hook to get info on commit, and include that in a file that is part of the commit

> Is there any way using a git hook to get info on the commit (id,
> message), put that in a file, and include that file in the commit?
> 
> If I try that in a pre-commit hook I do not get the info on the
> current commit. I tried it in pre-receive but it does not seem to get
> executed at all.

>
> On Mon, Feb 04, 2019 at 08:36:10PM -0500, Larry Martell wrote:
> > Is there any way using a git hook to get info on the commit (id,
> > message), put that in a file, and include that file in the commit?
> >
> > If I try that in a pre-commit hook I do not get the info on the
> > current commit. I tried it in pre-receive but it does not seem to get
> > executed at all.
>
> You cannot include a file in the commit with that commit's ID.
>
> The object ID of a commit is based on the data it contains, which is in
> turn based on the data in its top-level tree, which is in turn based on
> the data in all of its trees and blobs. If you add or change a file in a
> commit (or the message of that commit), you necessarily result in that
> commit having a different object ID. This is by design and is valuable
> for checking the integrity of the history.
>
> Furthermore, the hooks for a commit are designed for checking and
> notification, not for editing the commit, with the exception of the
> commit message hooks, which are designed only for editing the commit
> message, not the contents.
>
> The pre-receive hook runs on the server side, so if you aren't running
> it there, then it won't get called at all.

> Thanks for the reply. Any suggestions on how to achieve what I want to do?
> 
> The use case is that we want to have a file that is part of the
> install that has certain info (commit id, date of commit, commit
> message, etc.). and we'd like that to be generated automatically.

>
> On Mon, Feb 04, 2019 at 09:00:42PM -0500, Larry Martell wrote:
> > Thanks for the reply. Any suggestions on how to achieve what I want to do?
> >
> > The use case is that we want to have a file that is part of the
> > install that has certain info (commit id, date of commit, commit
> > message, etc.). and we'd like that to be generated automatically.
>
> If you want to generate a file, you can certainly do that in the
> post-commit hook or using a Makefile target. You just can't check it
> into the repo. Lots of projects do this as part of their build process.
>
> An example of what you could do is "git log --pretty='tformat:%H%n%B' HEAD".
> That will print the commit hash and commit message to standard output
> for each commit. If you want just one commit, you can use "-1".

> On Mon, Feb 4, 2019 at 9:15 PM brian m. carlson
> <sandals@crustytoothpaste.net> wrote:
> > If you want to generate a file, you can certainly do that in the
> > post-commit hook or using a Makefile target. You just can't check it
> > into the repo. Lots of projects do this as part of their build process.
> >
> > An example of what you could do is "git log --pretty='tformat:%H%n%B' HEAD".
> > That will print the commit hash and commit message to standard output
> > for each commit. If you want just one commit, you can use "-1".
> 
> Yeah, but I want it part of the repo so it makes it to the target system.

>
> On Mon, Feb 04, 2019 at 09:18:14PM -0500, Larry Martell wrote:
> > On Mon, Feb 4, 2019 at 9:15 PM brian m. carlson
> > <sandals@crustytoothpaste.net> wrote:
> > > If you want to generate a file, you can certainly do that in the
> > > post-commit hook or using a Makefile target. You just can't check it
> > > into the repo. Lots of projects do this as part of their build process.
> > >
> > > An example of what you could do is "git log --pretty='tformat:%H%n%B' HEAD".
> > > That will print the commit hash and commit message to standard output
> > > for each commit. If you want just one commit, you can use "-1".
> >
> > Yeah, but I want it part of the repo so it makes it to the target system.
>
> You can create an additional commit for each commit that you put in with
> the additional file, or you can serialize it as a note for the commit
> (using git notes), which can then be pushed to the remote server by
> pushing refs/notes/commits.
>
> I'm not aware of any other way to do what you want.