPUS: 4
-    BUILD_JOBS: 4
-    TEST_JOBS: 1
+    BUILD_JOBS: $CPUS
+    TEST_JOBS: $CPUS
     CCACHE_DIR: /tmp/ccache
-    CONFIGURE_FLAGS: --enable-debug --enable-tap-tests --with-ldap --with-ssl=openssl --with-libxml --enable-cassert
-    # --with-gssapi
-    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    CCACHE_DEPEND: 1
+    # compress because PCH are huge
+    CCACHE_COMPRESS: 1
+    # Actually, do not use ccache for PCH ... it crashes gcc
+    #CCACHE_SLOPPINESS: pch_defines,time_macros,include_file_ctime,include_file_mtime
     PG_TEST_USE_UNIX_SOCKETS: 1
     CCACHE_LOGFILE: ccache.log
     EXTRA_REGRESS_OPTS: --max-connections=1
     PG_TEST_EXTRA: ldap ssl # disable kerberos
+    CFLAGS: -Og -ggdb
 
   windows_container:
-    image: cirrusci/windowsservercore:2019
+    image: cirrusci/windowsservercore:2019-2022.06.23
     os_version: 2019
     cpu: $CPUS
     memory: 4G
 
   setup_additional_packages_script: |
     choco install -y --no-progress cygwin
-    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,perl-IPC-Run
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,meson,ninja
+    REM perl-IPC-Run,
     REM libkrb5-devel,krb5-server
     C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y"
     C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
@@ -521,21 +527,20 @@ task:
     folder: C:\tools\cygwin\tmp\ccache
 
   configure_script:
-    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && meson setup --buildtype=debug -Dcassert=true -Db_pch=false -Dssl=openssl -Duuid=e2fs -Dtap_tests=disabled -DPG_TEST_EXTRA='$PG_TEST_EXTRA' build"
 
   build_script:
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && make -s -j ${BUILD_JOBS} world-bin"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && ninja -C build -j${BUILD_JOBS}"
     - C:\tools\cygwin\bin\bash.exe --login -c "ccache --show-stats"
 
   always:
     upload_caches: ccache
 
   test_world_script:
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 77m make -s -j ${TEST_JOBS} ${CHECK} PROVE_FLAGS='-j2 --timer' ${CHECKFLAGS}"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && meson test $MTEST_ARGS --num-processes ${TEST_JOBS}"
 
   on_failure:
-    <<: *on_failure
+    <<: *on_failure_meson
     cores_script:
       - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
 
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 27f93147e4e..1e593429946 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -23,8 +23,8 @@ case $os in
             binary=`basename "$stack" .stackdump`
             echo;echo;
             echo "dumping ${stack} for ${binary}"
-            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./src/backend/$binary.exe"
-            awk '/^0/{print $2}' $stack |addr2line -f -i -e src/backend/postgres.exe
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./build/src/backend/$binary.exe"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./build/tmp_install/usr/local/pgsql/bin/postgres.exe
         done
         exit 0
         ;;
-- 
2.25.1

From 2741472080eceac5cb6d002c39eaf319d7f72b50 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Fri, 30 Sep 2022 13:39:43 -0500
Subject: [PATCH 1/3] meson: other fixes for cygwin

XXX: what about HAVE_BUGGY_STRTOF ?

See: 20221021034040.GT16921@telsasoft.com
---
 meson.build                  | 8 ++++++--
 src/port/meson.build         | 4 ++++
 src/test/regress/meson.build | 2 ++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build
index ce2f223a409..ed24370672a 100644
--- a/meson.build
+++ b/meson.build
@@ -211,6 +211,10 @@ if host_system == 'aix'
 
 elif host_system == 'cygwin'
   cppflags += '-D_GNU_SOURCE'
+  dlsuffix = '.dll'
+  mod_link_args_fmt = ['@0@']
+  mod_link_with_name = 'lib@0@.exe.a'
+  mod_link_with_dir = 'libdir'
 
 elif host_system == 'darwin'
   dlsuffix = '.dylib'
@@ -2301,8 +2305,8 @@ gnugetopt_dep = cc.find_library('gnugetopt', required: false)
 #   (i.e., allow '-' as a flag character), so use our version on those platforms
 # - We want to use system's getopt_long() only if the system provides struct
 #   option
-always_replace_getopt = host_system in ['windows', 'openbsd', 'solaris']
-always_replace_getopt_long = host_system == 'windows' or not cdata.has('HAVE_STRUCT_OPTION')
+always_replace_getopt = host_system in ['windows', 'cygwin', 'openbsd', 'solaris']
+always_replace_getopt_long = host_system in ['windows', 'cygwin'] or not cdata.has('HAVE_STRUCT_OPTION')
 
