From: Jorgen Loland
Date: January 13 2011 1:59pm
Subject: Re: bzr commit into mysql-trunk branch (tor.didriksen:3498) Bug#59241
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Tor,

Thank you for fixing this by adding proper assignment and copy operators. The 
patch is approved, but I want you to add a unit test that would fail prior to 
the fix, e.g. like this:

TEST_F(DecimalTest, CopyAndCompare)
{
   ulonglong val= 42;
   EXPECT_EQ(0, ulonglong2decimal(val, &d1));

   d2= d1;                                       // operator=()
   my_decimal d3(d1);                            // Copy constructor.

   EXPECT_EQ(0, my_decimal_cmp(&d1, &d2));
   EXPECT_EQ(0, my_decimal_cmp(&d2, &d3));
   EXPECT_EQ(0, my_decimal_cmp(&d3, &d1));

   ulonglong val1, val2, val3;
   EXPECT_EQ(0, decimal2ulonglong(&d1, &val1));
   EXPECT_EQ(0, decimal2ulonglong(&d2, &val2));
   EXPECT_EQ(0, decimal2ulonglong(&d3, &val3));
   EXPECT_EQ(val, val1);
   EXPECT_EQ(val, val2);
   EXPECT_EQ(val, val3);

+  val= 45;
+  EXPECT_EQ(0, ulonglong2decimal(val, &d1));
+  EXPECT_EQ(1, my_decimal_cmp(&d1, &d2));
}



On 01/13/2011 12:37 PM, Tor Didriksen wrote:
> #At file:///export/home/didrik/repo/trunk-bug59241divmod/ based on revid:ole.john.aske@stripped
>
>   3498 Tor Didriksen	2011-01-13
>        Bug #59241 invalid memory read in do_div_mod with doubly assigned variables
>
>        Fix: copy my_decimal by value, to avoid dangling pointers.
>       @ mysql-test/r/func_math.result
>          New test case.
>       @ mysql-test/t/func_math.test
>          New test case.
>       @ sql/item_cmpfunc.cc
>          No need to call fix_buffer_pointer() anymore.
>       @ sql/item_func.cc
>          Copy my_decimal by value, to avoid dangling pointers.
>       @ sql/my_decimal.h
>          Implement proper copy constructor and assignment operator for my_decimal.
>       @ sql/sql_analyse.cc
>          No need to call fix_buffer_pointer() anymore.
>       @ strings/decimal.c
>          Remove #line directive: it messes up TAGS and it confuses gdb when debugging.
>       @ unittest/gunit/CMakeLists.txt
>          New unit test.
>       @ unittest/gunit/my_decimal-t.cc
>          Unit test for my_decimal copy constructor and assignment operator.
>
>      added:
>        unittest/gunit/my_decimal-t.cc
>      modified:
>        mysql-test/r/func_math.result
>        mysql-test/t/func_math.test
>        sql/item_cmpfunc.cc
>        sql/item_func.cc
>        sql/my_decimal.h
>        sql/sql_analyse.cc
>        strings/decimal.c
>        unittest/gunit/CMakeLists.txt


-- 
Jørgen Løland | Senior Software Engineer | +47 73842138
Oracle MySQL
Trondheim, Norway