Re: [PATCH] describe: refresh the index when 'broken' flag is used

[Abhijeet Sonar <abhijeet.nkt@gmail.com>]

> What is the reason why you want to change the owner of a file in
> your test?
>
> If it is merely to make sure you cannot write to the .git/index
> file, temporarily doing chmod of the .git directory in a test (with
POSIXPERM prerequisite) may be one way to do so, and you do not need
the second user in the system test is running.

I want to change the owner of a checked-in file and not the `.git`
directory.  This is because of what you noted in an earlier message:

> As many attributes of each file (like the
> last modified timestamp and who owns the file) are recorded in the
> index for files that were verified to be unmodified (this is done so
> that by doing lstat() on a path and comparing the result with the
> information saved in the index, we can notice that the path was
> modified without actually opening the file and looking at the
> contents), after doing something (like "git diff") that causes this
> information updated while the files appear to be owned by you

Currently, `git describe --dirty --broken` reports the working tree as
dirty if you change the owner of a file.  And as Phillip pointed out,
calling `git update-index --unmerged -q --refresh` to update the index
fixes this.

What I want to test looks something like this:

# initially, the file is owned by a non-root user
chown root file
git describe --dirty --broken  # incorrectly suffixes the output with '-dirty'

As mentioned earlier, the dirty suffix goes away if the index is
refreshed before running describe.  This is what I really want to
assert -- that there is no '-dirty' suffix when owner of a file is changed.
This kind of simulates the scenario where `git describe` is run in a
docker container as was originally reported by Paul:

> mkdir test-container
>
> cd test-container
> 
> cat >Dockerfile <<EOF
> 
> FROM docker.io/debian:bookworm-slim
> 
> WORKDIR /work
> 
> RUN apt-get update && apt-get -y install git
> 
> EOF
> 
> podman build -t test-image .
> 
> 
> 
> mkdir test-repo
> 
> cd test-repo
> 
> git init echo "Hello, world" > README
> 
> git add README
> 
> git commit -m "Initial commit" README
> 
> git tag v1.0.0
>
>
>
> git describe --tags --dirty --broken
>
>
>
> podman run -v `pwd`:/work --rm -it --entrypoint '["/usr/bin/git",
> 
>    "describe", "--tags", "--dirty", "--broken"]' test-image


Thanks