 # Required on BSDs
 execinfo_dep = cc.find_library('execinfo', required: false)
diff --git a/src/port/meson.build b/src/port/meson.build
index c2222696f1b..0ba83cc7930 100644
--- a/src/port/meson.build
+++ b/src/port/meson.build
@@ -40,6 +40,10 @@ if host_system == 'windows'
     'win32setlocale.c',
     'win32stat.c',
   )
+elif host_system == 'cygwin'
+  pgport_sources += files(
+    'dirmod.c',
+  )
 endif
 
 if cc.get_id() == 'msvc'
diff --git a/src/test/regress/meson.build b/src/test/regress/meson.build
index f1adcd9198c..72a23737fa7 100644
--- a/src/test/regress/meson.build
+++ b/src/test/regress/meson.build
@@ -12,6 +12,8 @@ regress_sources = pg_regress_c + files(
 host_tuple_cc = cc.get_id()
 if host_system == 'windows' and host_tuple_cc == 'gcc'
   host_tuple_cc = 'mingw'
+elif host_system == 'cygwin' and host_tuple_cc == 'gcc'
+  host_tuple_cc = 'cygwin'
 endif
 host_tuple = '@0@-@1@-@2@'.format(host_cpu, host_system, host_tuple_cc)
 
-- 
2.25.1

From 8f31be4d0bf036df890e32568dbc056c36fd57c5 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH 2/3] WIP CI support for Cygwin.

ci-os-only: cygwin

See also: d8e78714-dc77-4a64-783f-e863ba4d951f@2ndquadrant.com

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed?  But if the larger image is slower to start, then maybe not...
---
 .cirrus.yml                               | 76 +++++++++++++++++++++++
 configure                                 |  2 +-
 configure.ac                              |  2 +-
 src/test/perl/PostgreSQL/Test/Cluster.pm  |  4 +-
 src/test/perl/PostgreSQL/Test/Utils.pm    | 12 +++-
 src/test/recovery/t/020_archive_status.pl |  2 +-
 src/tools/ci/cores_backtrace.sh           | 33 +++++++++-
 src/tools/ci/pg_ci_base.conf              |  2 +
 8 files changed, 122 insertions(+), 11 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index 9f2282471a9..02b0f3b7045 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -464,6 +464,82 @@ task:
       type: text/plain
 
 
+task:
+  name: Windows - Cygwin
+  only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  timeout_in: 90m
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: 4
+    TEST_JOBS: 1
+    CCACHE_DIR: /tmp/ccache
+    CCACHE_LOGFILE: ccache.log
+    CONFIGURE_FLAGS: --enable-cassert --enable-debug --with-ldap --with-ssl=openssl --with-libxml
+    # --enable-tap-tests
+    # --disable-dynamicbase
+    # --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+    EXTRA_REGRESS_OPTS: --max-connections=1
+    PG_TEST_EXTRA: ldap ssl # disable kerberos
+
+  windows_container:
+    image: cirrusci/windowsservercore:2019-2022.06.23
+    os_version: 2019
+    cpu: $CPUS
+    memory: 4G
+
+  setup_additional_packages_script: |
+    choco install -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl
+    REM perl-IPC-Run,
+    REM libkrb5-devel,krb5-server
+    C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf"
+    C:\tools\cygwin\bin\bash.exe --login -c "net start cygserver"
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    C:\tools\cygwin\bin\bash.exe --login -c "id; uname -a; ulimit -a -H; ulimit -a -S; export"
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+    fingerprint_key: ccache/cygwin
+    reupload_on_changes: true
+
+  configure_script:
+    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done"
+
+  build_script:
+    #- C:\tools\cygwin\bin\bash.exe --login -c "ccache --max-size ${CCACHE_MAXSIZE}"
+    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --zero-stats"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && make -s -j ${BUILD_JOBS} world-bin"
+    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --show-stats"
+
+  upload_caches: ccache
+
+  test_world_script:
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/subscription"
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/recovery"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/modules/test_misc"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/interfaces/libpq"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/bin/psql"
+    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s check ${CHECKFLAGS} -C src/bin -j 2"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 77m make -s -j ${TEST_JOBS} ${CHECK} PROVE_FLAGS='-j2 --timer' ${CHECKFLAGS}"
+
+  on_failure:
+    <<: *on_failure_ac
+    cores_script:
+      - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
+
+
 task:
   name: CompilerWarnings
 
