Re: allow a differn't diff.context config for git format-patch

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 23, 2019, 03:45 UTC
Message-ID: <xmqqftq95qr6.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20190423030648.GA6344@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> ... I don't think it would be
> too big a problem for format-patch to learn some options to configure
> its diffs. We already have some options in format.* for various things.

I am not sure; diff.context is rather special in that the variable behind it belongs to the diff layer and is set via diff_config that is called by diff_ui_config that in turn is called by log_config which is called by format_config.

If we want to say "format.context" trumps "diff.config", then a new internal variable to receive the value of the variable must be invented and after the config gets read, cmd_format_patch() needs to do something silly like this:

                git_config(git_format_config, NULL);
        +	if (format_context != -1)
        +		diff_default_context = format_context;
                repo_init_revisions(the_repository, &rev, prefix);

committing layering violation by exposing diff_default_context variable.