authtype parameter in libpq

From c0fccb72d9889179083c2abcffa10810f8e2a437 Mon Sep 17 00:00:00 2001
From: Daniel Gustafsson <daniel@yesql.se>
Date: Thu, 4 Mar 2021 15:47:31 +0100
Subject: [PATCH v2] Remove deprecated parameters authtype and pqtty

The authtype parameter was deprecated and made inactive in commit
d5bbe2aca55bc8, but the environment variable was left defined and
thus tested with a getenv call even though the value is of no use.
Also, if it would exist it would be copied but never freed as the
cleanup code had been removed.

pgtty was deprecated in commit cb7fb3ca958ec8bd5a14e7 but most of
the infrastructure around it remained in place.

This removes both parameters completely, making PQtty always return
an empty string for non-NULL conn objects to maintain API stability.

Discussion: https://postgr.es/m/DDDF36F3-582A-4C02-8598-9B464CC42B34@yesql.se
---
 doc/src/sgml/libpq.sgml           | 14 +++++++++----
 src/interfaces/libpq/fe-connect.c | 34 +++++--------------------------
 src/interfaces/libpq/libpq-fe.h   |  4 ++--
 src/interfaces/libpq/libpq-int.h  |  2 --
 src/test/examples/testlibpq4.c    |  8 +++-----
 5 files changed, 20 insertions(+), 42 deletions(-)

diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 0553279314..8fb42f1f38 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -232,6 +232,11 @@ PGconn *PQsetdbLogin(const char *pghost,
         if it had been passed to <xref linkend="libpq-PQconnectdb"/>, and the remaining
         parameters are then applied as specified for <xref linkend="libpq-PQconnectdbParams"/>.
       </para>
+
+      <para>
+        <literal>pgtty</literal> is deprecated and any value passed will be
+        discarded, it remains for backwards compatibility.
+      </para>
      </listitem>
     </varlistentry>
 
@@ -2136,10 +2141,11 @@ char *PQport(const PGconn *conn);
 
      <listitem>
       <para>
-       Returns the debug <acronym>TTY</acronym> of the connection.
-       (This is obsolete, since the server no longer pays attention
-       to the <acronym>TTY</acronym> setting, but the function remains
-       for backward compatibility.)
+       This function is deprecated since the server no longer pays
+       attention to the <acronym>TTY</acronym> setting, but the function
+       remains for backwards compatibility. The function always return an
+       empty string, or <symbol>NULL</symbol> if the
+       <parameter>conn</parameter> argument is <symbol>NULL</symbol>. 
 
 <synopsis>
 char *PQtty(const PGconn *conn);
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index f83af03d0a..4154105426 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -120,9 +120,7 @@ static int	ldapServiceLookup(const char *purl, PQconninfoOption *options,
  * by environment variables
  */
 #define DefaultHost		"localhost"
-#define DefaultTty		""
 #define DefaultOption	""
-#define DefaultAuthtype		  ""
 #ifdef USE_SSL
 #define DefaultChannelBinding	"prefer"
 #else
@@ -192,13 +190,6 @@ typedef struct _internalPQconninfoOption
 } internalPQconninfoOption;
 
 static const internalPQconninfoOption PQconninfoOptions[] = {
-	/*
-	 * "authtype" is no longer used, so mark it "don't show".  We keep it in
-	 * the array so as not to reject conninfo strings from old apps that might
-	 * still try to set it.
-	 */
-	{"authtype", "PGAUTHTYPE", DefaultAuthtype, NULL,
-	"Database-Authtype", "D", 20, -1},
 
 	{"service", "PGSERVICE", NULL, NULL,
 	"Database-Service", "", 20, -1},
@@ -243,14 +234,6 @@ static const internalPQconninfoOption PQconninfoOptions[] = {
 		"Client-Encoding", "", 10,
 	offsetof(struct pg_conn, client_encoding_initial)},
 
