From da9345151423180732d2928fe7fe6ff0b6a11d4d Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Fri, 20 Jan 2023 18:27:05 -0800
Subject: [PATCH v3 1/4] Fix error handling in libpqrcv_connect()

Author:
Reviewed-by:
Discussion: https://postgr.es/m/20230121011237.q52apbvlarfv6jm6@awork3.anarazel.de
Backpatch:
---
 .../libpqwalreceiver/libpqwalreceiver.c       | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index c40c6220db8..fefc8660259 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -175,10 +175,7 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname,
 	conn->streamConn = PQconnectStartParams(keys, vals,
 											 /* expand_dbname = */ true);
 	if (PQstatus(conn->streamConn) == CONNECTION_BAD)
-	{
-		*err = pchomp(PQerrorMessage(conn->streamConn));
-		return NULL;
-	}
+		goto bad_connection_errmsg;
 
 	/*
 	 * Poll connection until we have OK or FAILED status.
@@ -220,10 +217,7 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname,
 	} while (status != PGRES_POLLING_OK && status != PGRES_POLLING_FAILED);
 
 	if (PQstatus(conn->streamConn) != CONNECTION_OK)
-	{
-		*err = pchomp(PQerrorMessage(conn->streamConn));
-		return NULL;
-	}
+		goto bad_connection_errmsg;
 
 	if (logical)
 	{
@@ -234,9 +228,9 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname,
 		if (PQresultStatus(res) != PGRES_TUPLES_OK)
 		{
 			PQclear(res);
-			ereport(ERROR,
-					(errmsg("could not clear search path: %s",
-							pchomp(PQerrorMessage(conn->streamConn)))));
+			*err = psprintf(_("could not clear search path: %s"),
+							pchomp(PQerrorMessage(conn->streamConn)));
+			goto bad_connection;
 		}
 		PQclear(res);
 	}
@@ -244,6 +238,16 @@ libpqrcv_connect(const char *conninfo, bool logical, const char *appname,
 	conn->logical = logical;
 
 	return conn;
+
+	/* error path, using libpq's error message */
+bad_connection_errmsg:
+	*err = pchomp(PQerrorMessage(conn->streamConn));
+
+	/* error path, error already set */
+bad_connection:
+	PQfinish(conn->streamConn);
+	pfree(conn);
+	return NULL;
 }
 
 /*
-- 
2.38.0