From a54e3fa2c5b49601c25eb6ab82b00f79ab157f8a Mon Sep 17 00:00:00 2001
From: unknown <cmiller@zippy.cornsilk.net>
Date: Wed, 12 Mar 2008 17:03:50 -0400
Subject: [PATCH] Bug#34192: mysqldump from mysql 5.0.51 silently fails on
 dumping \ 	databases from 4.0 server

mysqldump treated a failure to set the results charset as a severe
error.

Now, don't try to set the charset for the SHOW CREATE TABLE statement,
if remote server's version is earlier than 4.1, which means it
doesn't support changing charsets.


client/mysqldump.c:
  Don't set the charset for receiving results if the server doesn't
  support it.
---
 client/mysqldump.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/client/mysqldump.c b/client/mysqldump.c
index 980013d539a..fdaf8a9727b 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -109,6 +109,8 @@ static char  *opt_password=0,*current_user=0,
              *log_error_file= NULL;
 static char **defaults_argv= 0;
 static char compatible_mode_normal_str[255];
+/* Server supports character_set_results session variable? */
+static my_bool server_supports_switching_charsets= TRUE;
 static ulong opt_compatible_mode= 0;
 #define MYSQL_OPT_MASTER_DATA_EFFECTIVE_SQL 1
 #define MYSQL_OPT_MASTER_DATA_COMMENTED_SQL 2
@@ -1011,11 +1013,27 @@ static int mysql_query_with_error_report(MYSQL *mysql_con, MYSQL_RES **res,
 }
 
 
+/**
+  Switch charset for results to some specified charset.  If the server does not
+  support character_set_results variable, nothing can be done here.  As for
+  whether something should be done here, future new callers of this function
+  should be aware that the server lacking the facility of switching charsets is
+  treated as success.
+
+  @note  If the server lacks support, then nothing is changed and no error
+         condition is returned.
+
+  @returns  whether there was an error or not
+*/
 static int switch_character_set_results(MYSQL *mysql, const char *cs_name)
 {
   char query_buffer[QUERY_LENGTH];
   size_t query_length;
 
+  /* Server lacks facility.  This is not an error, by arbitrary decision . */
+  if (!server_supports_switching_charsets)
+    return FALSE;
+
   query_length= my_snprintf(query_buffer,
                             sizeof (query_buffer),
                             "SET SESSION character_set_results = '%s'",
@@ -1111,11 +1129,14 @@ static int connect_to_db(char *host, char *user,char *passwd)
     DB_error(&mysql_connection, "when trying to connect");
     DBUG_RETURN(1);
   }
-  /*
-    Don't dump SET NAMES with a pre-4.1 server (bug#7997).
-  */
   if (mysql_get_server_version(&mysql_connection) < 40100)
+  {
+    /* Don't dump SET NAMES with a pre-4.1 server (bug#7997).  */
     opt_set_charset= 0;
+
+    /* Don't switch charsets for 4.1 and earlier.  (bug#34192). */
+    server_supports_switching_charsets= FALSE;
+  } 
   /*
     As we're going to set SQL_MODE, it would be lost on reconnect, so we
     cannot reconnect.