Re: possible 'git cp'/how does git detect copies

From: Mircea Bardac <dev@mircea.bardac.net>
Date: Jun 27, 2008, 13:16 UTC
Message-ID: <4864E839.7000204@mircea.bardac.net>
In-Reply-To: <8aa486160806270557w20ce622co1099bceec7bc90f9@mail.gmail.com>

Hi,

Santi Béjar wrote:

Show 7 quoted lines

> On Fri, Jun 27, 2008 at 14:40, Mircea Bardac <dev@mircea.bardac.net> wrote:
>> I was looking today at duplicating a file but, I soon realized that there is
>> no 'git cp' command (this was the "deductive approach to git commands",
>> starting from git mv/rm/...). How does "git diff -C" detect copies (-C is
>> used for this, according to the documentation)?
> 
> Did you followed the "See also −−find−copies−harder."?

I knew this from before but for some reason I forgot about it when I tried it now. The documentation for "git diff -C" is a bit misleading. I have originally tested on git 1.5.2.something and the documentation for -C didn't point to --find-copies-harder. I've quickly installed 1.5.6.1 to test the behavior but not the man pages.

Looking over the online docs for 1.5.6.1, it appears that there is now a reference to --find-copies-harder.

Even so, saying just that "Detect copies as well as renames." is not enough, as it assumes that there is no restriction on the detection process.

 From --find-copies-harder
"For performance reasons, by default, -C option finds copies only if the 
original file of the copy was modified in the same changeset." should be 
moved to -C.

Show 9 quoted lines

>> On a very simple test, I couldn't see this working. I just copied one file,
>> added it, committed the change, ran "git diff -C HEAD^!". There is no place
>> saying that it's contents is copied from some other file (both files are in
>> the repository now).
>>
>> "git blame -C new_copied_file" also doesn't show the commits for the
>> original file.
> 
> git blame -C -C new_copied_file

Ah, duplicating the parameter. Looking better over these options I have noticed that --find-copies-harder for "git diff" can also be replaced with an extra -C. A little bit of consistency would help: either "-C -C", either "--find-copies-harder" in both git blame/diff. Removing from the documentation the deprecated version but keeping the implementation for backwards compatibility might be a solution.

Many thanks, Mircea

P.S. I know that patches are encouraged and technically it's pretty simple to create a documentation patch, but I have not yet formed myself a workflow for sending patches via Git to a maillist (this is a pending task for me)

-- http://mircea.bardac.net