Fix for CONC-371: Incorrect fractional part conversion

If a datetime or time value is represented a a string and has a fractional part with less than 6 digits,
it should be interpreted as a 6-digit representation:

.9 becomes 900000
.09 becomes 90000
etc.

libmariadb/ma_stmt_codec.c

@@ -198,7 +198,9 @@ double my_atod(const char *number, const char *end, int *error)
 
 my_bool str_to_TIME(const char *str, size_t length, MYSQL_TIME *tm)
 {
-  char *start= alloca(length + 1);
+  char *start= alloca(length + 1),
+       *begin= start,
+       *frac;
   my_bool is_date= 0, is_time= 0;
 
   memset(tm, 0, sizeof(MYSQL_TIME));
@@ -250,11 +252,15 @@ my_bool str_to_TIME(const char *str, size_t length, MYSQL_TIME *tm)
   else
     tm->time_type= MYSQL_TIMESTAMP_TIME;
 
-  if (strchr(start, '.')) /* fractional seconds */
+  if ((frac= strchr(start, '.'))) /* fractional seconds */
   {
+    size_t frac_len= (begin + length) - (frac + 1);
     if (sscanf(start, "%d:%d:%d.%ld", &tm->hour, &tm->minute,
                                  &tm->second,&tm->second_part) < 4)
       goto error;
+    /* conc-371 */
+    if (frac_len < 6)
+      tm->second_part*= pow(10, 6 - frac_len);
   } else {
     if (sscanf(start, "%d:%d:%d", &tm->hour, &tm->minute,
                                  &tm->second) < 3)

unittest/libmariadb/ps_bugs.c

@@ -4783,6 +4783,54 @@ static int test_conc344(MYSQL *mysql)
   return OK;
 }
 
+
+static int test_conc_fraction(MYSQL *mysql)
+{
+  MYSQL_TIME tm;
+  MYSQL_BIND bind[1];
+  char query[1024];
+  int i;
+  MYSQL_STMT *stmt= mysql_stmt_init(mysql);
+  int rc;
+
+  for (i=0; i < 6; i++)
+  {
+    unsigned long expected= 0;
+    sprintf(query, "SELECT '2018-11-05 22:25:59.%0*d'", i + 1, 9);
+
+    diag("%d: %s", i, query);
+
+    rc= mysql_stmt_prepare(stmt, SL(query));
+    check_stmt_rc(rc, stmt);
+
+    rc= mysql_stmt_execute(stmt);
+    check_stmt_rc(rc, stmt);
+
+    check_stmt_rc(rc, stmt);
+    rc= mysql_stmt_store_result(stmt);
+
+    memset(bind, 0, sizeof(MYSQL_BIND));
+    bind[0].buffer_type= MYSQL_TYPE_DATETIME;
+    bind[0].buffer= &tm;
+    bind[0].buffer_length= sizeof(MYSQL_TIME);
+
+    rc= mysql_stmt_bind_result(stmt, bind);
+    check_stmt_rc(rc, stmt);
+    rc= mysql_stmt_fetch(stmt);
+    check_stmt_rc(rc, stmt);
+
+    diag("second_part: %ld", tm.second_part);
+
+    expected= 9 * powl(10, (5 - i));
+
+    FAIL_IF(tm.second_part != expected, "expected fractional part to be 900000");
+
+  }
+  mysql_stmt_close(stmt);
+  return OK;
+}
+
+
 struct my_tests_st my_tests[] = {
   {"test_conc344", test_conc344, TEST_CONNECTION_NEW, 0, NULL, NULL},
   {"test_conc334", test_conc334, TEST_CONNECTION_NEW, 0, NULL, NULL},
@@ -4857,6 +4905,7 @@ struct my_tests_st my_tests[] = {
   {"test_sshort_bug", test_sshort_bug, TEST_CONNECTION_DEFAULT, 0, NULL , NULL},
   {"test_stiny_bug", test_stiny_bug, TEST_CONNECTION_DEFAULT, 0, NULL , NULL},
   {"test_bug53311", test_bug53311, TEST_CONNECTION_NEW, 0, NULL , NULL},
+  {"test_conc_fraction", test_conc_fraction, TEST_CONNECTION_DEFAULT, 0, NULL , NULL},
   {NULL, NULL, 0, 0, NULL, NULL}
 };