[PATCH 5 of 5] graphlog: paths/-I/-X handling requires a new revset

[Matt Mackall]

On Thu, 2012-02-23 at 18:10 +0100, Patrick Mezard wrote:
> # HG changeset patch
> # User Patrick Mezard <patrick at mezard.eu>
> # Date 1330016720 -3600
> # Node ID 5a627b49b4d94a627b6e990f07f7a5544e9376bf
> # Parent  1bfc7ba8b404b650bb360d36bd41c11a80d6f5ab
> graphlog: paths/-I/-X handling requires a new revset
> 
> The filtering logic of match objects cannot be reproduced with the existing
> revsets as it operates at changeset files level. A changeset touching "a" and
> "b" is matched by "-I a -X b" but not by "file(a) and not file(b)".

Interesting.

The basic logic of include/exclude works like this (match.py:74):

            if include:
                if exclude:
                    m = lambda f: im(f) and not em(f) and pm(f)

In English, a file matches if it's included AND not excluded AND matches
the base pattern (which might be "all files").

The next question is: how is this pattern matching applied to the set of
files in a changeset? The log code has this (cmdutil.py:1083):

        # The slow path checks files modified in every changeset.                                                                                                                                 
        for i in sorted(revs):
            ctx = change(i)
            matches = filter(match, ctx.files())
            if matches:
                fncache[i] = matches
                wanted.add(i)

..which considers a changeset matching if ANY individual file matches. Which gives us three cases:

 -I files and -X files have no overlap -> equivalent to just -I (your original example)
 -I files and -X files overlap completely -> empty set
 -I files and -X files overlap partially -> complex!

But I think there's a relatively simple way to add a revset to deal with this:

 everyfile(pattern) -> match changesets where ALL files match pattern

So for a case like:

 hg log -I tests -X **.py

..we get:

 hg log -r 'file(tests) and not everyfile("**.py")'

Cases:

  cset has tests/foo.t -> matches
  cset has tests/foo.t and tests/foo.py -> matches
  cset has test/foo.py -> doesn't match
  cset has tests/foo.t and other/foo.py -> matches

There's probably some way to show this is correct formally with
DeMorgan's rule, but I don't see an obvious notation.

Also note: multiple -I and -X patterns get ORed together, as do base
patterns, so a complex command like this:

 hg log p1 p2 -I i1 -I i2 -X x1 -X x2

becomes

(file(p1) or file(p2)) and (file(i1) or file(i2)) and not (everyfile(x1)
or everyfile(x2))

-- 
Mathematics is the supreme nostalgia of our time.