Re: I lost my commit signature

> Jeff King venit, vidit, dixit 15.06.2016 06:34:
>> On Wed, Jun 15, 2016 at 12:27:15PM +0800, ZhenTian wrote:
>>
>>> I got two more lines from gpg -v during commit with -S:
>>> ```
>>> gpg: writing to stdout
>>> gpg: RSA/SHA1 signature from: "2EF2AD6E Tian Zhen <tianzhen@honovation.com>"
>>> ```
>>>
>>> after I commit, I push it to remote, but someone had pushed before to
>>> master branch, so I pull on master branch(`git pull --rebase`), then I
>>> check my commit via `git log --show-signature`, there is no signature
>>> in it, so I commit it with --ament and -S again, the signature is come
>>> back.
>>>
>>> I haven't check signature before push, because I have checked four
>>> commits before, every commit is fine.
>>>
>>> I don't know whether the `git pull` influenced signature or not.
>>
>> Ah, so the problem is probably that you had a signature _initially_, but
>> that it did not survive the rebase. Which makes sense, as rebase would
>> need to re-sign.  It does not by default, but you can tell it to do so
>> with "-S". Or you can set `commit.gpgsign`, which should sign in both
>> cases.
>
> While it's clear that a rebase invalidates the signature, we could try
> to be more helpful here, especially given the fact that (with our model)
> you can't sign a commit afterwards any more.
>
> commit.gpgsign signs everything, but there should be a mode for
> re-signing signed commits, or at least a warning that rebase dropped a
> signature so that you can --amend -S the last commit.
>
> Michael