Re: Following renames

On Sun, Mar 26, 2006 at 12:07:17PM +0200, Petr Baudis wrote:

Dear diary, on Sun, Mar 26, 2006 at 05:19:50AM CEST, I got a letter
where Linus Torvalds [off-list ref] said that...

quoted

On Sun, 26 Mar 2006, Petr Baudis wrote:

quoted

  In [1], Linus suggests a non-core solution. Unfortunately, it doesn't
fly - it requires at least two git-ls-tree calls per revision which
would bog things down awfully (to roughly half of the original speed).

No it doesn't. It requires one git-ls-tree WHEN SOMETHING IS RENAMED.

In other words, basically never.

Huh? I don't see that now (and caps don't help me see it better). That's
certainly not what is in [1], and I don't see _how_ to detect the
renames in this case, and what would I be actually doing git-ls-tree for
when I've already detected the rename. Based on [1], I'd be doing
git-ls-tree merely to detect that a file _disappeared_ in the first
place, I have to do other stuff to detect the renames themselves.

Dear diary, on Sun, Mar 26, 2006 at 09:35:02AM CEST, I got a letter
where Ryan Anderson [off-list ref] said that...

quoted

A simple example is the first loop in git-annotate.perl.  (Which was
basically written by Linus, I just translated it from a
shell/pseudo-code example into Perl)

Thanks for the hint. Unfortunately, this is precisely the thing I want
to avoid, that is essentially reimplementing part of git-rev-list - to
do something good, I would have to do my own toposort and merge by date
between parallel lines. OTOH, I might just construct a large revlist
commandline specifying all the segments I'm interested in and see what
happens when I run that.

Besides, doing it in shell would be pretty ugly job (forcing me to
finally rewrite it in perl is not a bad thing but that'd be a somewhat
larger project since I share various common routines with other cg
tools, etc).

If you decide to modify rev-list to do rename tracking you might want
to have a look at how this is done in blame.c. git-blame only tracks
one file (since that is what it needs) but I think it should be
possible to track multiple files with a similar approach.

- Fredrik