Re: [PATCH] Add the --submodule-summary option to the diff option family

Johannes Schindelin [off-list ref] writes:

quoted

quoted

+		if (prepare_revision_walk(&rev))
+			message = "(revision walker failed)";

If prepare_revision_walk() failed for whatever reason, can we trust
fast_forward/fast_backward at this point?

No, but it is not used in that case, either, because message is not NULL 
anymore.

It is used in that case a few lines below to decide if you add the third
dot.  That's why I asked.

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+	}
+
+	strbuf_addf(&sb, "Submodule %s %s..", path,
+			find_unique_abbrev(one, DEFAULT_ABBREV));
+	if (!fast_backward && !fast_forward)
+		strbuf_addch(&sb, '.');

Our output methods translate ANSI, so the strbufs only hold the ANSI 
sequences.

I'll always trust two Johannes's on Windows matters ;-)

I have no idea why "submodule --summary" uses --first-parent, but 
personally, I would _hate_ it not to see the merged commits in the diff.

For a summary, you might get away with seeing

	> Merge bla
	> Merge blub
	> Merge this
	> Merge that

but in a diff that does not cut it at all.

As long as bla/blub/this/that are descriptive enough, I do not see at all
why you think "summary" is Ok and "diff" is not.  If your response were
"it is just a matter of taste; to some people (or project) --first-parent
is useful and for others it is not", I would understand it, and it would
make sense to use (or not use) --first-parent consistently between this
codepath and "submodule --summary", though.

In any case, just to safe-guard against sick minds, I can add a check that 
says that left, right, and all the merge bases _cannot_ have any flags 
set, otherwise we output "(you should visit a psychiatrist)" or some such.

I wouldn't suggest adding such a kludge.  Being insulting to the user when
we hit a corner case _we_ cannot handle does not help anybody, does it?

I see two saner options.  Doing this list walking in a subprocess so that
you wouldn't have to worry about object flags at all in this case would
certainly be easier; the other option obviously is to have a separate
object pool ala libgit2, but that would be a much larger change.