GH-15723: add ReflectionConstant::getFileName()

[DanielEScherzer]

Allow determining the name of the file that defined a constant, when the constant was defined in userland code via define() or const. For constants defined by PHP core or extensions, false is returned, matching the existing getFileName() methods on other reflection classes.

[dstogov]

This adds new behavior in cost of increasing each zend_constant size.
New behavior requires the RFC process and can't go into the feature frozen PHP-8.4.
Personally, I don't see significant value. On the other hand, the cost is not significant.

[janedbal]

Personally, I don't see significant value.

One of the real-world usages I'd use it for is unused composer package analysis, see current issue

[iluuu1994]

@DanielEScherzer Thank you for your PR! It's a bit late in the release process but you might still have time to consult the internals mailing list, and ask if there are any objections to adding this in 8.4.

New behavior requires the RFC process and can't go into the feature frozen PHP-8.4.

This is no longer accurate. Small feature additions have historically been allowed without requiring RFCs. It's generally understood that they are ok if announced on the ML with no objections. This is indeed vague, and I think we would benefit from specifying this process. Additionally, features are now allowed all the way up to release candidates since https://wiki.php.net/rfc/release_cycle_update.

[bwoebi]

I wonder whether it's reasonable to store the line number at the same time?

[DanielEScherzer]

I've sent an email to internals (my first one!) - https://news-web.php.net/php.internals/125571 // https://externals.io/message/125571
If this gets approved I'll deal with the merge conflict

[iluuu1994]

There have been no objections on the ML, but unfortunately it has only been posted 5 days ago. 8.4 RC1 is tagged on Tuesday, so I would suggest delaying this for 8.5.

[DanielEScherzer]

There have been no objections on the ML, but unfortunately it has only been posted 5 days ago. 8.4 RC1 is tagged on Tuesday, so I would suggest delaying this for 8.5.

Thats understandable, but annoying that this won't be included. Can we add the Waiting on RM label and see if they might be willing to include it? @php/release-managers-84

[janedbal]

How is this evolving? Any chance this gets into PHP 8.4 release? Thanks

[iluuu1994]

@janedbal No, RC1 has landed. This will be delayed to 8.5.

[DanielEScherzer]

Well, this missed 8.4, but since that has been branched I hope it can be merged for 8.5 - I've rebased to resolve the merge conflict and added an entry to UPGRADING

[iluuu1994]

It seems a bit inconsistent not to offer getStartLine (getEndLine might be overkill).

Another note: We don't have this field or getStartLine on ReflectionClassConstant. The former we can get through getDeclaringClass though.

[DanielEScherzer]

It seems a bit inconsistent not to offer getStartLine (getEndLine might be overkill).

Another note: We don't have this field or getStartLine on ReflectionClassConstant. The former we can get through getDeclaringClass though.

I'd be happy to add getStartLine, but it means that we need to track the line where every constant is declared - I figured that without someone asking for it / having a use case, it would just add extra memory to every constant PHP tracks

[iluuu1994]

Looks good, I merged this now as there were no complaints on the list. Thanks!