Re: [PATCH v2 1/3] range-diff/format-patch: refactor check for commit range

[Junio C Hamano <gitster@pobox.com>]

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> Currently, when called with exactly two arguments, `git range-diff`
> tests for a literal `..` in each of the two. Likewise, the argument
> provided via `--range-diff` to `git format-patch` is checked in the same
> manner.
>
> However, `<commit>^!` is a perfectly valid commit range, equivalent to
> `<commit>^..<commit>` according to the `SPECIFYING RANGES` section of
> gitrevisions[7].
>
> In preparation for allowing more sophisticated ways to specify commit
> ranges, let's refactor the check into its own function.

I think the sharing between the two makes sense, but the helper
function should make it clear in its name that this is "the kind of
commit range range-diff wants to take".  Among the commit range "git
log" and friends can take, range-diff can take only a subset of it,
and only a subset of it is meaningful to range-diff (e.g. HEAD^@ is
still a commit range you can give to "git log", but it would not
make much sense to give it to range-diff).

Perhaps

    s/specifies_commit_range/is_range_diff_range/

or something.

> diff --git a/revision.h b/revision.h

Move this to range-diff.h, not revision.h which is about true commit
ranges.

> index 086ff10280d..66777c8e60f 100644
> --- a/revision.h
> +++ b/revision.h
> @@ -457,4 +457,11 @@ int rewrite_parents(struct rev_info *revs,
>   */
>  struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit);
>  
> +/*
> + * Determine whether the given argument defines a commit range, e.g. A..B.
> + * Note that this only validates the format but does _not_ parse it, i.e.
> + * it does _not_ look up the specified commits in the local repository.
> + */

And s/defines a commit range/is usable as a range to range-diff/

Thanks.

> +int specifies_commit_range(const char *range);
> +
>  #endif