Re: Associating tags with changelogs

From: Shawn O. Pearce <spearce@spearce.org>
Date: May 5, 2008, 04:06 UTC
Message-ID: <20080505040646.GK29038@spearce.org>
In-Reply-To: <218b69370805042040h66d02979jac6bd64456a9d304@mail.gmail.com>

Zack Brown <zacharyb@gmail.com> wrote:

Show 8 quoted lines

> I'm using git to extract changelog entries into a MySQL database, and
> I want to be able to associate each changelog with the official
> release in which it first appears. [...]
> 
> My script keeps track of the most recent changelog entry that it has
> processed into the MySQL database, so the next time it runs, it picks
> up from that entry, using "`git-log sha1string.. --pretty=fuller", and
> inserts only the changelogs since that entry into the database.

...

> Is there a command to do that? I don't see anything in the man pages for it.

No, not really. The way to do this is either invoke `git describe --contains $sha1` for each commit, or to keep track of it yourself in the script.

The algorithm is really simple, especially if you have something like Math::BigInt in Perl. Make a list of all tags, assign a bit to each tag, make a hash of commits to BigInt (bitset of tags that contain the commit).

Then run `git rev-list --all --parents --not sha1string` (where sha1string is the last commit you added to the database) and copy the bits of each commit onto its parents until the end of input.

Later loop through those commits again. If a commit's parent has a color for a tag but the commit doesn't have that tag, then that tag is the first time the commit appeared in a tag.

-- 
Shawn.