Avoid extra filelogs entries. Right now, there are some situations in which localrepo.filecommit can create filelog entries even though they're not needed. For example: - permissions for a file have changed; - qrefresh can create a filelog entry identical to its parent (see the added test); - convert-repo creates extra filelog entries in every merge where the first parent has added files (for example, changeset ebebe9577a1a of the kernel repo added extra filelog entries to files in the arch/blackfin directory, even though the merge should only touch the drivers/ata directory). This makes "hg log file" in a converted repo less useful than it could be, since it may mention many merges that don't actually touch that specific file. They all come from the same basic problem: localrepo.commit (through filecommit) creates new filelog entries for all files passed to it (except for some cases during a merge). Patch and test case provided by Benoit. This should fix issue351.

# repo.py - repository base classes for mercurial
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

class RepoError(Exception):
    pass

class repository(object):
    def capable(self, name):
        '''tell whether repo supports named capability.
        return False if not supported.
        if boolean capability, return True.
        if string capability, return string.'''
        name_eq = name + '='
        for cap in self.capabilities:
            if name == cap:
                return True
            if cap.startswith(name_eq):
                return cap[len(name_eq):]
        return False