MDEV-11839 move value caching from get_datetime_value to fix_fields time

Refactor get_datetime_value() not to create Item_cache_temporal(),
but do it always in ::fix_fields() or ::fix_length_and_dec().

Creating items at the execution time doesn't work very well with
virtual columns and check constraints that are fixed and executed
in different THDs.

mysql-test/r/cache_temporal_4265.result

@@ -7,7 +7,6 @@ a
 2002-03-04
 Warnings:
 Note	1003	2000-01-01
-Note	1003	2000-01-06
 set debug_dbug='';
 drop table t1;
 create table t1 (id int not null, ut timestamp(6) not null);

mysql-test/r/case.result

@@ -403,3 +403,37 @@ DROP TABLE t1;
 #
 # End of 10.1 test
 #
+select case 'foo' when time'10:00:00' then 'never' when '0' then 'bug' else 'ok' end;
+case 'foo' when time'10:00:00' then 'never' when '0' then 'bug' else 'ok' end
+ok
+Warnings:
+Warning	1292	Truncated incorrect time value: 'foo'
+select 'foo' in (time'10:00:00','0');
+'foo' in (time'10:00:00','0')
+0
+Warnings:
+Warning	1292	Truncated incorrect time value: 'foo'
+create table t1 (a time);
+insert t1 values (100000), (102030), (203040);
+select case 'foo' when a then 'never' when '0' then 'bug' else 'ok' end from t1;
+case 'foo' when a then 'never' when '0' then 'bug' else 'ok' end
+ok
+ok
+ok
+Warnings:
+Warning	1292	Truncated incorrect time value: 'foo'
+Warning	1292	Truncated incorrect time value: 'foo'
+Warning	1292	Truncated incorrect time value: 'foo'
+select 'foo' in (a,'0') from t1;
+'foo' in (a,'0')
+0
+0
+0
+Warnings:
+Warning	1292	Truncated incorrect time value: 'foo'
+Warning	1292	Truncated incorrect time value: 'foo'
+Warning	1292	Truncated incorrect time value: 'foo'
+drop table t1;
+select case '20:10:05' when date'2020-10-10' then 'never' when time'20:10:5' then 'ok' else 'bug' end;
+case '20:10:05' when date'2020-10-10' then 'never' when time'20:10:5' then 'ok' else 'bug' end
+bug

mysql-test/r/range.result

@@ -1595,8 +1595,6 @@ NULL
 Warnings:
 Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
 Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
-Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
-Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
 SELECT str_to_date('2007-10-00', '%Y-%m-%d') BETWEEN '' AND '2007/10/20';
 str_to_date('2007-10-00', '%Y-%m-%d') BETWEEN '' AND '2007/10/20'
 1

mysql-test/r/range_mrr_icp.result

@@ -1597,8 +1597,6 @@ NULL
 Warnings:
 Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
 Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
-Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
-Warning	1411	Incorrect datetime value: '2007-20-00' for function str_to_date
 SELECT str_to_date('2007-10-00', '%Y-%m-%d') BETWEEN '' AND '2007/10/20';
 str_to_date('2007-10-00', '%Y-%m-%d') BETWEEN '' AND '2007/10/20'
 1

mysql-test/t/case.test

@@ -287,3 +287,22 @@ DROP TABLE t1;
 --echo #
 --echo # End of 10.1 test
 --echo #
+
+#
+# caching of first argument in CASE/IN for temporal types
+#
+#
+
+# should not convert all values to time
+select case 'foo' when time'10:00:00' then 'never' when '0' then 'bug' else 'ok' end;
+select 'foo' in (time'10:00:00','0');
+
+create table t1 (a time);
+insert t1 values (100000), (102030), (203040);
+# only one warning, TIME('foo') should be cached
+select case 'foo' when a then 'never' when '0' then 'bug' else 'ok' end from t1;
+select 'foo' in (a,'0') from t1;
+drop table t1;
+
+# first comparison should be as date, second as time
+select case '20:10:05' when date'2020-10-10' then 'never' when time'20:10:5' then 'ok' else 'bug' end;

