Bug#31800: Date comparison fails with timezone and slashes for greater than comparison

BETWEEN was more lenient with regard to what it accepted as a DATE/DATETIME
in comparisons than greater-than and less-than were. ChangeSet makes < >
comparisons similarly robust with regard to trailing garbage (" GMT-1")
and "missing" leading zeros. Now all three comparators behave similarly
in that they throw a warning for "junk" at the end of the data, but then
proceed anyway if possible. Before < > fell back on a string- (rather than
date-) comparison when a warning-condition was raised in the string-to-date
conversion. Now the fallback only happens on actual errors, while warning-
conditions still result in a warning being to delivered to the client.


mysql-test/r/select.result:
  Show that we compare DATE/DATETIME-like strings as date(time)s
  now, rather than as bin-strings.
  Adjust older result as "2005-09-3a" is now correctly seen as
  "2005-09-3" + trailing garbage, rather than as "2005-09-30".
mysql-test/t/select.test:
  Show that we compare DATE/DATETIME-like strings as date(time)s
  now, rather than as bin-strings.
sql-common/my_time.c:
  correct/clarify date-related comments, particulary for check_date().
  doxygenize comment while at it.
sql/item_cmpfunc.cc:
  get_date_from_str() no longer signals an error when all we had
  was a warning-condition -- and one we already gave the user a
  warning for at that. Preamble doxygenized.

1 files changed, 17 insertions, 17 deletions

diff --git a/sql-common/my_time.c b/sql-common/my_time.c
index 3c08db6bf97..453c7b73008 100644
--- a/sql-common/my_time.c
+++ b/sql-common/my_time.c
@@ -54,24 +54,24 @@ uint calc_days_in_year(uint year)
           366 : 365);
 }
 
-/*
-  Check datetime value for validity according to flags.
-
-  SYNOPSIS
-    check_date()
-      ltime          Date to check.
-      not_zero_date  ltime is not the zero date
-      flags          flags to check
-      was_cut        set to 2 if value was truncated.
-		     NOTE: This is not touched if value was not truncated
-  NOTES
-    Here we assume that year and month is ok !
+/**
+  @brief Check datetime value for validity according to flags.
+
+  @param[in]  ltime          Date to check.
+  @param[in]  not_zero_date  ltime is not the zero date
+  @param[in]  flags          flags to check
+                             (see str_to_datetime() flags in my_time.h)
+  @param[out] was_cut        set to 2 if value was invalid according to flags.
+                             (Feb 29 in non-leap etc.)  This remains unchanged
+                             if value is not invalid.
+
+  @details Here we assume that year and month is ok!
     If month is 0 we allow any date. (This only happens if we allow zero
     date parts in str_to_datetime())
     Disallow dates with zero year and non-zero month and/or day.
 
-  RETURN
-    0  ok
+  @return
+    0  OK
     1  error
 */
 
@@ -117,9 +117,9 @@ my_bool check_date(const MYSQL_TIME *ltime, my_bool not_zero_date,
                         TIME_NO_ZERO_IN_DATE	Don't allow partial dates
                         TIME_NO_ZERO_DATE	Don't allow 0000-00-00 date
                         TIME_INVALID_DATES	Allow 2000-02-31
-    was_cut             0	Value ok
+    was_cut             0	Value OK
 			1       If value was cut during conversion
-			2	Date part was within ranges but date was wrong
+			2	check_date(date,flags) considers date invalid
 
   DESCRIPTION
     At least the following formats are recogniced (based on number of digits)
@@ -1087,7 +1087,7 @@ int my_TIME_to_str(const MYSQL_TIME *l_time, char *to)
       flags      - flags to use in validating date, as in str_to_datetime()
       was_cut    0      Value ok
                  1      If value was cut during conversion
-                 2      Date part was within ranges but date was wrong
+                 2      check_date(date,flags) considers date invalid
 
   DESCRIPTION
     Convert a datetime value of formats YYMMDD, YYYYMMDD, YYMMDDHHMSS,