diff --git a/configure b/configure
index 3966368b8d9..68e366dcfc2 100755
--- a/configure
+++ b/configure
@@ -16494,7 +16494,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index f76b7ee31fc..33c5475520e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1878,7 +1878,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index d80134b26f3..5b5e8e67137 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -1052,7 +1052,7 @@ sub enable_restoring
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "$path\\\\%f" "%p"}
 	  : qq{cp "$path/%f" "%p"};
 
@@ -1122,7 +1122,7 @@ sub enable_archiving
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "%p" "$path\\\\%f"}
 	  : qq{cp "%p" "$path/%f"};
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 99d33451064..fb7fca57239 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys' ||
+	  $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/test/recovery/t/020_archive_status.pl b/src/test/recovery/t/020_archive_status.pl
index fe9ac06b32d..63452b49bd3 100644
--- a/src/test/recovery/t/020_archive_status.pl
+++ b/src/test/recovery/t/020_archive_status.pl
@@ -26,7 +26,7 @@ my $primary_data = $primary->data_dir;
 # a portable solution, use an archive command based on a command known to
 # work but will fail: copy with an incorrect original path.
 my $incorrect_command =
-  $PostgreSQL::Test::Utils::windows_os
+  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
   ? qq{copy "%p_does_not_exist" "%f_does_not_exist"}
   : qq{cp "%p_does_not_exist" "%f_does_not_exist"};
 $primary->safe_psql(
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..02bd50b10fa 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,8 @@
 #! /bin/sh
 
+#set -e
+set -x
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -8,17 +11,32 @@ fi
 os=$1
 directory=$2
 
+findargs=''
 case $os in
     freebsd|linux|macos)
-    ;;
+        ;;
+
+    cygwin)
+        # XXX Evidently I don't know how to write two arguments here without pathname expansion later, other than eval.
+        #findargs='-name "*.stackdump"'
+        for stack in $(find "$directory" -type f -name "*.stackdump") ; do
+            binary=`basename "$stack" .stackdump`
+            echo;echo;
+            echo "dumping ${stack} for ${binary}"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./src/backend/postgres.exe
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./src/backend/$binary.exe"
+        done
+        exit 0
+        ;;
+
     *)
         echo "unsupported operating system ${os}"
         exit 1
-    ;;
+        ;;
 esac
 
 first=1
-for corefile in $(find "$directory" -type f) ; do
+for corefile in $(find "$directory" -type f $findargs) ; do
     if [ "$first" -eq 1 ]; then
         first=0
     else
@@ -28,6 +46,13 @@ for corefile in $(find "$directory" -type f) ; do
 
     if [ "$os" = 'macos' ]; then
         lldb -c $corefile --batch -o 'thread backtrace all' -o 'quit'
+    elif [ "$os" = 'cygwin' ]; then
+        # https://cirrus-ci.com/task/4964259674193920
+        #binary=${corefile%.stackdump}
+        #binary=${corefile#*/}
+        binary=`basename "$corefile" .stackdump`
+        echo "dumping ${corefile} for ${binary}"
+        awk '/^0/{print $2}' $corefile |addr2line -f -i -e ./src/backend/postgres.exe
     else
         auxv=$(gdb --quiet --core ${corefile} --batch -ex 'info auxv' 2>/dev/null)
         if [ $? -ne 0 ]; then
@@ -48,3 +73,5 @@ for corefile in $(find "$directory" -type f) ; do
         gdb --batch --quiet -ex "thread apply all bt full" -ex "quit" "$binary" "$corefile" 2>/dev/null
     fi
 done
+
+exit 0
diff --git a/src/tools/ci/pg_ci_base.conf b/src/tools/ci/pg_ci_base.conf
index d8faa9c26c1..206dd993ccc 100644
--- a/src/tools/ci/pg_ci_base.conf
+++ b/src/tools/ci/pg_ci_base.conf
@@ -12,3 +12,5 @@ log_connections = true
 log_disconnections = true
 log_line_prefix = '%m [%p][%b] %q[%a][%v:%x] '
 log_lock_waits = true
+
+data_sync_retry = on
-- 
2.25.1

