gpg "failed to write commit object"

Question

I'm trying to enable commit signing on OS X Mojave.

git commit -S -am "Test"

The error is:

error: gpg failed to sign the data
fatal: failed to write commit object

What I tried:

gpg works fine (see below), did not install gpg1 or gpg2
Installed GPG KeyChain and added a new key (even added a separate sign-only subkey whithin)
Installed pinentry
gpg2 --clearsign works fine (generates a new .asc file for files, outputs text for plain text)

Questions I looked into and tried every option:

What am I doing wrong?

if you are looking to get added to a repo instead of init git-crypt in your repo, youll need to let someone who already has access to the encrypted files to add your public key to the `/.git-crypt/...` part of the repo — mewc, May 06 '20 at 03:22
Thanks @mewc, but that was not the case, see my own answer below — Alex Buznik, May 06 '20 at 10:20
Cool, more of an fyi for the next person. Didnt feel it deserved its own answer. — mewc, May 07 '20 at 00:59

score 59 · Answer 1 · edited Aug 10 '19 at 19:25

59

I also had this problem. I found a good solution. Just try to sign a file before you commit.

$ touch a.txt
$ gpg --sign a.txt

Then, the OS will let you input the password. If this step is OK, now you can commit by signing correctly.

edited Aug 10 '19 at 19:25

Wasi

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answered Aug 10 '19 at 14:21

mkckr0

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Thanks, it saved me a lot of time! – dgebert Feb 19 '21 at 10:49
4

But why is this needed? – Koray Tugay Jul 07 '21 at 03:06
This worked, but why this has to be done? Is this a bug? – pradpi Oct 04 '21 at 11:00
1

Thanks! This helped me figure out the true issue: my terminal window was too small to render the password prompt. It seems like `git` sometimes hides the error information from surfacing. – TheLandolorien Jan 24 '22 at 21:58
Brilliant, saved me the trouble of doing all of this: https://stackoverflow.com/questions/39494631/gpg-failed-to-sign-the-data-fatal-failed-to-write-commit-object-git-2-10-0 – PaulIsLoud May 05 '22 at 07:24
Hello from 2022! Thank you very much for this answer! – Andrei Kulik Oct 16 '22 at 09:06
This is needed if you've set a passphrase! – Oliver Tappin May 15 '23 at 17:13

score 21 · Answer 2 · edited Aug 19 '19 at 02:59

21

I just added the key ID to the global config

list all keys:

gpg --list-keys

Select the one you added to github and set it.

git config --global user.signingkey [public key ID]

edited Aug 19 '19 at 02:59

MewX

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answered Jul 08 '19 at 15:39

Zacbe Gonzalez

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score 3 · Accepted Answer · answered Mar 07 '19 at 07:08

3

Heh, of course, right after I posted this question, I found the solution.

So my problem was that I followed this doc: https://help.github.com/en/articles/telling-git-about-your-signing-key

And set up both GPG and smimesign, when I have Git < 2.19 and no proper X.509 keys.

So I just removed the part with smimesign from global ~/.gitconfig

answered Mar 07 '19 at 07:08

Alex Buznik

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Exact solution for could not find the user id in specified key while commiting – Sasi Dhivya Aug 16 '21 at 16:36

score 2 · Answer 4 · answered Feb 26 '22 at 16:43

Try with echo "foobar" | gpg --clearsign. It should ask for your key's passphrase and return the signature. If instead you see the following error message:

error: gpg failed to sign the data
fatal: failed to write commit object

You might want to try running export GPG_TTY=$(tty). If after testing again you're prompted for the password and it works, run this everytime on startup, adding it to ~/.bashrc, which is actually required according to gpg-agent's documentation, as mentioned in this dev.gnupg thread and which you can verify with man gpg-agent.

I also found this gitHub gist very useful.

score 2 · Answer 5 · answered Jul 15 '22 at 12:16

2

To prompt you to enter a PIN or passphrase when required, install pinentry-mac

$ brew install pinentry-mac
$ echo "pinentry-program $(which pinentry-mac)" >> ~/.gnupg/gpg-agent.conf
$ killall gpg-agent

answered Jul 15 '22 at 12:16

Rohit

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score 1 · Answer 6 · answered Mar 05 '23 at 20:54

At least, that error message will be clearer:

Error messages given upon a signature verification failure used to discard the errors from underlying gpg program, which has been corrected with Git 2.40 (Q1 2023).

See commit ad6b320, commit 8300d15 (15 Feb 2023) by Johannes Schindelin (dscho).
^{(Merged by Junio C Hamano -- gitster -- in commit 38a227b, 24 Feb 2023)}

gpg: do show gpg's error message upon failure

^{Signed-off-by: Johannes Schindelin}

There are few things more frustrating when signing a commit fails than reading a terse "error: gpg failed to sign the data" message followed by the unsurprising "fatal: failed to write commit object" message.

In many cases where signing a commit or tag fails, gpg actually said something helpful, on its stderr, and Git even consumed that, but then keeps mum about it.

Teach Git to stop withholding that rather important information.

gpg "failed to write commit object"

6 Answers6

`gpg`: do show gpg's error message upon failure

Linked

gpg "failed to write commit object"

6 Answers6

gpg: do show gpg's error message upon failure

Linked

`gpg`: do show gpg's error message upon failure