changegroup: drop special-casing of flat manifests

changegroup: drop special-casing of flat manifests

Since c08814b48ae5 (changegroup: avoid iterating the whole manifest,
2015-12-04), the manifest linkrev callback iterates over only the
files that were touched according the the changeset. Before that
change, we iterated over all files returned in
manifest.readfast(). That method returns the files in the delta, if
the delta parent is a parent, otherwise it returns the full
manifest. Most manifest revisions end up using one of the parents as
its delta parent, so most of the time, the method returns a short
manifest. It seems that that happens often enough that it doesn't
really matter; I could not reproduce the timings reported in that
change.

Since the treemanifest code now works quite differently, and since
that code also works correctly for flat manifests, let's drop the
special-casing of flat manifests.

--- a/mercurial/changegroup.py	Fri Feb 12 23:09:09 2016 -0800
+++ b/mercurial/changegroup.py	Mon Feb 22 14:43:14 2016 -0800
@@ -656,8 +656,7 @@
         clrevorder = {}
         mfs = {} # needed manifests
         fnodes = {} # needed file nodes
-        # maps manifest node id -> set(changed files)
-        mfchangedfiles = {}
+        changedfiles = set()
 
         # Callback for the changelog, used to collect changed files and manifest
         # nodes.
@@ -670,7 +669,7 @@
             mfs.setdefault(n, x)
             # Record a complete list of potentially-changed files in
             # this manifest.
-            mfchangedfiles.setdefault(n, set()).update(c[3])
+            changedfiles.update(c[3])
             return x
 
         self._verbosenote(_('uncompressed size of bundle content:\n'))
@@ -703,7 +702,7 @@
             'treemanifest' not in repo.requirements)
 
         for chunk in self.generatemanifests(commonrevs, clrevorder,
-                fastpathlinkrev, mfs, mfchangedfiles, fnodes):
+                fastpathlinkrev, mfs, fnodes):
             yield chunk
         mfs.clear()
         clrevs = set(cl.rev(x) for x in clnodes)
@@ -719,9 +718,6 @@
                 revs = ((r, llr(r)) for r in filerevlog)
                 return dict((fln(r), cln(lr)) for r, lr in revs if lr in clrevs)
 
-        changedfiles = set()
-        for x in mfchangedfiles.itervalues():
-            changedfiles.update(x)
         for chunk in self.generatefiles(changedfiles, linknodes, commonrevs,
                                         source):
             yield chunk
@@ -732,7 +728,7 @@
             repo.hook('outgoing', node=hex(clnodes[0]), source=source)
 
     def generatemanifests(self, commonrevs, clrevorder, fastpathlinkrev, mfs,
-                          mfchangedfiles, fnodes):
+                          fnodes):
         repo = self._repo
         dirlog = repo.manifest.dirlog
         tmfnodes = {'': mfs}
@@ -763,28 +759,15 @@
                 """
                 clnode = tmfnodes[dir][x]
                 mdata = dirlog(dir).readshallowfast(x)
-                if 'treemanifest' in repo.requirements:
-                    for p, n, fl in mdata.iterentries():
-                        if fl == 't': # subdirectory manifest
-                            subdir = dir + p + '/'
-                            tmfclnodes = tmfnodes.setdefault(subdir, {})
-                            tmfclnode = tmfclnodes.setdefault(n, clnode)
-                            if clrevorder[clnode] < clrevorder[tmfclnode]:
-                                tmfclnodes[n] = clnode
-                        else:
-                            f = dir + p
-                            fclnodes = fnodes.setdefault(f, {})
-                            fclnode = fclnodes.setdefault(n, clnode)
-                            if clrevorder[clnode] < clrevorder[fclnode]:
-                                fclnodes[n] = clnode
-                else:
-                    for f in mfchangedfiles[x]:
-                        try:
-                            n = mdata[f]
-                        except KeyError:
-                            continue
-                        # record the first changeset introducing this filelog
-                        # version
+                for p, n, fl in mdata.iterentries():
+                    if fl == 't': # subdirectory manifest
+                        subdir = dir + p + '/'
+                        tmfclnodes = tmfnodes.setdefault(subdir, {})
+                        tmfclnode = tmfclnodes.setdefault(n, clnode)
+                        if clrevorder[clnode] < clrevorder[tmfclnode]:
+                            tmfclnodes[n] = clnode
+                    else:
+                        f = dir + p
                         fclnodes = fnodes.setdefault(f, {})
                         fclnode = fclnodes.setdefault(n, clnode)
                         if clrevorder[clnode] < clrevorder[fclnode]: