filelog: declare that filelog implements a storage interface

filelog: declare that filelog implements a storage interface

Now that we have a declared interface, let's declare that filelog
implements it.

Tests have been added that confirm the object conforms to the
interface.

The existing interface checks verify there are no extra public
attributes outside the declared interface. filelog has several
extra attributes. So we added a mechanism to suppress this check.
The goal is to modify the filelog class so we can drop this check.

Differential Revision: https://phab.mercurial-scm.org/D3149

--- a/mercurial/filelog.py	Thu Apr 05 15:09:41 2018 -0700
+++ b/mercurial/filelog.py	Thu Apr 05 15:18:23 2018 -0700
@@ -10,9 +10,13 @@
 import re
 import struct
 
+from .thirdparty.zope import (
+    interface as zi,
+)
 from . import (
     error,
     mdiff,
+    repository,
     revlog,
 )
 
@@ -39,6 +43,7 @@
     m, offs = parsemeta(text)
     return m and "censored" in m
 
[e-mail](repository.ifilestorage)
 class filelog(revlog.revlog):
     def __init__(self, opener, path):
         super(filelog, self).__init__(opener,

--- a/tests/simplestorerepo.py	Thu Apr 05 15:09:41 2018 -0700
+++ b/tests/simplestorerepo.py	Thu Apr 05 15:18:23 2018 -0700
@@ -24,6 +24,9 @@
 from mercurial.thirdparty import (
     cbor,
 )
+from mercurial.thirdparty.zope import (
+    interface as zi,
+)
 from mercurial import (
     ancestor,
     bundlerepo,
@@ -33,6 +36,7 @@
     localrepo,
     mdiff,
     pycompat,
+    repository,
     revlog,
     store,
     verify,
@@ -57,6 +61,7 @@
     if not isinstance(rev, int):
         raise ValueError('expected int')
 
[e-mail](repository.ifilestorage)
 class filestorage(object):
     """Implements storage for a tracked path.
 

--- a/tests/test-check-interfaces.py	Thu Apr 05 15:09:41 2018 -0700
+++ b/tests/test-check-interfaces.py	Thu Apr 05 15:18:23 2018 -0700
@@ -12,6 +12,7 @@
 )
 from mercurial import (
     bundlerepo,
+    filelog,
     httppeer,
     localrepo,
     repository,
@@ -19,13 +20,14 @@
     statichttprepo,
     ui as uimod,
     unionrepo,
+    vfs as vfsmod,
     wireprotoserver,
     wireprototypes,
 )
 
 rootdir = os.path.normpath(os.path.join(os.path.dirname(__file__), '..'))
 
-def checkzobject(o):
+def checkzobject(o, allowextra=False):
     """Verify an object with a zope interface."""
     ifaces = zi.providedBy(o)
     if not ifaces:
@@ -37,6 +39,9 @@
     for iface in ifaces:
         ziverify.verifyObject(iface, o)
 
+    if allowextra:
+        return
+
     # Now verify that the object provides no extra public attributes that
     # aren't declared as part of interfaces.
     allowed = set()
@@ -132,4 +137,10 @@
     httpv2 = wireprotoserver.httpv2protocolhandler(None, None)
     checkzobject(httpv2)
 
+    ziverify.verifyClass(repository.ifilestorage, filelog.filelog)
+
+    vfs = vfsmod.vfs('.')
+    fl = filelog.filelog(vfs, 'dummy.i')
+    checkzobject(fl, allowextra=True)
+
 main()