Re: Notes on Using Git with Subprojects

From: Rogan Dawes <lists@dawes.za.net>
Date: Sep 27, 2006, 23:55 UTC
Message-ID: <451B0F59.6070901@dawes.za.net>
In-Reply-To: <20060927233639.GE21839@spearce.org>

Shawn Pearce wrote:

Show 10 quoted lines

> 
>  - Higher level projects should drive subprojects.
> 
>    Higher level projects tend to be composed of specific revisions or
>    specific generations of subprojects.
> 
>    Part of the content of the higher level project is just what
>    those subproject specifications are and how those subprojects
>    should appear in a working directory.
>

Show 7 quoted lines

> 
> I used the term "generation of subprojects" as not everyone wants
> to bind their root project to a specific revision of a subproject.
> Indeed that may not be entirely practical.  Instead just a particular
> lineage of development (e.g. "Version 1.0" vs. "Version 1.2")
> may be all that is needed.
>

Does it not make sense that a commit of the higher level project should include the contents of its subprojects at that particular moment in time?

e.g. using the previous example of a kernel, apache, glibc, etc

You may track the subprojects using whatever scm applies to THAT subproject. But when you want to record the state of the entire project, you want to include the state of the subprojects. So, your super-project commit would actually recurse down into the working directories of the subprojects and record the state/contents of each file that makes up each of the subprojects.

So, if someone is tracking the overall project, and they do a pull of v1.1 (tag), they will see exactly what v1.1 looked like in your repo.

What this makes me think is that it might be useful to have a mechanism for recalculating the tree-ish of a subdirectory and finding an associated commit, for the case where a subproject is also managed by git.

i.e. given a super-project in this state, and knowing that this subproject is managed by git, which revision of the subproject are we talking about, and can we find a commit that matches this tree-ish? (assuming we have the history of the subproject available, of course)

Regards,

Rogan