Re: Not understanding with git wants to copy one file to another

From: Stefan Beller <sbeller@google.com>
Date: Aug 10, 2017, 17:36 UTC
Message-ID: <CAGZ79kbgb2P7KT_b9xuMj1pN1+jsPfH7YSJNDyDB5dY3cwXCQg@mail.gmail.com>
In-Reply-To: <87mv7773tp.fsf@local.lan>

On Thu, Aug 10, 2017 at 10:03 AM, Harry Putnam <reader@newsguy.com> wrote:

Show 26 quoted lines

> I ran into a line in git commit ouput I had not see before
>
>   #copied:     d0/etc/hosts -> misc/old-readerHOSTvcs-files/etc/hosts
>
> So googling I learned that this might happen if git thinks the two
> files are the same.
>
> I was pretty sure they were not the same so checked them>
>
>  <inside git repo>
>
> diff d0/etc/host misc/old-readerHOSTvcs-files/etc/hosts
>
> The output is a bit long but shows them being quite different.
>
> Some 2 dozen or so lines that dramatically differ.
>
> Here are two that are at least kind of similar but would never be seen
> as the same:
>
> < 192.168.1.43      m2.local.lan       m2       # 00-90-F5-A1-F9-E5
>> 192.168.1.43    m2.local.lan        m2         # win 7
>
> Not to mention they are quite different lines as well.
>
> So what is going on and what should I be looking at?

The diff machinery has a threshold for when it assumes a copy/move of a file. (e.g. "A file is assumed copied when at least 55% of lines are equal")

https://git-scm.com/docs/git-diff

See -C and -M option.

git-status seems to use this machinery as well, but does not expose the options?