[BUG] git-cherry false-positive on upstream new-line change at end-of-file

From: Tilman Vogel <tilman.vogel@web.de>
Date: Jul 23, 2020, 14:42 UTC
Message-ID: <2639321.dTF8K4C05n@alien.lan>

Thank you for filling out a Git bug report! Please answer the following questions to help us understand your issue.

What did you do before the bug happened? (Steps to reproduce your issue)

I was working on two branches "master" and "feature". On "master" I "git cherry-pick feature" in order to pick the latest commit from "feature".

What did you expect to happen? (Expected behavior)

When I run "git cherry master feature" the picked commit is marked with "-".

What happened instead? (Actual behavior)

When I run "git cherry master feature" the picked commit is marked with "+".

What's different between what you expected and what actually happened?

Because the commit has just been picked, it should be marked as "-". The actual behavior claims the commit had not been picked.

Anything else you want to add:

It is important to note that the only change, I did on master after branching "feature", was to add a missing newline at the end of the file that I changed on "feature".

If I replay the same scenario with a file that has a newline at the end and I am only adding a newline at the beginning of it on master, cherry gives the expected "-" after cherry-picking.

Please see this simple example:

> git clone https://github.com/tvogel/cherry-broken.git 
> cd cherry-broken

# see broken behaviour:

> git cherry origin/master origin/feature

+ 26f77def8f1380cc3fd08ebc3f70652da79f1a2e

# check that patch-id is actually the same:

> git show --patch origin/master | git patch-id

ca5d666a572ec32bff9cec17b97d611316f89236 0725b090dd82f2e6f9949ce853778391e60b08d1

> git show --patch origin/feature | git patch-id

ca5d666a572ec32bff9cec17b97d611316f89236 26f77def8f1380cc3fd08ebc3f70652da79f1a2e

# see OK behaviour:

> git cherry origin/master-ok origin/feature-ok

- 7ce2c0ecd3024c04bcf7b78d332841b2e791e06f

In the "*-ok" branches, the file has newline at the end from the beginning and "master" only inserts a newline at the beginning of the file. "feature-ok" has the same change as "feature" (content-wise).

Please review the rest of the bug report below. You can delete any lines you don't wish to share.

[System Info] git version: git version 2.27.0 cpu: x86_64 no commit associated with this build sizeof-long: 8 sizeof-size_t: 8 uname: Linux 5.7.5-1-default #1 SMP Tue Jun 23 06:00:46 UTC 2020 (a1775d0) x86_64 compiler info: gnuc: 10.1 libc info: glibc: 2.31

[Enabled Hooks] not run from a git repository - no hooks to show