Work around a subtle portability problem in use of printf %s format.

Depending on which spec you read, field widths and precisions in %s may be
counted either in bytes or characters.  Our code was assuming bytes, which
is wrong at least for glibc's implementation, and in any case libc might
have a different idea of the prevailing encoding than we do.  Hence, for
portable results we must avoid using anything more complex than just "%s"
unless the string to be printed is known to be all-ASCII.

This patch fixes the cases I could find, including the psql formatting
failure reported by Hernan Gonzalez.  In HEAD only, I also added comments
to some places where it appears safe to continue using "%.*s".

1 files changed, 3 insertions, 2 deletions

diff --git a/src/backend/lib/stringinfo.c b/src/backend/lib/stringinfo.c
index 88db51871e9..9ae2455000f 100644
--- a/src/backend/lib/stringinfo.c
+++ b/src/backend/lib/stringinfo.c
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	  $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.52 2010/01/02 16:57:45 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.53 2010/05/08 16:39:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -226,7 +226,8 @@ appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
 
 	/*
 	 * Keep a trailing null in place, even though it's probably useless for
-	 * binary data...
+	 * binary data.  (Some callers are dealing with text but call this
+	 * because their input isn't null-terminated.)
 	 */
 	str->data[str->len] = '\0';
 }