Re: Bug Report: Subtrees and GPG Signed Commits

> On Tue, Jan 30, 2018 at 6:24 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Stefan Beller <sbeller@google.com> writes:
>>> There has not been feedback for a while on this thread.
>>> I think that is because subtrees are not in anyone's hot
>>> interest area currently.
>>>
>>> This is definitely the right place to submit&discuss bugs.
>>> Looking through "git log --format="%ae %s" -S subtree",
>>> it seems as if Avery (apenwarr@gmail.com) was mostly
>>> interested in developing subtrees, though I think he has
>>> moved on. Originally it was invented by Junio, who is
>>> the active maintainer of the project in 68faf68938
>>> (A new merge stragety 'subtree'., 2007-02-15)
>>
>> Thanks for trying to help, but I have *NOTHING* to do with the "git
>> subtree" subcommand (and I personally have no interest in it).  What
>> I did was a subtree merge strategy (i.e. "git merge -s subtree"),
>> which is totally a different thing.
>>
>> David Greene offered to take it over in 2015, and then we saw some
>> activity by David Aguilar in 2016, but otherwise the subcommand from
>> contrib/ has pretty much been dormant these days.
>
> Strictly speaking, the 'git subtree' command does in fact use 'git
> merge -s subtree' under the covers, so Junio is at least partly
> responsible for giving me the idea :)
>
> I actually have never looked into how signed commits work and although
> I still use git-subtree occasionally (it hasn't needed any
> maintenance, for my simple use cases), I have never used it with
> signed commits.
>
> git-subtree maintains a cache that maps commit ids in the "original
> project" with their equivalents in the "merged project."  If there's
> something magic about how commit ids work with signed commits, I could
> imagine that causing the "no a valid object name" problems.  Or,
> git-subtree in --squash mode actually generates new commit objects
> using some magic of its own.  If it were to accidentally copy a
> signature into a commit that no longer matches the original, I imagine
> that new object might get rejected.
>
> Unfortunately I don't have time to look into it.  The git-subtree code
> is pretty straightforward, though, so if Stephen has an hour or two to
> look deeper it's probably possible to fix it up.  The tool is not
> actually as magical and difficult as it might seem at first glance :)
>
> Sorry I can't help more.
>
> Good luck,
>
> Avery