Re: diff alias which used to work in version 2.27, failing from version 2.28 onwards

[Mikael Magnusson <mikachu@gmail.com>]

On 8/24/23, Reverdell  Auriane <auriane.reverdell@cscs.ch> wrote:
> Hi,
>
> To output the diff of a specific commit, I created the alias dici (see
> below), git dici 12345 or git dici to output the diff of the HEAD:
>
> [alias]
>     dici = !git diff ${1:-HEAD}^..${1:-HEAD}
>
> a trace for this alias gives (same trace for both git 2.27 and 2.28!):
>
> 14:38:45.275964 git.c:439               trace: built-in: git diff
> a2028e7b^..a2028e7b a2028e7b
>
> The commit number is put again at the end of the command (the wanted alias
> is supposed to output only `git diff a2028e7b^..a2028e7b`), this was
> accepted by version 2.27 but not by the version 2.28. For now, my temporary
> fix is adding a bash comment at the end of the alias:
>
> [alias]
>     dici = "!git diff ${1:-HEAD}^..${1:-HEAD} #"
>
> Note: the first alias still doesn't work with the latest git versions
> (tested with 2.40.0, 2.39.2, 2.37.5).
>
> Is that expected behavior? if yes, how is the right/clean way to discard the
> command line argument of the alias?

If you want to interpolate arguments in the command string, the safest
way is something like
dici = !sh -c 'git diff ${1:-HEAD}~..${1:-HEAD}' sh

(but why not just use git show?)

you can also use the ^! syntax instead:
dici = !sh -c 'git diff ${1:-HEAD}^!' sh

-- 
Mikael Magnusson