Bug#24989: The DEADLOCK error is improperly handled by InnoDB.

When innodb detects a deadlock it calls ha_rollback_trans() to rollback the 
main transaction. But such action isn't allowed from inside of triggers and
functions. When it happen the 'Explicit or implicit commit' error is thrown
even if there is no commit/rollback statements in the trigger/function. This
leads to the user confusion.

Now the convert_error_code_to_mysql() function doesn't call the 
ha_rollback_trans() function directly but rather calls the
mark_transaction_to_rollback function and returns an error.
The sp_rcontext::find_handler() now doesn't allow errors to be caught by the
trigger/function error handlers when the thd->is_fatal_sub_stmt_error flag
is set. Procedures are still allowed to catch such errors.
The sp_rcontext::find_handler function now accepts a THD handle as a parameter.
The transaction_rollback_request and the is_fatal_sub_stmt_error flags are 
added to the THD class. The are initialized by the THD class constructor.
Now the ha_autocommit_or_rollback function rolls back main transaction
when not in a sub statement and the thd->transaction_rollback_request
is set.
The THD::restore_sub_statement_state function now resets the 
thd->is_fatal_sub_stmt_error flag on exit from a sub-statement.

1 files changed, 5 insertions, 1 deletions

diff --git a/sql/sp_rcontext.h b/sql/sp_rcontext.h
index fbf479f52aa..0104b71a648 100644
--- a/sql/sp_rcontext.h
+++ b/sql/sp_rcontext.h
@@ -125,7 +125,7 @@ class sp_rcontext : public Sql_alloc
 
   // Returns 1 if a handler was found, 0 otherwise.
   bool
-  find_handler(uint sql_errno,MYSQL_ERROR::enum_warning_level level);
+  find_handler(THD *thd, uint sql_errno,MYSQL_ERROR::enum_warning_level level);
 
   // If there is an error handler for this error, handle it and return TRUE.
   bool
@@ -236,6 +236,10 @@ private:
     during execution.
   */
   bool m_return_value_set;
+  /**
+    TRUE if the context is created for a sub-statement.
+  */
+  bool in_sub_stmt;
 
   sp_handler_t *m_handler;      // Visible handlers
   uint m_hcount;                // Stack pointer for m_handler