Backport of Bug#14171740 65562: STRING::SHRINK SHOULD BE A NO-OP WHEN ALLOCED=0

client/sql_string.h

 /*
-   Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2012, 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
@@ -195,8 +195,12 @@ public:
   }
   bool real_alloc(uint32 arg_length);			// Empties old string
   bool realloc(uint32 arg_length);
-  inline void shrink(uint32 arg_length)		// Shrink buffer
+
+  // Shrink the buffer, but only if it is allocated on the heap.
+  inline void shrink(uint32 arg_length)
   {
+    if (!is_alloced())
+      return;
     if (arg_length < Alloced_length)
     {
       char *new_ptr;
@@ -212,7 +216,7 @@ public:
       }
     }
   }
-  bool is_alloced() { return alloced; }
+  bool is_alloced() const { return alloced; }
   inline String& operator = (const String &s)
   {
     if (&s != this)

sql/sql_string.h

 /*
-   Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2012, 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
@@ -225,8 +225,12 @@ public:
   }
   bool real_alloc(uint32 arg_length);			// Empties old string
   bool realloc(uint32 arg_length);
-  inline void shrink(uint32 arg_length)		// Shrink buffer
+
+  // Shrink the buffer, but only if it is allocated on the heap.
+  inline void shrink(uint32 arg_length)
   {
+    if (!is_alloced())
+      return;
     if (arg_length < Alloced_length)
     {
       char *new_ptr;
@@ -242,7 +246,7 @@ public:
       }
     }
   }
-  bool is_alloced() { return alloced; }
+  bool is_alloced() const { return alloced; }
   inline String& operator = (const String &s)
   {
     if (&s != this)