From 9aace45e27a1bc0bacd5922db9878d724b7bc492 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 28 Sep 2022 19:54:59 -0500
Subject: [PATCH 3/3] f!convert to meson

https://cirrus-ci.com/task/5982327657463808
https://community.chocolatey.org/packages/Cygwin#versionhistory

ci-os-only: cygwin
---
 .cirrus.yml                     | 34 +++++++++++++--------------------
 src/tools/ci/cores_backtrace.sh |  4 ++--
 2 files changed, 15 insertions(+), 23 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index 02b0f3b7045..57610e669e8 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -466,24 +466,24 @@ task:
 
 task:
   name: Windows - Cygwin
-  only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
   #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
-  timeout_in: 90m
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  #timeout_in: 90m
 
   env:
     CPUS: 4
-    BUILD_JOBS: 4
-    TEST_JOBS: 1
+    BUILD_JOBS: $CPUS
+    TEST_JOBS: $CPUS
     CCACHE_DIR: /tmp/ccache
     CCACHE_LOGFILE: ccache.log
-    CONFIGURE_FLAGS: --enable-cassert --enable-debug --with-ldap --with-ssl=openssl --with-libxml
-    # --enable-tap-tests
     # --disable-dynamicbase
     # --with-gssapi
     CONFIGURE_CACHE: /tmp/ccache/configure.cache
     PG_TEST_USE_UNIX_SOCKETS: 1
     EXTRA_REGRESS_OPTS: --max-connections=1
     PG_TEST_EXTRA: ldap ssl # disable kerberos
+    CC: ccache gcc
+    CFLAGS: -Og -ggdb
 
   windows_container:
     image: cirrusci/windowsservercore:2019-2022.06.23
@@ -493,7 +493,7 @@ task:
 
   setup_additional_packages_script: |
     choco install -y --no-progress cygwin
-    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,meson,ninja
     REM perl-IPC-Run,
     REM libkrb5-devel,krb5-server
     C:\tools\cygwin\bin\bash.exe --login -c "cygserver-config -y"
@@ -514,28 +514,20 @@ task:
     reupload_on_changes: true
 
   configure_script:
-    # Try to configure with the cache file, and retry without if it fails, in case the flags changed.
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && for i in 1 2; do ./configure --cache-file=${CONFIGURE_CACHE} ${CONFIGURE_FLAGS} CC='ccache gcc' CFLAGS='-Og -ggdb' && break; rm -v ${CONFIGURE_CACHE}; done"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && meson setup --buildtype=debug -Dcassert=true -Dssl=openssl -Duuid=e2fs -Dtap_tests=disabled -DPG_TEST_EXTRA='$PG_TEST_EXTRA' build"
 
   build_script:
-    #- C:\tools\cygwin\bin\bash.exe --login -c "ccache --max-size ${CCACHE_MAXSIZE}"
-    - C:\tools\cygwin\bin\bash.exe --login -c "ccache --zero-stats"
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && make -s -j ${BUILD_JOBS} world-bin"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && ninja -C build -j${BUILD_JOBS}"
     - C:\tools\cygwin\bin\bash.exe --login -c "ccache --show-stats"
 
-  upload_caches: ccache
+  always:
+    upload_caches: ccache
 
   test_world_script:
-    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/subscription"
-    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/recovery"
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/test/modules/test_misc"
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/interfaces/libpq"
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s -j ${TEST_JOBS} check ${CHECKFLAGS} -C src/bin/psql"
-    #- C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 44m make -s check ${CHECKFLAGS} -C src/bin -j 2"
-    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && timeout 77m make -s -j ${TEST_JOBS} ${CHECK} PROVE_FLAGS='-j2 --timer' ${CHECKFLAGS}"
+    - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && meson test $MTEST_ARGS --num-processes ${TEST_JOBS}"
 
   on_failure:
-    <<: *on_failure_ac
+    <<: *on_failure_meson
     cores_script:
       - C:\tools\cygwin\bin\bash.exe --login -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
 
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 02bd50b10fa..1f0f8795fc6 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -23,8 +23,8 @@ case $os in
             binary=`basename "$stack" .stackdump`
             echo;echo;
             echo "dumping ${stack} for ${binary}"
-            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./src/backend/postgres.exe
-            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./src/backend/$binary.exe"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./build/tmp_install/usr/local/pgsql/bin/postgres.exe
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./build/src/backend/$binary.exe"
         done
         exit 0
         ;;
-- 
2.25.1

