MySQL Bugs: #83686: Declare overridden Item member functions and final Item subclasses

Bug #83686	Declare overridden Item member functions and final Item subclasses
Submitted:	4 Nov 2016 8:11	Modified:	10 Nov 2016 19:34
Reporter:	Marko Mäkelä	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:	8.0.1	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
When virtual member functions are being renamed or replaced, it would be extremely useful if the compiler were able to warn about member functions that were intended to be overriding a member function in a base class, but are not actually overriding anything.

The C++11 override keyword would allow this.

Furthermore, the C++11 final keyword would enable some additional optimizations, and it would make the code more readable by documenting that there cannot be any classes derived from a final class.

How to repeat:
For example, in item_xmlfunc.cc, rename one of the val_nodeset() member functions to something else, and observe that no warning is generated at compilation time. The error might only be detected by a failure of ./mtr main.xml (result difference).

Suggested fix:
Add the C++11 final and override keywords to the Item classes.

Posted by developer:
 
Fixed in 8.0.1.

Code cleanup. No changelog entry needed.