Re: WG: [git-for-windows/git] log -L/<regex>/,+1 not accepted (#1856)

[Jeff King <peff@peff.net>]

On Tue, Oct 02, 2018 at 06:56:29AM +0000, Peter.Dolland@mt.com wrote:

> Please see my original observation below.
> Is it possible, to extend the git-log syntax in the way, that it
> accepts the short -L option (without :file) of blame in unique cases
> (only one file is logged or respectively the -L expression may be
> valid for all logged files)? It would be nice for command line users!

That would be nice, but I suspect in many cases the regex will be less
unique than you might hope. E.g., if you're looking for the log of a
particular function, you care about where it's defined. But unless you
write your regex very carefully, you're going to also match places where
it's called.

I have a hacky script (included below) that uses an already-built ctags
index to pick the correct file.

> Alternatively I could also imagine the extension of the blame
> functionality in the direction to see a whole history instead of only
> the last modification.

Have you tried using a blame interface that supports parent-reblaming
(i.e., once you blame a line to a particular commit, you can restart the
blame from that commit's parent, digging further into history each
time)? I use "tig blame" for this, and I find that I very rarely
actually turn to "log -L".

-Peff

-- >8 --
#!/usr/bin/env perl

if (!@ARGV) {
  print STDERR "usage: git flog [options] <function>\n";
  exit 1;
}

my $func = pop @ARGV;
my $file = get_file_from_tags($func);
my $regex = '[^A-Za-z_]' . $func . '[^A-Za-z0-9_]';
exec qw(git log), "-L:$regex:$file", @ARGV;
exit 1;

sub get_file_from_tags {
  my $token = shift;

  open(my $fh, '<', 'tags')
    or die "unable to open tags: $!\n";
  while (<$fh>) {
    chomp;

    # this isn't exactly right, as the Ex command may contain
    # embedded tabs, but it's accurate for the token and filename,
    # which come before, and probably good enough to match extension fields
    # which come after
    my @fields = split /\t/;

    next unless $fields[0] eq $token;

    # only look for functions; assumes your ctags uses the "kind"
    # extension field. Note also that some implementations write the "kind:"
    # header and some do not. This handles both.
    next unless grep { /^(kind:\s*)?f$/ } @fields;

    # there may be more, but we don't have any way of disambiguating,
    # so just return the first match
    return $fields[1];
  }

  die "unknown token: $token\n";
}