From 9a413b791364152d44838d329f0efe3cc7db4d22 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Fri, 3 Mar 2023 13:39:26 +0900
Subject: [PATCH v1] Widen unquoted value acceptance in configuration file

Numeric configuration parameters can accept real numbers like '10.3',
but the values cannot be followed by a unit if they are not quoted. In
addition, certain formats like '1e4' are not accepted unless they are
not quoted. This commit changes the configuration file parser to
accept all of these values without the need for quotes.
---
 src/backend/utils/misc/guc-file.l             |  2 +-
 src/test/modules/test_misc/t/003_check_guc.pl | 41 +++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index 41d62a9f23..ca4add9710 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -76,7 +76,7 @@ UNIT_LETTER		[a-zA-Z]
 INTEGER			{SIGN}?({DIGIT}+|0x{HEXDIGIT}+){UNIT_LETTER}*
 
 EXPONENT		[Ee]{SIGN}?{DIGIT}+
-REAL			{SIGN}?{DIGIT}*"."{DIGIT}*{EXPONENT}?
+REAL			{SIGN}?(("."{DIGIT}+|{DIGIT}+"."{DIGIT}*){EXPONENT}?|{DIGIT}+{EXPONENT}){UNIT_LETTER}*
 
 LETTER			[A-Za-z_\200-\377]
 LETTER_OR_DIGIT [A-Za-z_0-9\200-\377]
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index e9f33f3c77..053fbe336d 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -106,4 +106,45 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# check if GUC parser accepts some unquoted values accepted by strtod()
+my $conffile = $node->data_dir . "/postgresql.conf";
+my $conf = slurp_file($conffile);
+## without units
+my $lines =
+  join("\n", map {"checkpoint_completion_target = $_"}
+	   ('0.1', '1.', '.1', '1e-1', '.1e0', '1.e-01'));
+## with units
+$lines .= "\n" .
+  join("\n", map {"work_mem = ${_}MB"}
+	   ('0.3', '1.', '.3', '+3e-1', '-.3e0', '1.e01'));
+$node->append_conf('postgresql.conf', $lines);
+
+$node->reload();
+## has the last value been read?
+ok ($node->poll_query_until('postgres',
+			"SELECT setting::int = 10240 FROM pg_settings WHERE name = 'work_mem'"),
+	'all variations of real number parameter values passed');
+
+# check if parser correctly rejects some invalid patterns
+my $n = 0;
+foreach my $val ('.', '.e3')
+{
+	$n++ if (test_one_value($node, $val, $conf));
+}
+ok($n == 2, "parser succesfully rejected invalid values");
+
 done_testing();
+
+sub test_one_value
+{
+  my ($node, $value, $base_conf) = @_;
+
+  open(my $fh, '>', $conffile) || die "failed to open $conffile";
+  print $fh $conf . "\nwork_mem=$value\n";
+  close($fh);
+
+  my $logstart = -s $node->logfile;
+  $node->reload();
+  return $node->wait_for_log('syntax error in file ".*postgresql.conf"',
+							 $logstart);
+}
-- 
2.31.1