Re: Any objectsions to enhancing git-log to show tags/branch heads?

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Apr 16, 2007, 23:00 UTC
Message-ID: <Pine.LNX.4.64.0704161552160.5473@woody.linux-foundation.org>
In-Reply-To: <E1HdQah-0008Q2-7E@candygram.thunk.org>

On Mon, 16 Apr 2007, Theodore Ts'o wrote:

Show 10 quoted lines

> 
> I've recently noticed that I'm often firing up gitk for no other purpose
> than to see which changesets have which tags and branch heads.  Often
> I'll fire up gitk, quickly look at the tags/branches, and then kill it
> before it's done parsing the repository, resulting in python errors as
> it dies.
> 
> So I'm wondering why we haven't arranged to have git-log show this
> information, and whether there would be any objections if "git-log"
> showed something like this:

Ok, the next few emails will send out a series of two patches to do this.

The patches are much larger than necessary, because the way I did it was to add a totally generic notion of "object decorations", ie random data structures that can be attached to an object.

I actually stole the implementation from "object-refs", and in fact made object refs just be a normal decoration.

The exact syntax is up in the air, but with this, I can say

	git log --decorate

(we could obviously make the "--decorate" thing be the default if really wants to), and it will result in something like this:

	commit 02cfc097c2351a2b6e3a65626ce619f038f73c03 (refs/heads/master)
	Author: Linus Torvalds <torvalds@osdl.org>
	Date:   Mon Apr 16 15:49:58 2007 -0700
	
	    Add support for "commit name decorations" to log family of commands
	
	    Right now, it adds "--decorate" as a log option, which prints out the
	    ref names that point to that object if any.
	
	    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
	
	commit b1beb21820bea9c2fb9c04019c485d7810cba710 (refs/tags/test-tag)
	Author: Linus Torvalds <torvalds@osdl.org>
	Date:   Mon Apr 16 15:11:54 2007 -0700
	
	    Add a generic "object decorator" interface, and make object refs use it
	
	    This allows you to add an arbitrary "decoration" of your choice to any
	    object.  It's a space- and time-efficient way to add information to
	    arbitrary objects, especially if most objects probably do not have the
	    decoration.
	
	    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
	
	commit 7a1593972c19df26aee7d14c7d7c8c4fce24fb26 (refs/heads/parent)
	Merge: b073211... 5f2e1df...
	Author: Junio C Hamano <junkio@cox.net>
	Date:   Sun Apr 15 17:52:07 2007 -0700
	
	    Merge branch 'maint'
	....

ie notice the "decorations" after the commit name that actually tell what branch that commit is on.

A commit may obviously be on multiple branches, in which case it will have multiple decorations, and they will show up like so:

	commit 1ed91937e5cd59fdbdfa5f15f6fac132d2b21ce0 (tag: refs/tags/v1.0rc6, tag: refs/tags/v0.99.9n)

where that is an example of a commit that is tagged with two different tag objects (it's also an example of the difference of having a direct ref to it and having a ref that is a tag object that points to it: see the "refs/tags/test-tag" example above on what a *direct* tag reference will look like, while the "tag: refs/tags/xyzzy" format means that it's an *indirect* reference through a tag object.

Patches to follow.

		Linus