From b07add11b8bf39f5bfbae4f9072470f31da97360 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH] WIP CI support for Cygwin.

ci-os-only: cygwin

See also: d8e78714-dc77-4a64-783f-e863ba4d951f@2ndquadrant.com

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed?  But if the larger image is slower to start, then maybe not...
---
 .cirrus.yml                                 | 83 +++++++++++++++++++++
 configure                                   |  2 +-
 configure.ac                                |  2 +-
 src/backend/replication/logical/snapbuild.c |  4 +-
 src/test/perl/PostgreSQL/Test/Cluster.pm    |  4 +-
 src/test/perl/PostgreSQL/Test/Utils.pm      | 12 ++-
 src/test/recovery/t/020_archive_status.pl   |  2 +-
 src/tools/ci/cores_backtrace.sh             | 19 ++++-
 8 files changed, 118 insertions(+), 10 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index d13726ed893..4507f734e94 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -737,6 +737,89 @@ task:
       type: text/plain
 
 
+task:
+  name: Windows - Cygwin
+
+  # due to resource constraints we don't run this task by default for now
+  trigger_type: manual
+  # worth using only_if despite being manual, otherwise this task will show up
+  # when e.g. ci-os-only: linux is used.
+  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  # otherwise it'll be sorted before other tasks
+  depends_on: SanityCheck
+
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  #timeout_in: 120m
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: $CPUS
+    TEST_JOBS: $CPUS
+    CCACHE_DIR: /tmp/ccache
+    CCACHE_LOGFILE: ccache.log
+    # --disable-dynamicbase
+    # --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+    EXTRA_REGRESS_OPTS: --max-connections=1
+    PG_TEST_EXTRA: ldap ssl # disable kerberos
+    CC: ccache gcc
+    CFLAGS: -Og -ggdb
+    BASH: C:\tools\cygwin\bin\bash.exe --login
+
+  #windows_container:
+    #image: cirrusci/windowsservercore:2019-2022.06.23
+    #os_version: 2019
+  compute_engine_instance:
+    image_project: $IMAGE_PROJECT
+    image: family/pg-ci-windows-ci-vs-2019
+    platform: windows
+    cpu: $CPUS
+    memory: 4G
+
+  setup_additional_packages_script: |
+    choco install -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,meson,ninja,perl-IPC-Run
+    REM libkrb5-devel,krb5-server
+    %BASH% -c "cygserver-config -y"
+    %BASH% -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
+    %BASH% -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf"
+    %BASH% -c "net start cygserver"
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    %BASH% -c "id; uname -a; ulimit -a -H; ulimit -a -S; export"
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+    fingerprint_key: ccache/cygwin
+    reupload_on_changes: true
+
+  configure_script: |
+    %BASH% -c "cd '%cd%' && meson setup --buildtype=debug -Dcassert=true -Dssl=openssl -Duuid=e2fs -DPG_TEST_EXTRA='$PG_TEST_EXTRA' build"
+
+  build_script: |
+    %BASH% -c "cd '%cd%' && ninja -C build -j${BUILD_JOBS}"
+    %BASH% -c "ccache --show-stats"
+
+  always:
+    upload_caches: ccache
+
+    #%BASH% -c "cd '%cd%' && echo 'data_sync_retry = on' >> src/tools/ci/pg_ci_base.conf"
+    #%BASH% -c "cd '%cd%' && echo 'wal_sync_method = fdatasync' >> src/tools/ci/pg_ci_base.conf"
+    # --repeat 9
+  test_world_script: |
+    %BASH% -c "cd '%cd%' && meson test $MTEST_ARGS --num-processes ${TEST_JOBS}"
+
+  on_failure:
+    <<: *on_failure_meson
+    cores_script: |
+      %BASH% -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
+
+
 task:
   name: CompilerWarnings
   # task that did not run, count as a success, so we need to recheck Linux'
diff --git a/configure b/configure
index 5d07fd0bb91..72d56f00534 100755
--- a/configure
+++ b/configure
@@ -16477,7 +16477,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index e9b74ced6ca..e0a9c332060 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1899,7 +1899,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 829c5681120..f0929600fcc 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1812,7 +1812,9 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
 	}
 
 	/* make sure we persist */
-	fsync_fname(path, false);
+	if (fsync_fname_ext(path, false, false, ERROR))
+		elog(ERROR, "failed to fsync");
+
 	fsync_fname("pg_logical/snapshots", true);
 
