MDEV-24176 Server crashes after insert in the table with virtualbb-10.3-midenok-MDEV-24176MDEV-24176/10.3_old

column generated using date_format() and if()

When table is reopened from cache vcol_info contains stale
expression. We refresh expression via TABLE::vcol_fix_exprs() but
first we must prepare a proper context (Vcol_expr_context) and do some
preparations which meet some requirements:

1. fields must not be fixed, we unfix them with cleanup() via
cleanup_processor.

2. Item_ident must have cached_table cleared. Again, this is stale
data which was already freed. cached_table interferes with
find_field_in_tables().

We cannot clear cached_table directly in Item_ident::cleanup()
method. Lots of spaghetti logic depends on cached_table existence even
after cleanup() done.

3. If Item_ident has table_name non-NULL we trigger expr update. That
is done via Item_ident::check_vcol_func_processor() and
VCOL_TABLE_ALIAS flag.

(4-7) The below conditions are prepared by Vcol_expr_context and used in
both fix_session_expr_for_read() and TABLE::vcol_fix_exprs():

4. Any fix_expr() must be done on expr_arena as there may be new items
created. It was a bug in fix_session_expr_for_read(). It was just not
reproduced because there were no second refix. Now refix is done for
more cases so it does reproduce. Tests affected: vcol.binlog

5. Also name resolution context must be narrowed to the single table
with all crutches in place. Tests affected: vcol.update

6. sql_mode must be clean and not fail expr update.

sql_mode such as MODE_NO_BACKSLASH_ESCAPES, MODE_NO_ZERO_IN_DATE, etc
must not affect vcol expression update. If the table was created
successfully any further evaluation must not fail. Tests affected:
main.func_like

7. Warnings are disabled during expr update. It is assumed that these
warnings were printed before during initialization phase or later
during execution phase. Tests affected: vcol.wrong_arena

Dictionary: refresh, update and refix are the synonyms for
vcol_fix_exprs() or fix_session_expr_for_read() calls.

8. cleanup_excluding_fields_processor() removed. It was just a quick
hack to exclude wrongly working Item_field from processing. Now it
works due to correct execution environment (see next commit). Related
to MDEV-10355.

1 files changed, 19 insertions, 0 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 133c0f6fec5..fe42909aa0a 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1831,6 +1831,25 @@ private:
 };
 
 
+struct Silence_warnings : public Internal_error_handler
+{
+public:
+  virtual bool handle_condition(THD *,
+                                uint,
+                                const char* sqlstate,
+                                Sql_condition::enum_warning_level *level,
+                                const char* msg,
+                                Sql_condition ** cond_hdl)
+  {
+    *cond_hdl= NULL;
+    if (*level == Sql_condition::WARN_LEVEL_WARN)
+      return TRUE;
+
+    return FALSE;
+  }
+};
+
+
 /**
   Internal error handler to process an error from MDL_context::upgrade_lock()
   and mysql_lock_tables(). Used by implementations of HANDLER READ and