Commit hash does not exist in git log

Question

I was exploring GitHub projects using git. Some things don't make sense to me.

For example in Opencv I can checkout to commit 539f065446a993825d61dddc5d9dc72ae54d7a29 (which is version 4.2.0). However when I use git rev-list --all to view the list of all commits, I don't find this hash (539f...).

Why is this the case? This is happening for many tagged commits.

If you need the hash of the tagged commit, you can use the following code snippet from this [post](https://stackoverflow.com/questions/8796522/git-tag-list-display-commit-sha1-hashes): `git show-ref --tags -d` — flaxel, Oct 18 '20 at 10:58
try following command: `git log --full-history`. look also git-docs [git-scm.com/docs/git-log](https://git-scm.com/docs/git-log) — SwissCodeMen, Oct 18 '20 at 11:10
Are you sure that `539f...` is actually a *commit* hash, and not an annotated tag object? (`git cat-file -t 539f065446a993825d61dddc5d9dc72ae54d7a29` will tell you the object's type.) — torek, Oct 18 '20 at 14:06
In my case the first commit I see with cmd: `git log --reverse --full-history -- $file` doesn't show my commit hash, but `git log --grep=pattern $file` - shows it so i'm also puzzled where my commit is getting lost in the `git log` history command ? ... — Ricky Levi, Nov 13 '22 at 11:38

score 1 · Answer 1 · answered Apr 11 '23 at 15:31

As @torek points out, in this case 539f065446a993825d61dddc5d9dc72ae54d7a29 is not a commit hash but a ref to annotated tag object (vs lightweight tags) so it is not among commits refs. For this exact opencv project

$ cat .git/refs/tags/4.2.0
539f065446a993825d61dddc5d9dc72ae54d7a29

You can see the tagged commit ref and tag's ref as @flaxel points (the second is tag's related commit hash)

$ git show-ref --tags -d
...
539f065446a993825d61dddc5d9dc72ae54d7a29 refs/tags/4.2.0
bda89a6469aa79ecd8713967916bd754bff1d931 refs/tags/4.2.0^{}
...

$ git cat-file -t 539f065446a993825d61dddc5d9dc72ae54d7a29
tag

$ git cat-file -t bda89a6469aa79ecd8713967916bd754bff1d931
commit

$ git show-ref --head
0052d46b8e33c7bfe0e1450e4bff28b88f455570 HEAD
0052d46b8e33c7bfe0e1450e4bff28b88f455570 refs/heads/master
...
539f065446a993825d61dddc5d9dc72ae54d7a29 refs/tags/4.2.0
...

Annotated tag objects have extra meta data (tagger's name, email, date, message)

$ git show 539f065446a993825d61dddc5d9dc72ae54d7a29
tag 4.2.0
Tagger: Alexander Alekhin <alexander.alekhin@intel.com>
Date:   Fri Dec 20 16:44:16 2019 +0300

OpenCV 4.2.0

commit bda89a6469aa79ecd8713967916bd754bff1d931 (tag: 4.2.0)
Author: Alexander Alekhin <alexander.alekhin@intel.com>
Date:   Fri Dec 20 16:44:16 2019 +0300

    release: OpenCV 4.2.0
...

Annotated tag can be created with

git tag -a v1.0 -m "Adding tag 1.0 (tag's message)"

Commit hash does not exist in git log

1 Answers1