A patch for Bug#11763166 (55847: SHOW WARNINGS returns empty

result set when SQLEXCEPTION is active.

The problem was in a hackish THD::no_warnings_for_error attribute.
When it was set, an error was not written to Warning_info -- only
Diagnostics_area state was changed. That means, Diagnostics_area
might contain error state, which is not present in Warning_info.

The user-visible problem was that in some cases SHOW WARNINGS
returned empty result set (i.e. there were no warnings) while
the previous SQL statement failed. According to the MySQL
protocol errors must be presented in warning list.

The main idea of this patch is to remove THD::no_warnings_for_error.
There were few places where it was used:
  - sql_admin.cc, handling of REPAIR TABLE USE_FRM.
  - sql_show.cc, when calling fill_schema_table_from_frm().
  - sql_show.cc, when calling fill_table().
The fix is to either use internal-error-handlers, or to use
temporary Warning_info storing warnings, which might be ignored.

This patch is needed to fix Bug 11763162 (55843).

1 files changed, 16 insertions, 12 deletions

diff --git a/sql/sql_error.h b/sql/sql_error.h
index 14dc5e6d12c..955b3767847 100644
--- a/sql/sql_error.h
+++ b/sql/sql_error.h
@@ -1,5 +1,4 @@
-/* Copyright (C) 2000-2003 MySQL AB,
-   Copyright (C) 2008-2009 Sun Microsystems, Inc
+/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -12,7 +11,7 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA */
 
 #ifndef SQL_ERROR_H
 #define SQL_ERROR_H
@@ -323,10 +322,13 @@ class Warning_info
 {
   /** A memory root to allocate warnings and errors */
   MEM_ROOT           m_warn_root;
+
   /** List of warnings of all severities (levels). */
   List <MYSQL_ERROR> m_warn_list;
+
   /** A break down of the number of warnings per severity (level). */
   uint	             m_warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
+
   /**
     The number of warnings of the current statement. Warning_info
     life cycle differs from statement life cycle -- it may span
@@ -334,20 +336,25 @@ class Warning_info
     m_statement_warn_count 0, whereas m_warn_list is not empty.
   */
   uint	             m_statement_warn_count;
+
   /*
     Row counter, to print in errors and warnings. Not increased in
     create_sort_index(); may differ from examined_row_count.
   */
   ulong              m_current_row_for_warning;
-  /** Used to optionally clear warnings only once per statement.  */
+
+  /** Used to optionally clear warnings only once per statement. */
   ulonglong          m_warn_id;
 
+  /** Indicates if push_warning() allows unlimited number of warnings. */
+  bool               m_allow_unlimited_warnings;
+
 private:
   Warning_info(const Warning_info &rhs); /* Not implemented */
   Warning_info& operator=(const Warning_info &rhs); /* Not implemented */
 public:
 
-  Warning_info(ulonglong warn_id_arg);
+  Warning_info(ulonglong warn_id_arg, bool allow_unlimited_warnings);
   ~Warning_info();
 
   /**
@@ -384,19 +391,13 @@ public:
   void append_warnings(THD *thd, List<MYSQL_ERROR> *src)
   {
     MYSQL_ERROR *err;
-    MYSQL_ERROR *copy;
     List_iterator_fast<MYSQL_ERROR> it(*src);
     /*
       Don't use ::push_warning() to avoid invocation of condition
       handlers or escalation of warnings to errors.
     */
     while ((err= it++))
-    {
-      copy= Warning_info::push_warning(thd, err->get_sql_errno(), err->get_sqlstate(),
-                                       err->get_level(), err->get_message_text());
-      if (copy)
-        copy->copy_opt_attributes(err);
-    }
+      Warning_info::push_warning(thd, err);
   }
 
   /**
@@ -462,6 +463,9 @@ public:
                             MYSQL_ERROR::enum_warning_level level,
                             const char* msg);
 
+  /** Add a new condition to the current list. */
+  MYSQL_ERROR *push_warning(THD *thd, const MYSQL_ERROR *sql_condition);
+
   /**
     Set the read only status for this statement area.
     This is a privileged operation, reserved for the implementation of