Re: [GIT PULL] MM updates for 7.0-rc1

[Linus Torvalds]

Bah, I keep noticing these things too late, and have to fix them up
separately, but let's keep edumacating people about this issue...

On Wed, 11 Feb 2026 at 19:23, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Lorenzo Stoakes (20):
>       selftests/mm: remove virtual_address_range test

When removing rules for generating files, PLEASE DO NOT REMOVE THE
.gitignore ENTRY!

Removing the rule for generating the file does not magically then make
the file itself disappear in a purple puff of smoke.

That's just not how reality works. The past still exists.

And that means that the old generated file still exists for people,
and it has *NOT* suddenly become so supremely interesting that people
should no longer ignore it.

So when you remove a rule for generating a file (or you move it to a
different directory, or rename it, or whatever), that gitignore entry
for the old file - or old location - should stay around.

This is more than a "keep git status happy" issue. This has caused
real issues in the past, where careless developers didn't notice, and
mistakenly added stale generated binaries to their commits.

No, people shouldn't do that either, and it's a sign of being too
careless and not looking at what you commit very carefully.

But mistakes happen, and the other side of that argument is that we
sure as heck shouldn't have files suddenly appear in the source tree
because they aren't properly ignored any more.

And I'm sure this has happened many times without me noticing, but
I'll keep harping on this when I _do_ notice, because people need to
realize that .gitignore files are very much about state being left
around by the build system.

So you *add* files to the .gitignore files, but you don't remove them.
Not for a long while, at least - people keep their build trees around
for months (or years) and don't necessarily clean them up very often.

(And yes, we do have a "remove-stale-files" script that is intended to
deal with some of this, but it hasn't worked very well, and if you
want to remove stale files I'd suggest you just do "git clean -dqtx"
after you are really *really* sure that you don't have any interesting
files in your source tree that weren't tracked by git)

              Linus