From 2463f5da3ccd67b266ee7a9b8c0906221a501b9e Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 10 Nov 2011 18:37:05 -0500
Subject: [PATCH] Throw nice error if server is too old to support psql's \ef
 or \sf command.

Previously, you'd get "function pg_catalog.pg_get_functiondef(integer) does
not exist", which is at best rather unprofessional-looking.  Back-patch
to 8.4 where \ef was introduced.

Josh Kupershmidt
---
 src/bin/psql/command.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 1339f336ff..786f4139b5 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -492,7 +492,13 @@ exec_command(const char *cmd,
 	 */
 	else if (strcmp(cmd, "ef") == 0)
 	{
-		if (!query_buf)
+		if (pset.sversion < 80400)
+		{
+			psql_error("The server (version %d.%d) does not support editing function source.\n",
+					   pset.sversion / 10000, (pset.sversion / 100) % 100);
+			status = PSQL_CMD_ERROR;
+		}
+		else if (!query_buf)
 		{
 			psql_error("no query buffer\n");
 			status = PSQL_CMD_ERROR;