Regression in 8d92fb292706 ("dir: replace exponential algorithm with a linear one")

Hello,

I admit this is somewhat of a corner case, still it happens in the reality of our admin team ... Initially this was noticed after upgrading the OS from Debian buster (with git 2.20.1) to Debian bullseye (with git 2.30.2).

(wgit is just a wrapper for git to call it from my ~/src/git.)

This is the good ("old") case:

	uwe@taurus:~/tmp/8d92fb29270$ wgit version
	git version 2.25.2.7.g0bbd0e8b5233

	uwe@taurus:~/tmp/8d92fb292706$ wgit init
	Initialized empty Git repository in /home/uwe/tmp/8d92fb292706/.git/

	uwe@taurus:~/tmp/8d92fb292706$ mkdir subdir
	uwe@taurus:~/tmp/8d92fb292706$ cd subdir/
	uwe@taurus:~/tmp/8d92fb292706/subdir$ wgit init
	Initialized empty Git repository in /home/uwe/tmp/8d92fb292706/subdir/.git/
	uwe@taurus:~/tmp/8d92fb292706/subdir$ cd ..

	uwe@taurus:~/tmp/8d92fb292706$ echo content > subdir/somefile
	uwe@taurus:~/tmp/8d92fb292706$ wgit add subdir/somefile
	uwe@taurus:~/tmp/8d92fb292706$ wgit status
	On branch master

	No commits yet

	Changes to be committed:
	  (use "git rm --cached <file>..." to unstage)
		new file:   subdir/somefile

with 8d92fb292706, the following happens:

	uwe@taurus:~/tmp/8d92fb292706$ wgit version
	git version 2.25.2.8.g8d92fb292706
	uwe@taurus:~/tmp/8d92fb292706$ wgit init
	Initialized empty Git repository in /home/uwe/tmp/8d92fb292706/.git/
	uwe@taurus:~/tmp/8d92fb292706$ mkdir subdir
	uwe@taurus:~/tmp/8d92fb292706$ cd subdir/
	uwe@taurus:~/tmp/8d92fb292706/subdir$ wgit init
	Initialized empty Git repository in /home/uwe/tmp/8d92fb292706/subdir/.git/
	uwe@taurus:~/tmp/8d92fb292706/subdir$ cd ..
	uwe@taurus:~/tmp/8d92fb292706$ echo content > subdir/somefile
	uwe@taurus:~/tmp/8d92fb292706$ wgit add subdir/somefile
	uwe@taurus:~/tmp/8d92fb292706$ wgit status
	On branch master

	No commits yet

	Untracked files:
	  (use "git add <file>..." to include in what will be committed)
		subdir/

	nothing added to commit but untracked files present (use "git add" to track)

So git after 8d92fb292706 doesn't add files from a subdirectory if said subdirectory is tracked in git, too.

While I'm not sure which of the two behaviours is the bogus one, this is a change in behaviour that I guess wasn't intended in 8d92fb292706.

Is this something that needs fixing?

Best regards Uwe