 	/*
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index 04921ca3a3d..31ac1d020a4 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -1097,7 +1097,7 @@ sub enable_restoring
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "$path\\\\%f" "%p"}
 	  : qq{cp "$path/%f" "%p"};
 
@@ -1167,7 +1167,7 @@ sub enable_archiving
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "%p" "$path\\\\%f"}
 	  : qq{cp "%p" "$path/%f"};
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 878e12b15ed..0c3f4dc35a0 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys'
+		|| $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/test/recovery/t/020_archive_status.pl b/src/test/recovery/t/020_archive_status.pl
index 13ada994dbb..0462d1d90c2 100644
--- a/src/test/recovery/t/020_archive_status.pl
+++ b/src/test/recovery/t/020_archive_status.pl
@@ -26,7 +26,7 @@ my $primary_data = $primary->data_dir;
 # a portable solution, use an archive command based on a command known to
 # work but will fail: copy with an incorrect original path.
 my $incorrect_command =
-  $PostgreSQL::Test::Utils::windows_os
+  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
   ? qq{copy "%p_does_not_exist" "%f_does_not_exist"}
   : qq{cp "%p_does_not_exist" "%f_does_not_exist"};
 $primary->safe_psql(
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..c49f9b07752 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,7 @@
 #! /bin/sh
 
+#set -e
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -8,9 +10,22 @@ fi
 os=$1
 directory=$2
 
+findargs=''
 case $os in
     freebsd|linux|macos)
-    ;;
+        ;;
+
+    cygwin)
+        for stack in $(find "$directory" -type f -name "*.stackdump") ; do
+            binary=`basename "$stack" .stackdump`
+            echo;echo;
+            echo "dumping ${stack} for ${binary}"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./build/tmp_install/usr/local/pgsql/bin/postgres.exe
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./build/src/backend/$binary.exe"
+        done
+        exit 0
+        ;;
+
     *)
         echo "unsupported operating system ${os}"
         exit 1
@@ -48,3 +63,5 @@ for corefile in $(find "$directory" -type f) ; do
         gdb --batch --quiet -ex "thread apply all bt full" -ex "quit" "$binary" "$corefile" 2>/dev/null
     fi
 done
+
+exit 0
-- 
2.25.1

From 16d2553e1e1d95aea1c215d7e909c7ea57fe160e Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 25 Jul 2022 23:05:10 +1200
Subject: [PATCH] WIP CI support for Cygwin.

See also: d8e78714-dc77-4a64-783f-e863ba4d951f@2ndquadrant.com

https://cirrus-ci.com/task/5145086722834432

XXX This should use a canned Docker image with all the right packages
installed?  But if the larger image is slower to start, then maybe not...

XXX trigger_type: manual
ci-os-only: cygwin
---
 .cirrus.yml                                 | 83 +++++++++++++++++++++
 configure                                   |  2 +-
 configure.ac                                |  2 +-
 src/backend/replication/logical/snapbuild.c |  4 +-
 src/test/perl/PostgreSQL/Test/Cluster.pm    |  4 +-
 src/test/perl/PostgreSQL/Test/Utils.pm      | 12 ++-
 src/test/recovery/t/020_archive_status.pl   |  2 +-
 src/tools/ci/cores_backtrace.sh             | 19 ++++-
 8 files changed, 118 insertions(+), 10 deletions(-)

diff --git a/.cirrus.yml b/.cirrus.yml
index d13726ed893..f704da2ff14 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -737,6 +737,89 @@ task:
       type: text/plain
 
