Trouble with cat-file on tags
Hi,
I was trying to use cat-file to get the hash of a tag object (not the hash of the commit object the tag points to), and I'm running into some issues. At the example of a cloned gerry [1] repository:
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$ git tag test-tag
$ git tag -l test-tag v0.0.3 v0.0.4 v0.1.0 v0.1.1 v0.1.2
$ git cat-file tag refs/tags/test-tag fatal: git cat-file refs/tags/test-tag: bad file ---8<---
So for a newly created local tag, cat-file does not seem to work. However:
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$ git cat-file tag refs/tags/v0.1.2 object 91b0d21eba039e5ba0a90104c9c485735576dcbf type commit tag v0.1.2 tagger Travis Truman <[email protected]> 1452693317 -0500
Version 0.1.2
---8<---
For an existing tag, git-file suddenly *does* seem to work, although I'm puzzled why I'm getting info on the commit object here. I thought "cat-file tag" should explicitly make "cat-file" list information about the tag object itself, not about the commit object the tag points to.
Thoughts?
[1] https://github.com/trumant/gerry
Regards,
Sebastian
Quoted 11 lines · Sebastian Schuberth
---8<---
$ git tag test-tag$ git tag -l test-tag v0.0.3 v0.0.4 v0.1.0 v0.1.1 v0.1.2
Quoted 3 lines
$ git cat-file tag refs/tags/test-tag fatal: git cat-file refs/tags/test-tag: bad file ---8<---
Alright, I just found out why that is: Lighweight tags are not stored as Git objects. As soon as I make it an annoted tag by specifying a message, "cat-file tag" do esnot display a fatal error anymore.
However, I still get information about the commit oject iintsead of the tag object. Is this expected?
Regards,
Sebastian
Quoted 2 lines · Sebastian Schuberth
However, I still get information about the commit oject iintsead of the tag object. Is this expected?
Solved this one, too: Yes it is. I was misreading the docs:
"If <type> is specified, the raw (though uncompressed) contents of the <object> will be returned."
This means
$ git cat-file tag refs/tags/v0.1.2
displays the *contents* of the tag, not the tag itself. Which leads me to the next question: For a given name of an annotated tag, how to get the hash of the tag object? The solution I found for now:
$ git show-ref --tags -- v0.1.2 92b67e2b0626519ef8cd4e9cacb2bdafba6d53f0 refs/tags/v0.1.2
Regards,
Sebastian
Quoted 5 lines · Sebastian Schuberth
This means
$ git cat-file tag refs/tags/v0.1.2displays the *contents* of the tag, not the tag itself.
Right. cat-file is about looking at object content.
Quoted 6 lines
Which leads me to
the next question: For a given name of an annotated tag, how to get the hash of the tag object? The solution I found for now:$ git show-ref --tags -- v0.1.2 92b67e2b0626519ef8cd4e9cacb2bdafba6d53f0 refs/tags/v0.1.2
Here you just want to resolve the ref, without looking at the object. The canonical way is:
git rev-parse --verify v0.1.2
You can also use that to peel the tag to a commit, or a commit to a tree (e.g., with "v0.1.2^{commit}").
-Peff