De-symlink .gitignore to mollify new Git.

[schmonz]

De-symlink .gitignore to mollify new Git.

In Git 2.32.0 and newer, git status (for instance) says:

warning: unable to access '.gitignore': Too many levels of symbolic links

https://github.com/git/git/blob/master/Documentation/RelNotes/2.32.0.txt
explains thus:

* It does not make sense to make ".gitattributes", ".gitignore" and
  ".mailmap" symlinks, as they are supposed to be usable from the
  object store (think: bare repositories where HEAD:.mailmap etc.
  are used). When these files are symbolic links, we used to read
  the contents of the files pointed by them by mistake, which has
  been corrected.

To satisfy Git, turn .gitignore back into a regular file containing the
contents of TARGETS. To satisfy other uses of TARGETS (such as in
exported tar archives, which don't include .gitignore), keep it as a
regular in-tree file too, with reminders in each to sync with the other.

[DerDakon]

This will break the generated tar archives as .git* is ignored in .gitattributes.

[DerDakon]

And now we are autogenerating targets. Fine with me, but maybe we can take the step and clean up this ancient construct. .gitignore may just filter *.o, while TARGETS could simply be generated by grepping the objects from Makefile if it is generated anyway. Similar things may happen for other targets. If we open that door we should walk through it, not only peek inside.

[schmonz]

Agree with going further, but only after the magical inflection point where people no longer need to apply the major patches so we can willingly break whatever minor patches they may have left.

[DerDakon]

I agree with that for TARGETS to a degree (see below), but for .gitignore we are not bound to anything.

TARGETS is just historic debt in my eyes. The only thing it is needed for is make clean, which isn't that important anyway. And if we are going to extract the target list from make it into a variable, and use that for both make it and make clean I doubt we have much left beyond *.o and *.a. And then we could tell people to simply ignore any failures in TARGETS.

But this is indeed the next step, which we could am for 1.10 or something like that, and now just make things work again. And for the time being let's just keep the files identical, i.e. without the "autogenerated" header. This way we don't needlessly duplicate things in git, noone cares if that is autogenerated in a release tarball (and there it is not even true not to touch it), and eventually we can just kill the whole thing with fire.

[DerDakon]

I fear this will become endless… sorry for that.

Have you tried this with a release tarball? I bet not, and I have neither ;)

But now TARGETS is part of it. TARGETS is there, make will try to refresh it, but there is no rule to make .gitignore, required from TARGETS or something like that. As I said, I have not tried, but I bet this will happen.

Maybe we should just add a make tarball or something that includes the git archive … command from the wiki, and which depends on TARGETS, and will error out if git status is not clean afterwards. And when we are at it, maybe add make TARGETS and a git status check to CI so we can easily catch when someone forgets it.

[DerDakon]

Good enough for 1.09, let's do it much better afterwards.

[jlmuir]

LGTM.