sql/item.cc

@@ -9361,13 +9361,16 @@ void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
   switch (res_type) {
   case TIME_RESULT:
   {
-    bool is_null;
-    Item **ref_copy= ref;
-    /* the following call creates a constant and puts it in new_item */
     enum_field_types type= item->field_type_for_temporal_comparison(comp_item);
-    get_datetime_value(thd, &ref_copy, &new_item, type, &is_null);
-    if (is_null)
+    longlong value= item->val_temporal_packed(type);
+    if (item->null_value)
       new_item= new (mem_root) Item_null(thd, name);
+    else
+    {
+      Item_cache_temporal *cache= new (mem_root) Item_cache_temporal(thd, type);
+      cache->store_packed(value, item);
+      new_item= cache;
+    }
     break;
   }
   case STRING_RESULT:
@@ -9702,8 +9705,7 @@ Item_cache_temporal::Item_cache_temporal(THD *thd,
 longlong Item_cache_temporal::val_datetime_packed()
 {
   DBUG_ASSERT(fixed == 1);
-  if (Item_cache_temporal::field_type() == MYSQL_TYPE_TIME)
-    return Item::val_datetime_packed(); // TIME-to-DATETIME conversion needed
+  DBUG_ASSERT(Item_cache_temporal::field_type() != MYSQL_TYPE_TIME);
   if ((!value_cached && !cache_value()) || null_value)
   {
     null_value= TRUE;
@@ -9716,8 +9718,7 @@ longlong Item_cache_temporal::val_datetime_packed()
 longlong Item_cache_temporal::val_time_packed()
 {
   DBUG_ASSERT(fixed == 1);
-  if (Item_cache_temporal::field_type() != MYSQL_TYPE_TIME)
-    return Item::val_time_packed(); // DATETIME-to-TIME conversion needed
+  DBUG_ASSERT(Item_cache_temporal::field_type() == MYSQL_TYPE_TIME);
   if ((!value_cached && !cache_value()) || null_value)
   {
     null_value= TRUE;
@@ -9775,18 +9776,26 @@ double Item_cache_temporal::val_real()
 }
 
 
-bool  Item_cache_temporal::cache_value()
+bool Item_cache_temporal::cache_value()
 {
   if (!example)
     return false;
-
   value_cached= true;
- 
+
   MYSQL_TIME ltime;
-  if (example->get_date_result(&ltime, 0))
-    value=0;
-  else
+  uint fuzzydate= TIME_FUZZY_DATES | TIME_INVALID_DATES;
+  if (Item_cache_temporal::field_type() == MYSQL_TYPE_TIME)
+    fuzzydate|= TIME_TIME_ONLY;
+
+  value= 0;
+  if (!example->get_date_result(&ltime, fuzzydate))
+  {
+    if (ltime.time_type == MYSQL_TIMESTAMP_TIME &&
+        !(fuzzydate & TIME_TIME_ONLY) &&
+        convert_time_to_datetime(current_thd, &ltime, fuzzydate))
+      return true;
     value= pack_time(&ltime);
+  }
   null_value= example->null_value;
   return true;
 }
@@ -9806,11 +9815,15 @@ bool Item_cache_temporal::get_date(MYSQL_TIME *ltime, ulonglong fuzzydate)
   ltime->time_type= mysql_type_to_time_type(field_type());
   if (ltime->time_type == MYSQL_TIMESTAMP_TIME)
   {
-    ltime->hour+= (ltime->month*32+ltime->day)*24;
-    ltime->month= ltime->day= 0;
+    if (fuzzydate & TIME_TIME_ONLY)
+    {
+      ltime->hour+= (ltime->month*32+ltime->day)*24;
+      ltime->month= ltime->day= 0;
+    }
+    else if (convert_time_to_datetime(current_thd, ltime, fuzzydate))
+      return true;
   }
   return 0;
-
 }