-	/*
-	 * "tty" is no longer used either, but keep it present for backwards
-	 * compatibility.
-	 */
-	{"tty", "PGTTY", DefaultTty, NULL,
-		"Backend-Debug-TTY", "D", 40,
-	offsetof(struct pg_conn, pgtty)},
-
 	{"options", "PGOPTIONS", DefaultOption, NULL,
 		"Backend-Options", "", 40,
 	offsetof(struct pg_conn, pgoptions)},
@@ -1578,15 +1561,6 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
 			goto oom_error;
 	}
 
-	if (pgtty && pgtty[0] != '\0')
-	{
-		if (conn->pgtty)
-			free(conn->pgtty);
-		conn->pgtty = strdup(pgtty);
-		if (!conn->pgtty)
-			goto oom_error;
-	}
-
 	if (login && login[0] != '\0')
 	{
 		if (conn->pguser)
@@ -4028,8 +4002,6 @@ freePGconn(PGconn *conn)
 		free(conn->pghostaddr);
 	if (conn->pgport)
 		free(conn->pgport);
-	if (conn->pgtty)
-		free(conn->pgtty);
 	if (conn->connect_timeout)
 		free(conn->connect_timeout);
 	if (conn->pgtcp_user_timeout)
@@ -6632,12 +6604,16 @@ PQport(const PGconn *conn)
 	return "";
 }
 
+/*
+ * The pqtty parameter has been removed, but the function remains for API
+ * backwards compatibility.
+ */
 char *
 PQtty(const PGconn *conn)
 {
 	if (!conn)
 		return NULL;
-	return conn->pgtty;
+	return "";
 }
 
 char *
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index fa9b62a844..fde2e60888 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -268,8 +268,8 @@ extern PGconn *PQsetdbLogin(const char *pghost, const char *pgport,
 							const char *dbName,
 							const char *login, const char *pwd);
 
-#define PQsetdb(M_PGHOST,M_PGPORT,M_PGOPT,M_PGTTY,M_DBNAME)  \
-	PQsetdbLogin(M_PGHOST, M_PGPORT, M_PGOPT, M_PGTTY, M_DBNAME, NULL, NULL)
+#define PQsetdb(M_PGHOST,M_PGPORT,M_PGOPT,M_UNUSED,M_DBNAME)  \
+	PQsetdbLogin(M_PGHOST, M_PGPORT, M_PGOPT, NULL, M_DBNAME, NULL, NULL)
 
 /* close the current connection and free the PGconn data structure */
 extern void PQfinish(PGconn *conn);
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 8d51e6ed9f..adf149a76f 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -338,8 +338,6 @@ struct pg_conn
 								 * precedence over pghost. */
 	char	   *pgport;			/* the server's communication port number, or
 								 * a comma-separated list of ports */
-	char	   *pgtty;			/* tty on which the backend messages is
-								 * displayed (OBSOLETE, NOT USED) */
 	char	   *connect_timeout;	/* connection timeout (numeric string) */
 	char	   *pgtcp_user_timeout; /* tcp user timeout (numeric string) */
 	char	   *client_encoding_initial;	/* encoding to use */
diff --git a/src/test/examples/testlibpq4.c b/src/test/examples/testlibpq4.c
index dd11bbc46d..da4443072d 100644
--- a/src/test/examples/testlibpq4.c
+++ b/src/test/examples/testlibpq4.c
@@ -50,8 +50,7 @@ main(int argc, char **argv)
 {
 	char	   *pghost,
 			   *pgport,
-			   *pgoptions,
-			   *pgtty;
+			   *pgoptions;
 	char	   *dbName1,
 			   *dbName2;
 	char	   *tblName;
@@ -88,13 +87,12 @@ main(int argc, char **argv)
 	pgport = NULL;				/* port of the backend */
 	pgoptions = NULL;			/* special options to start up the backend
 								 * server */
-	pgtty = NULL;				/* debugging tty for the backend */
 
 	/* make a connection to the database */
-	conn1 = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName1);
+	conn1 = PQsetdb(pghost, pgport, pgoptions, NULL, dbName1);
 	check_prepare_conn(conn1, dbName1);
 
-	conn2 = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName2);
+	conn2 = PQsetdb(pghost, pgport, pgoptions, NULL, dbName2);
 	check_prepare_conn(conn2, dbName2);
 
 	/* start a transaction block */
-- 
2.21.1 (Apple Git-122.3)