threads / discuss / 20110

git-am with an initial checkin doesn't work

Subject: git-am with an initial checkin doesn't work

## tl;dr

3 messages between Jul 14, 2009 and Jul 15, 2009.

replies: 2people: 3as markdown or json

Dirk Süsserott· Jul 14, 2009, 14:55 UTC · lore

Hi,

I've a question concerning 'git am' and 'git format-patch'. It seems impossible to apply the "initial checkin" (as generated by git format-patch -N --root) to an empty repository. The following workflow might clarify that:

# Create a new repository with an initial checkin: mkdir foo && cd foo && git init echo "initial checkin" > initial.checkin git add initial.checkin && git commit -m "initial checkin"

# Kinda "export" the repo: git format-patch -1 --root; # generates 0001-initial-checkin.patch

# Re-create the repository: rm -rf .git initial.checkin && git init

# Try to "import" the patch: git am 0001-initial-checkin.patch

The latter yields to fatal: HEAD: not a valid SHA1 fatal: bad revision 'HEAD'

It works, when I git apply 0001-initial-checkin.patch instead of am'ing it, but then the thing isn't committed and I've to manually git-commit it.

Is this a bug, intentional behavior, or am I missing some magic option to git-am?

Background: I faced that problem when I tried to import some old data into Git (namely .tar.gz files) and wanted to start with 2 or 3 commits of my own (the import scripts) and then the other files on top of it. Because my import scripts didn't work well at first, I had to re-, re-, and re-import and start over all again. To always start with a clean repo, I thought adding my scripts and then saving them as 000N-*.patch would be a good idea, but the initial git-am didn't work. I know, there are other ways (git-rebase is a big friend here), but I thought git-format-patch and git-am worked symmetrically. Wrong?

Cheers,
    Dirk

Junio C Hamano· Jul 14, 2009, 18:24 UTC · re: Dirk Süsserott · lore

Re: git-am with an initial checkin doesn't work

Dirk Süsserott <newsletter@dirk.my1.cc> writes:

Show 14 quoted lines

> # Try to "import" the patch:
> git am 0001-initial-checkin.patch
>
> The latter yields to
> fatal: HEAD: not a valid SHA1
> fatal: bad revision 'HEAD'
>
> It works, when I
> git apply 0001-initial-checkin.patch
> instead of am'ing it, but then the thing isn't committed and I've to
> manually git-commit it.
>
> Is this a bug, intentional behavior, or am I missing some magic option
> to git-am?

The original mode of operation of the e-mail patchflow commands was to support project members who contribute changes to _existing_ projects, and maintainers to accept such changes. The reason behind the behaviour you are observing is merely a historical accident that nobody bothered about use cases outside of that original purpose. For exactly the same reason, the original implementation of format-patch did not bother with the root commit.

IOW, this was not an intentional behaviour, neither it was a bug. It was simply use outside of spec, and nobody bothered until f79d4c8 (git-am: teach git-am to apply a patch to an unborn branch, 2009-04-10), which is v1.6.3-rc1~11^2, added a support for it.

What version of git are you running?

Dirk Süsserott· Jul 15, 2009, 14:46 UTC · re: Junio C Hamano · lore

Re: git-am with an initial checkin doesn't work

Am 14.07.2009 20:24 schrieb Junio C Hamano:

Show 33 quoted lines

> Dirk Süsserott <newsletter@dirk.my1.cc> writes:
> 
>> # Try to "import" the patch:
>> git am 0001-initial-checkin.patch
>>
>> The latter yields to
>> fatal: HEAD: not a valid SHA1
>> fatal: bad revision 'HEAD'
>>
>> It works, when I
>> git apply 0001-initial-checkin.patch
>> instead of am'ing it, but then the thing isn't committed and I've to
>> manually git-commit it.
>>
>> Is this a bug, intentional behavior, or am I missing some magic option
>> to git-am?
> 
> The original mode of operation of the e-mail patchflow commands was to
> support project members who contribute changes to _existing_ projects, and
> maintainers to accept such changes.  The reason behind the behaviour you
> are observing is merely a historical accident that nobody bothered about
> use cases outside of that original purpose.  For exactly the same reason,
> the original implementation of format-patch did not bother with the root
> commit.
> 
> IOW, this was not an intentional behaviour, neither it was a bug.  It was
> simply use outside of spec, and nobody bothered until f79d4c8 (git-am:
> teach git-am to apply a patch to an unborn branch, 2009-04-10), which is
> v1.6.3-rc1~11^2, added a support for it.
> 
> What version of git are you running?
> 
>

Hi Junio,

I used "1.6.1.9.g97c34" which is an msysGit release and not exactly the latest. I now updated to "1.6.3.2.1299.gee46c" and the problem dissapeared. Thanks for the hint and sorry for the noise.

     -- Dirk