[PATCH 5 of 9 V4] manifest: add manifestlog.get to obtain subdirectory instances

[Durham Goode]

On 9/21/16 11:56 AM, Martin von Zweigbergk wrote:
> On Tue, Sep 20, 2016 at 4:47 PM, Durham Goode <durham at fb.com> wrote:
>> # HG changeset patch
>> # User Durham Goode <durham at fb.com>
>> # Date 1474399441 25200
>> #      Tue Sep 20 12:24:01 2016 -0700
>> # Node ID 52a206d772021194ab4356aeba2c73650851a624
>> # Parent  8cf5f24c100e58ece712703d0e4bb0746bc3087e
>> manifest: add manifestlog.get to obtain subdirectory instances
>>
>> Previously manifestlog only allowed obtaining root level manifests. Future
>> patches will need direct access to subdirectory manifests as part of changegroup
>> creation, so let's add a get() function that knows how to deal with
>> subdirectories.
>>
>> diff --git a/mercurial/manifest.py b/mercurial/manifest.py
>> --- a/mercurial/manifest.py
>> +++ b/mercurial/manifest.py
>> @@ -1033,20 +1033,34 @@ class manifestlog(object):
>>           """Retrieves the manifest instance for the given node. Throws a KeyError
>>           if not found.
>>           """
>> -        if node in self._mancache:
>> -            cachemf = self._mancache[node]
>> -            # The old manifest may put non-ctx manifests in the cache, so skip
>> -            # those since they don't implement the full api.
>> -            if (isinstance(cachemf, manifestctx) or
>> -                isinstance(cachemf, treemanifestctx)):
>> -                return cachemf
>> +        return self.get('', node)
>>
>> -        if self._treeinmem:
>> -            m = treemanifestctx(self._revlog, '', node)
>> +    def get(self, dir, node):
>> +        """Retrieves the manifest instance for the given node. Throws a KeyError
>> +        if not found.
> nit: Does it really throw KeyError? __getitem__ also doesn't seem to.
Interesting point.  It used to, when manifestctx would read from the 
revlog during the constructor, but since we moved that out, it probably 
doesn't now (but probably should).  I'll make the manifestctx and 
treemanifestctx constructors at least check that the node exists in the 
revlog before returning, and throw KeyError if they don't.