Index: src/backend/utils/error/elog.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/error/elog.c,v
retrieving revision 1.208
diff -c -r1.208 elog.c
*** src/backend/utils/error/elog.c	17 Oct 2008 22:56:16 -0000	1.208
--- src/backend/utils/error/elog.c	27 Oct 2008 16:16:28 -0000
***************
*** 149,154 ****
--- 149,169 ----
  static void setup_formatted_log_time(void);
  static void setup_formatted_start_time(void);
  
+ 
+ /*
+  * in_error_recursion_trouble --- are we at risk of infinite error recursion?
+  *
+  * This function exists to provide common control of various fallback steps
+  * that we take if we think we are facing infinite error recursion.  See the
+  * callers for details.
+  */
+ bool
+ in_error_recursion_trouble(void)
+ {
+ 	/* Pull the plug if recurse more than once */
+ 	return (recursion_depth > 2);
+ }
+ 
  /*
   * errstart --- begin an error-reporting cycle
   *
***************
*** 261,272 ****
  		MemoryContextReset(ErrorContext);
  
  		/*
! 		 * If we recurse more than once, the problem might be something broken
  		 * in a context traceback routine.	Abandon them too.  We also abandon
  		 * attempting to print the error statement (which, if long, could
  		 * itself be the source of the recursive failure).
  		 */
! 		if (recursion_depth > 2)
  		{
  			error_context_stack = NULL;
  			debug_query_string = NULL;
--- 276,287 ----
  		MemoryContextReset(ErrorContext);
  
  		/*
! 		 * Infinite error recursion might be due to something broken
  		 * in a context traceback routine.	Abandon them too.  We also abandon
  		 * attempting to print the error statement (which, if long, could
  		 * itself be the source of the recursive failure).
  		 */
! 		if (in_error_recursion_trouble())
  		{
  			error_context_stack = NULL;
  			debug_query_string = NULL;
***************
*** 2408,2413 ****
--- 2423,2432 ----
  
  /*
   * error_severity --- get localized string representing elevel
+  *
+  * Note: in an error recursion situation, we stop localizing the tags
+  * for ERROR and above.  This is necessary because the problem might be
+  * failure to convert one of these strings to the client encoding.
   */
  static const char *
  error_severity(int elevel)
***************
*** 2437,2449 ****
  			prefix = _("WARNING");
  			break;
  		case ERROR:
! 			prefix = _("ERROR");
  			break;
  		case FATAL:
! 			prefix = _("FATAL");
  			break;
  		case PANIC:
! 			prefix = _("PANIC");
  			break;
  		default:
  			prefix = "???";
--- 2456,2477 ----
  			prefix = _("WARNING");
  			break;
  		case ERROR:
! 			if (in_error_recursion_trouble())
! 				prefix = "ERROR";
! 			else
! 				prefix = _("ERROR");
  			break;
  		case FATAL:
! 			if (in_error_recursion_trouble())
! 				prefix = "FATAL";
! 			else
! 				prefix = _("FATAL");
  			break;
  		case PANIC:
! 			if (in_error_recursion_trouble())
! 				prefix = "PANIC";
! 			else
! 				prefix = _("PANIC");
  			break;
  		default:
  			prefix = "???";
Index: src/backend/utils/mb/wchar.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/mb/wchar.c,v
retrieving revision 1.66
diff -c -r1.66 wchar.c
*** src/backend/utils/mb/wchar.c	15 Nov 2007 21:14:40 -0000	1.66
--- src/backend/utils/mb/wchar.c	27 Oct 2008 16:16:28 -0000
***************
*** 1567,1578 ****
  	for (j = 0; j < jlimit; j++)
  		p += sprintf(p, "%02x", (unsigned char) mbstr[j]);
  
! 	ereport(ERROR,
! 			(errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
! 	  errmsg("character 0x%s of encoding \"%s\" has no equivalent in \"%s\"",
! 			 buf,
! 			 pg_enc2name_tbl[src_encoding].name,
! 			 pg_enc2name_tbl[dest_encoding].name)));
  }
  
  #endif
--- 1567,1595 ----
  	for (j = 0; j < jlimit; j++)
  		p += sprintf(p, "%02x", (unsigned char) mbstr[j]);
  
! 	/*
! 	 * In an error recursion situation, don't try to translate the message.
! 	 * This gets us out of trouble if the problem is failure to convert
! 	 * the translated message to the client encoding.  Note that we have to
! 	 * spell the message slightly differently, which we do by sticking a
! 	 * space on the end --- using errmsg_internal() doesn't actually keep
! 	 * elog.c from calling gettext, it only prevents the string from being
! 	 * entered into the translation lists.
! 	 */
! 	if (in_error_recursion_trouble())
! 		ereport(ERROR,
! 				(errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
! 				 errmsg_internal("character 0x%s of encoding \"%s\" has no equivalent in \"%s\" ",
! 								 buf,
! 								 pg_enc2name_tbl[src_encoding].name,
! 								 pg_enc2name_tbl[dest_encoding].name)));
! 	else
! 		ereport(ERROR,
! 				(errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
! 				 errmsg("character 0x%s of encoding \"%s\" has no equivalent in \"%s\"",
! 						buf,
! 						pg_enc2name_tbl[src_encoding].name,
! 						pg_enc2name_tbl[dest_encoding].name)));
  }
  
  #endif
Index: src/include/utils/elog.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/utils/elog.h,v
retrieving revision 1.96
diff -c -r1.96 elog.h
*** src/include/utils/elog.h	9 Oct 2008 22:22:31 -0000	1.96
--- src/include/utils/elog.h	27 Oct 2008 16:16:28 -0000
***************
*** 324,329 ****
--- 324,330 ----
  /* Other exported functions */
  extern void DebugFileOpen(void);
  extern char *unpack_sql_state(int sql_state);
+ extern bool in_error_recursion_trouble(void);
  
  #ifdef HAVE_SYSLOG
  extern void set_syslog_parameters(const char *ident, int facility);