Re: [PATCH] grep --no-index: allow use of "git grep" outside a git repository

Jeff King [off-list ref] writes:

Agreed. That is the most common log grep pattern for me (author + grep),
and I always want all-match. I see from later in the thread, though,
that implementing it is not as straightforward as we might hope.

I haven't looked at the codepath for quite some time but I have a feeling
that it probably won't be too bad.

It just won't be as simple as flipping the all_match bit with a one-liner.

Before calling compile_grep_patterns() in revision.c::setup_revisions(),
we probably would want to massage revs->grep_filter to result in the
desired grep expression parse tree, i.e. from

    GREP_PATTERN_HEAD("^author .*davvid")
    GREP_PATTERN_HEAD("^committer .*gitster")
    GREP_PATTERN_BODY("difftool")
    GREP_PATTERN_BODY("mergetool")

to

    GREP_PATTERN_HEAD("^author .*davvid")
    GREP_PATTERN_HEAD("^committer .*gitster")
    GREP_NODE_OR(
        GREP_PATTERN_BODY("difftool")
        GREP_PATTERN_BODY("mergetool")
    )