Fixed BUG #12440: "Incorrect processing of time values containing

 long fraction and/or large exponent part".

mysql-test/r/type_time.result

@@ -85,3 +85,27 @@ sec_to_time(time_to_sec(t))
 13:00:00
 09:00:00
 drop table t1;
+SELECT CAST(235959.123456 AS TIME);
+CAST(235959.123456 AS TIME)
+23:59:59.123456
+SELECT CAST(0.235959123456e+6 AS TIME);
+CAST(0.235959123456e+6 AS TIME)
+23:59:59.123456
+SELECT CAST(235959123456e-6 AS TIME);
+CAST(235959123456e-6 AS TIME)
+23:59:59.123456
+SELECT CAST(235959.1234567 AS TIME);
+CAST(235959.1234567 AS TIME)
+23:59:59.123456
+Warnings:
+Warning	1292	Truncated incorrect time value: '235959.1234567'
+SELECT CAST(0.2359591234567e6 AS TIME);
+CAST(0.2359591234567e6 AS TIME)
+23:59:59.123456
+Warnings:
+Warning	1292	Truncated incorrect time value: '235959.1234567'
+SELECT CAST(0.2359591234567e+30 AS TIME);
+CAST(0.2359591234567e+30 AS TIME)
+NULL
+Warnings:
+Warning	1292	Truncated incorrect time value: '2.359591234567e+29'

mysql-test/t/type_time.test

@@ -21,4 +21,18 @@ select t, time_to_sec(t),sec_to_time(time_to_sec(t)) from t1;
 select sec_to_time(time_to_sec(t)) from t1;
 drop table t1;
 
+#
+# BUG #12440: Incorrect processing of time values containing
+# long fraction part and/or large exponent part.
+#
+# These must return normal result:
+SELECT CAST(235959.123456 AS TIME);
+SELECT CAST(0.235959123456e+6 AS TIME);
+SELECT CAST(235959123456e-6 AS TIME);
+# These must cut fraction part and produce warning:
+SELECT CAST(235959.1234567 AS TIME);
+SELECT CAST(0.2359591234567e6 AS TIME);
+# This must return NULL and produce warning:
+SELECT CAST(0.2359591234567e+30 AS TIME);
+
 # End of 4.1 tests

sql-common/my_time.c

@@ -514,18 +514,34 @@ fractional:
   /* Get fractional second part */
   if ((end-str) >= 2 && *str == '.' && my_isdigit(&my_charset_latin1,str[1]))
   {
-    uint field_length=5;
+    int field_length= 5;
     str++; value=(uint) (uchar) (*str - '0');
-    while (++str != end && 
-           my_isdigit(&my_charset_latin1,str[0]) && 
-           field_length--)
-      value=value*10 + (uint) (uchar) (*str - '0');
-    if (field_length)
+    while (++str != end && my_isdigit(&my_charset_latin1, *str))
+    {
+      if (field_length-- > 0)
+        value= value*10 + (uint) (uchar) (*str - '0');
+    }
+    if (field_length > 0)
       value*= (long) log_10_int[field_length];
+    else if (field_length < 0)
+      *was_cut= 1;
     date[4]=value;
   }
   else
     date[4]=0;
+    
+  /* Check for exponent part: E<gigit> | E<sign><digit> */
+  /* (may occur as result of %g formatting of time value) */
+  if ((end - str) > 1 &&
+      (*str == 'e' || *str == 'E') &&
+      (my_isdigit(&my_charset_latin1, str[1]) ||
+       ((str[1] == '-' || str[1] == '+') &&
+        (end - str) > 2 &&
+        my_isdigit(&my_charset_latin1, str[2]))))
+  {
+    *was_cut= 1;
+    return 1;
+  }
 
   if (internal_format_positions[7] != 255)
   {