STYLE: Rename ITK_DISALLOW_COPY_AND_ASSIGN to ITK_DISALLOW_COPY_AND_MOVE

[N-Dekker]

Clarifies that the macro does not just disallow copy and assign, but
also move operations. Note that in this context, the term "move" refers
to both move-construct and move-assign.

With this commit, the old macro name will remain available, as long as
ITK_FUTURE_LEGACY_REMOVE = OFF (which is the default).

[dzenanz]

This will cause another round of changes in remote modules, dependent libraries and application to update this macro. I am not sure whether this clarification is worth it.

[hjmjohnson]

I think all 3 functions should be listed in the newly named macro ITK_DISALLOW_COPY_MOVE_ASSIGN

I like the clarity. For the moment we could make the old name an alias (not legacy), but have a note to make it legacy at the next major update. This will give a long transition period for the new name.

[dzenanz]

@hjmjohnson That makes sense. For now, put under future legacy macro.

[N-Dekker]

Thanks for your feedback, Hans and Dženan.

@hjmjohnson

I think all 3 functions should be listed in the newly named macro ITK_DISALLOW_COPY_MOVE_ASSIGN

3 functions? But the macro actually deletes four of them:

1. The copy-constructor
2. The copy-assignment operator
3. The move-constructor
4. The move-assignment operator

https://github.com/InsightSoftwareConsortium/ITK/blob/v5.1.1/Modules/Core/Common/include/itkMacro.h#L358-L362

You could mention all four in a macro name, but that would then be a very long macro name. Would you like that?

Conceptually the macro disallows both copy and move, so I would still prefer to name it ITK_DISALLOW_COPY_AND_MOVE.

@dzenanz

For now, put under future legacy macro.

You mean ITK_FUTURE_LEGACY_REMOVE, right, instead of ITK_LEGACY_REMOVE?

#if !defined(ITK_FUTURE_LEGACY_REMOVE)
// Old macro name calls the new one. 
#  define ITK_DISALLOW_COPY_AND_ASSIGN(TypeName) ITK_DISALLOW_COPY_AND_MOVE(TypeName)
#endif

Would be fine to me.

[hjmjohnson]

@N-Dekker I agree with you regarding COPY_MOVE only in the name. Thanks for pointing this out.

Also good with future deprecation rather than current deprecation.

[N-Dekker]

The problem I feel about the old macro name "ITK_DISALLOW_COPY_AND_ASSIGN" isn't only about the fact that it does not mention "move". To me, the expression "disallow copy and assign" sounds like "disallow dogs and pets". Even though not all pets are dogs, and not all dogs are pets, it sounds a bit funny to me. Hope that makes some sense to you 😺

[hjmjohnson]

@N-Dekker THANKS! This is really great. Thank you for being persistent.

[blowekamp]

Using future legacy seems remove appropriate here.

[jhlegarreta]

Looks like some were left behind?
https://open.cdash.org/index.php?project=Insight
e.g.
https://open.cdash.org/viewBuildError.php?buildid=6817858

Or maybe these builds have some CMake legacy-related flags that make the itkMacro.h legacy #if block not to be taken into account?

[hjmjohnson]

@jhlegarreta See #2059