 
+task:
+  name: Windows - Cygwin
+
+  # due to resource constraints we don't run this task by default for now
+  #XXX trigger_type: manual
+  # worth using only_if despite being manual, otherwise this task will show up
+  # when e.g. ci-os-only: linux is used.
+  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  # otherwise it'll be sorted before other tasks
+  depends_on: SanityCheck
+
+  #XXX only_if: $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*cygwin.*'
+  #timeout_in: 120m
+
+  env:
+    CPUS: 4
+    BUILD_JOBS: $CPUS
+    TEST_JOBS: $CPUS
+    CCACHE_DIR: /tmp/ccache
+    CCACHE_LOGFILE: ccache.log
+    # --disable-dynamicbase
+    # --with-gssapi
+    CONFIGURE_CACHE: /tmp/ccache/configure.cache
+    PG_TEST_USE_UNIX_SOCKETS: 1
+    EXTRA_REGRESS_OPTS: --max-connections=1
+    PG_TEST_EXTRA: ldap ssl # disable kerberos
+    CC: ccache gcc
+    CFLAGS: -Og -ggdb
+    BASH: C:\tools\cygwin\bin\bash.exe --login
+
+  #windows_container:
+    #image: cirrusci/windowsservercore:2019-2022.06.23
+    #os_version: 2019
+  compute_engine_instance:
+    image_project: $IMAGE_PROJECT
+    image: family/pg-ci-windows-ci-vs-2019
+    platform: windows
+    cpu: $CPUS
+    memory: 4G
+
+  setup_additional_packages_script: |
+    choco install -y --no-progress cygwin
+    C:\tools\cygwin\cygwinsetup.exe -q -P cygrunsrv,make,gcc-core,ccache,binutils,libtool,pkg-config,flex,bison,zlib-devel,libxml2-devel,libxslt-devel,libssl-devel,openldap-devel,libreadline-devel,perl,meson,ninja,perl-IPC-Run
+    REM libkrb5-devel,krb5-server
+    %BASH% -c "cygserver-config -y"
+    %BASH% -c "echo 'kern.ipc.semmni 1024' >> /etc/cygserver.conf"
+    %BASH% -c "echo 'kern.ipc.semmns 1024' >> /etc/cygserver.conf"
+    %BASH% -c "net start cygserver"
+
+  sysinfo_script: |
+    chcp
+    systeminfo
+    powershell -Command get-psdrive -psprovider filesystem
+    set
+    %BASH% -c "id; uname -a; ulimit -a -H; ulimit -a -S; export"
+
+  ccache_cache:
+    folder: C:\tools\cygwin\tmp\ccache
+    fingerprint_key: ccache/cygwin
+    reupload_on_changes: true
+
+  configure_script: |
+    %BASH% -c "cd '%cd%' && meson setup --buildtype=debug -Dcassert=true -Dssl=openssl -Duuid=e2fs -DPG_TEST_EXTRA='$PG_TEST_EXTRA' build"
+
+  build_script: |
+    %BASH% -c "cd '%cd%' && ninja -C build -j${BUILD_JOBS}"
+    %BASH% -c "ccache --show-stats"
+
+  always:
+    upload_caches: ccache
+
+    #%BASH% -c "cd '%cd%' && echo 'data_sync_retry = on' >> src/tools/ci/pg_ci_base.conf"
+    #%BASH% -c "cd '%cd%' && echo 'wal_sync_method = fdatasync' >> src/tools/ci/pg_ci_base.conf"
+    # --repeat 9
+  test_world_script: |
+    %BASH% -c "cd '%cd%' && meson test $MTEST_ARGS --num-processes ${TEST_JOBS}"
+
+  on_failure:
+    <<: *on_failure_meson
+    cores_script: |
+      %BASH% -c "cd '%cd%' && src/tools/ci/cores_backtrace.sh cygwin ."
+
+
 task:
   name: CompilerWarnings
   # task that did not run, count as a success, so we need to recheck Linux'
diff --git a/configure b/configure
index 5d07fd0bb91..72d56f00534 100755
--- a/configure
+++ b/configure
@@ -16477,7 +16477,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   case " $LIBOBJS " in
   *" getopt.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getopt.$ac_objext"
diff --git a/configure.ac b/configure.ac
index e9b74ced6ca..e0a9c332060 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1899,7 +1899,7 @@ fi
 
 # mingw has adopted a GNU-centric interpretation of optind/optreset,
 # so always use our version on Windows.
-if test "$PORTNAME" = "win32"; then
+if test "$PORTNAME" = "win32" -o "$PORTNAME" = "cygwin"; then
   AC_LIBOBJ(getopt)
   AC_LIBOBJ(getopt_long)
 fi
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 829c5681120..f0929600fcc 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1812,7 +1812,9 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
 	}
 
 	/* make sure we persist */
-	fsync_fname(path, false);
+	if (fsync_fname_ext(path, false, false, ERROR))
+		elog(ERROR, "failed to fsync");
+
 	fsync_fname("pg_logical/snapshots", true);
 
 	/*
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index 04921ca3a3d..31ac1d020a4 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -1097,7 +1097,7 @@ sub enable_restoring
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "$path\\\\%f" "%p"}
 	  : qq{cp "$path/%f" "%p"};
 
