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Re: git diff <commit> doesn't quite work as documented?




2017-09-08 0:31 GMT+08:00 Olaf Klischat <olaf.klischat@xxxxxxxxx>:
> oklischat@oklischat:/tmp$ mkdir gittest
> oklischat@oklischat:/tmp$ cd gittest/
> oklischat@oklischat:/tmp/gittest$ git init
> Initialized empty Git repository in /private/tmp/gittest/.git/
> oklischat@oklischat:/tmp/gittest$ echo foo > foo.txt
> oklischat@oklischat:/tmp/gittest$ git add foo.txt
> oklischat@oklischat:/tmp/gittest$ git commit -m foo
> [master (root-commit) 54d55f2] foo
>  1 file changed, 1 insertion(+)
>  create mode 100644 foo.txt
> oklischat@oklischat:/tmp/gittest$ echo bar > bar.txt
> oklischat@oklischat:/tmp/gittest$ git add bar.txt
> oklischat@oklischat:/tmp/gittest$ git commit -m bar
> [master 83b2e74] bar
>  1 file changed, 1 insertion(+)
>  create mode 100644 bar.txt
> oklischat@oklischat:/tmp/gittest$ git tag bar-added
> oklischat@oklischat:/tmp/gittest$ git rm bar.txt
> rm 'bar.txt'
> oklischat@oklischat:/tmp/gittest$ git commit -m 'rm bar'
> [master 3ca4ff9] rm bar
>  1 file changed, 1 deletion(-)
>  delete mode 100644 bar.txt
> oklischat@oklischat:/tmp/gittest$
> oklischat@oklischat:/tmp/gittest$ git checkout bar-added -- bar.txt
> oklischat@oklischat:/tmp/gittest$ git reset HEAD
> oklischat@oklischat:/tmp/gittest$ git status
> On branch master
> Untracked files:
>   (use "git add <file>..." to include in what will be committed)
>
>         bar.txt
>
> nothing added to commit but untracked files present (use "git add" to track)
> oklischat@oklischat:/tmp/gittest$ git diff bar-added   # would expect this to show no differences
> diff --git a/bar.txt b/bar.txt
> deleted file mode 100644
> index 5716ca5..0000000
> --- a/bar.txt
> +++ /dev/null
> @@ -1 +0,0 @@
> -bar
> oklischat@oklischat:/tmp/gittest$
> oklischat@oklischat:/tmp/gittest$ git diff bar-added  -- bar.txt   # dito
> diff --git a/bar.txt b/bar.txt
> deleted file mode 100644
> index 5716ca5..0000000
> --- a/bar.txt
> +++ /dev/null
> @@ -1 +0,0 @@
> -bar

Michael J Gruber is correct about the working-dir/working-tree things.
A quick example: add a new file with

    $ echo bzz > bzz.txt

then do "git diff bar-added".

The result is the same, because "bzz.txt" is not in the working-tree.

Yubin

> oklischat@oklischat:/tmp/gittest$
>
>
> `git diff --help' says:
>
> git diff [--options] <commit> [--] [<path>...]
>            This form is to view the changes you have in your working tree relative to the named <commit>.
>
> If that were entirely true, the last two commands shouldn't have shown
> any differences, right?
>
> On closer inspection, it seems that what `git diff <commit>' really
> does is take only those paths in the working directory that are also
> in <commit> and compare the resulting tree against <commit>.
>
> We should add some option to that git diff form to make it really do
> what the docs claim it does.
>
> Or am I missing something?