Re: Unfortunate interaction between git diff-index and fakeroot

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 7, 2017, 15:31 UTC
Message-ID: <xmqqzi6ueern.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <0190ae30-b6c8-2a8b-b1fb-fd9d84e6dfdf@oracle.com>

Elazar Leibovich <elazar.leibovich@oracle.com> writes:

Show 5 quoted lines

> We noticed some unexpected behavior of git, when running git commands under
> fakeroot, and then running another command without fakeroot.
>
> When running, e.g., git status, or git describe --dirty, git can
> update the index file.

Correct. fakeroot would report that the files that are actually owned by the user who is running fakeroot are owned by root; the cached stat information in the index would be "corrected" to say that they are owned by root. So once the index is refreshed like so, things will become consistent.

> The unexpected result is:
>
> "fakeroot git status" updates the index, and the index now says all files
> are owned by uid:0.

You should learn to expect it; that is how fakeroot works.

> "git diff-index --name-only HEAD" is used to test if the git tree is dirty
> without fakeroot, concluding all files have changed, since their owner UID
> is changed.

The lower-level plumbing diff-* commands are meant to be used by scripts that refresh the index once upfront.

If you are using "diff-index" for the "is the tree dirty?" check without running "update-index --refresh", then you are not using the command correctly.