Re: [PATCH] tests: drop dependency on `git diff` in check-chainlint

> Patrick Steinhardt <ps@pks.im> writes:
> > This strongly reminds me of the thread at [1], where a similar issue was
> > discussed for git-grep(1). Quoting Junio: 
> >
> >> I actually do not think these "we are allowing Git tools to be used
> >> on random garbage" is a good idea to begin with X-<.  If we invented
> >> something nice for our variant in "git grep" and wish we can use it
> >> outside the repository, contributing the feature to implementations
> >> of "grep" would have been the right way to move forward, instead of
> >> contaminating the codebase with things that are not related to Git.
> >
> > So this might not be the best way to go.
> 
> That is not a conclusion I want people to draw.
> 
> Like it or not, "git diff --no-index" will be with us to stay, and
> "--no-index" being "we have abused the rest of Git code to implement
> 'diff' that works _outside_ a Git repository---now go and do your
> thing", we would eventually want to correct it, if it is misbehaving
> when a repository it finds is in a shape it does not like, no?
> 
> We should have what you quoted in mind as a general principle, and
> think twice when we are tempted to hoard useful features for another
> tool we initially wrote for Git and allow them to be used with the
> "--no-index" option, instead of contributing them to the tool that
> does not know or care "git" repositories (like "diff" and "grep").