Re: [BUG] diff algorithm selection issue

From: Junio C Hamano <gitster@pobox.com>
Date: May 26, 2020, 16:23 UTC
Message-ID: <xmqqd06qoec9.fsf@gitster.c.googlers.com>
In-Reply-To: <xmqqh7w2oexd.fsf@gitster.c.googlers.com>

Junio C Hamano <gitster@pobox.com> writes:

> the issue, but anyway, somebody seems to be OR'ing in diff_algorithm
> to xdl_opts field after we see --diff-algorithm=minimal and replaced
> XDF_DIFF_ALGORITHM_MASK bits in xdl_opts field in this function, ...

Well, I am not so sure about that diagnosis, actually. I should probably have taken a bit of caffeine before writing my e-mails.

There is no patch needed. --- I simply had misread your report.

> When the config has diff.algorithm=patience set, "git diff --minimal" seems to
> be ignored, and does not give the same output as "git diff --diff-algorithm=minimal",
> but really the same as "git diff --diff-algorithm=patience".

As I wrote, that is absolutely the intended behaviour.

When patience and other algorithm learns how to trade cycles off with output size, --minimal may make a difference, but unlike "--diff-algorithm=minimal" that forces Myers algorithm, the "--minimal" option should not change the underlying algorithm.

Thanks.