@@ -1167,7 +1167,7 @@ sub enable_archiving
 	# the path contains spaces.
 	$path =~ s{\\}{\\\\}g if ($PostgreSQL::Test::Utils::windows_os);
 	my $copy_command =
-	  $PostgreSQL::Test::Utils::windows_os
+	  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
 	  ? qq{copy "%p" "$path\\\\%f"}
 	  : qq{cp "%p" "$path/%f"};
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 878e12b15ed..0c3f4dc35a0 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -88,10 +88,11 @@ our @EXPORT = qw(
 
   $windows_os
   $is_msys2
+  $is_cygwin
   $use_unix_sockets
 );
 
-our ($windows_os, $is_msys2, $use_unix_sockets, $timeout_default,
+our ($windows_os, $is_msys2, $is_cygwin, $use_unix_sockets, $timeout_default,
 	$tmp_check, $log_path, $test_logfile);
 
 BEGIN
@@ -140,13 +141,18 @@ BEGIN
 	$ENV{PGAPPNAME} = basename($0);
 
 	# Must be set early
-	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys';
+	$windows_os = $Config{osname} eq 'MSWin32' || $Config{osname} eq 'msys'
+		|| $Config{osname} eq 'cygwin';
+
 	# Check if this environment is MSYS2.
 	$is_msys2 =
 	     $windows_os
 	  && -x '/usr/bin/uname'
 	  && `uname -or` =~ /^[2-9].*Msys/;
 
+	# Check if this environment is Cygwin
+	$is_cygwin = $Config{osname} eq 'cygwin';
+
 	if ($windows_os)
 	{
 		require Win32API::File;
@@ -707,7 +713,7 @@ sub dir_symlink
 {
 	my $oldname = shift;
 	my $newname = shift;
-	if ($windows_os)
+	if ($windows_os && !$is_cygwin)
 	{
 		$oldname =~ s,/,\\,g;
 		$newname =~ s,/,\\,g;
diff --git a/src/test/recovery/t/020_archive_status.pl b/src/test/recovery/t/020_archive_status.pl
index 13ada994dbb..0462d1d90c2 100644
--- a/src/test/recovery/t/020_archive_status.pl
+++ b/src/test/recovery/t/020_archive_status.pl
@@ -26,7 +26,7 @@ my $primary_data = $primary->data_dir;
 # a portable solution, use an archive command based on a command known to
 # work but will fail: copy with an incorrect original path.
 my $incorrect_command =
-  $PostgreSQL::Test::Utils::windows_os
+  $PostgreSQL::Test::Utils::windows_os && !$PostgreSQL::Test::Utils::is_cygwin
   ? qq{copy "%p_does_not_exist" "%f_does_not_exist"}
   : qq{cp "%p_does_not_exist" "%f_does_not_exist"};
 $primary->safe_psql(
diff --git a/src/tools/ci/cores_backtrace.sh b/src/tools/ci/cores_backtrace.sh
index 28d3cecfc67..c49f9b07752 100755
--- a/src/tools/ci/cores_backtrace.sh
+++ b/src/tools/ci/cores_backtrace.sh
@@ -1,5 +1,7 @@
 #! /bin/sh
 
+#set -e
+
 if [ $# -ne 2 ]; then
     echo "cores_backtrace.sh <os> <directory>"
     exit 1
@@ -8,9 +10,22 @@ fi
 os=$1
 directory=$2
 
+findargs=''
 case $os in
     freebsd|linux|macos)
-    ;;
+        ;;
+
+    cygwin)
+        for stack in $(find "$directory" -type f -name "*.stackdump") ; do
+            binary=`basename "$stack" .stackdump`
+            echo;echo;
+            echo "dumping ${stack} for ${binary}"
+            awk '/^0/{print $2}' $stack |addr2line -f -i -e ./build/tmp_install/usr/local/pgsql/bin/postgres.exe
+            #awk '/^0/{print $2}' $stack |addr2line -f -i -e "./build/src/backend/$binary.exe"
+        done
+        exit 0
+        ;;
+
     *)
         echo "unsupported operating system ${os}"
         exit 1
@@ -48,3 +63,5 @@ for corefile in $(find "$directory" -type f) ; do
         gdb --batch --quiet -ex "thread apply all bt full" -ex "quit" "$binary" "$corefile" 2>/dev/null
     fi
 done
+
+exit 0
-- 
2.25.1