Re: [PATCH v2 1/2] t1092: add tests for `git diff-files`

> (Documentation/CodingGuidelines)
>
>  - Redirection operators should be written with space before, but no
>    space after them.  In other words, write 'echo test >"$file"'
>    instead of 'echo test> $file' or 'echo test > $file'.  Note that
>    even though it is not required by POSIX to double-quote the
>    redirection target in a variable (as shown above), our code does so
>    because some versions of bash issue a warning without the quotes.

> We create a new directory that is outside the cone, with or without
> using the sparse-index feature.  We know we are violating the cone,
> and have to override the safety with the "--sparse" option.  OK.
>
> What output do we expect out of "git add" to match in the two cases?
>
> > +     #file present on-disk without modifications
> > +     test_sparse_match git diff-files &&
> > +     test_sparse_match git diff-files newdirectory/testfile &&
>
> As "diff-files" is about comparing between the index and the working
> tree, the new path should not appear in the output when the sparse
> checkout feature with or without the sparse-index feature is NOT in
> use.  Does the picture get different when we are sparse?  IOW, would
> we notice that we now have newdirectory/testfile that is supposed to
> be missing in the index and show that in the output?

> In a non-sparse repository whose HEAD commit does not have
> 'testfile' (e.g. "git" source tree), I get
>
>     $ git diff-files --find-object=HEAD:testfile
>     error: unable to resolve 'HEAD:testfile'
>
> without sparse checkout or sparse index.  It is unclear what value
> we get out of having this test here.