libpq: Remove deprecated connection parameters authtype and tty

The authtype parameter was deprecated and made inactive in commit
d5bbe2aca5, 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.

tty was deprecated in commit cb7fb3ca95 but most of the
infrastructure around it remained in place.

Author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/DDDF36F3-582A-4C02-8598-9B464CC42B34@yesql.se

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 no longer used and any value passed will
+        be ignored.
+      </para>
      </listitem>
     </varlistentry>
 
@@ -2119,10 +2124,10 @@ 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-       (This is obsolete, since the server no longer pays attention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 no longer does anything, but it 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);

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
@@ -192,14 +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 +233,6 @@ 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)},
@@ -1581,15 +1563,6 @@ 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)
@@ -4031,8 +4004,6 @@ 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)
@@ -6633,12 +6604,16 @@ PQport(const PGconn *conn)
 	return "";
 }
 
+/*
+ * No longer does anything, but the function remains for API backwards
+ * compatibility.
+ */
 char *
 PQtty(const PGconn *conn)
 {
 	if (!conn)
 		return NULL;
-	return conn->pgtty;
+	return "";
 }
 
 char *

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 */

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 */