Re: Adding Git to Better SCM Initiative : Comparison

Matthieu Moy [off-list ref] wrote:

linux@horizon.com writes:

quoted

"Rename support" is a kludge to make a fundamentally broken model
less painful.

It's not.

Git _has_ rename support. Look into the code, you'll find some code
whose purpose is to manage renames. And _no_, rename support is not
just a direct consequence of commits being atomic.

Atomic commit help, but if you do nothing else, moving a file and then
trying to merge will fail for example. So, in addition to atomic
commits, you have at least 3 options : explicit file ID (bzr),
recording renames (hg), or detecting renames after-the-fact (git).

Please forgive me for not mentioning that part.  Yes, there are
interesting things to do with renames, and git is doing them, but I
skipped over them because they don't have much to do with the better-scm
definition of the feature:

"Does the system support moving a file or directory to a different
location while still retaining the history of the file?"

You can try to interpret it so it makes sense, but the question is
basically assuming that the history is attached to the file rather than
that the file is attached to the history.

With the latter model, the question is almost silly.  Even with the very
primitive version of git that Linus used to make v2.6.12-rc2 with none
of that fancy code, you can rename a file and git retains the history.
Period.  The qualification "of the file" doesn't even make sense.

As Linus has observed in the past, git does lots of fancy stuff to follow
the history of the code that's *in* the file, but the idea is that a file,
per se, doesn't have a history or even an identity.

You can ask about the history of a file *name*, or of a file's *contents*,
but if not that, what exactly is this "file" thing you want the history of?

Once you've answered that, you can then figure out if the answer to
the question based on whether the file has a history to retain in the
first place.


There are interesting questions about renames that you could ask, but
better-scm isn't asking questions like "can you resolve merges properly
after renaming a file on one branch?"  Maybe I'm being uncharitable, but I
can't help but read the question as asking if the system has a workaround
for a well-known CVS problem.  And one honest answer is "no, there's no
workaround; git doesn't suffer from the problem in the first place."