filelog: record what's using attributes

filelog: record what's using attributes

filelog and the file storage interface have some attributes that
ideally shouldn't be there. This commit annotates some of those
attributes with their users so we know where to look when it comes
time to removing them.

This exercise exposed a theme: many attributes are used by LFS,
repo upgrade, verify, and special repo types (like bundlerepo). That
points to missing abstractions on file storage to facilitate these
special needs.

Differential Revision: https://phab.mercurial-scm.org/D4661

--- a/mercurial/filelog.py	Tue Sep 18 18:21:47 2018 -0700
+++ b/mercurial/filelog.py	Tue Sep 18 18:56:02 2018 -0700
@@ -22,10 +22,14 @@
         self._revlog = revlog.revlog(opener,
                                      '/'.join(('data', path + '.i')),
                                      censorable=True)
-        # full name of the user visible file, relative to the repository root
+        # Full name of the user visible file, relative to the repository root.
+        # Used by LFS.
         self.filename = path
+        # Used by repo upgrade.
         self.index = self._revlog.index
+        # Used by verify.
         self.version = self._revlog.version
+        # Used by changegroup generation.
         self._generaldelta = self._revlog._generaldelta
 
     def __len__(self):
@@ -55,21 +59,25 @@
     def linkrev(self, rev):
         return self._revlog.linkrev(rev)
 
+    # Used by LFS, verify.
     def flags(self, rev):
         return self._revlog.flags(rev)
 
     def commonancestorsheads(self, node1, node2):
         return self._revlog.commonancestorsheads(node1, node2)
 
+    # Used by dagop.blockdescendants().
     def descendants(self, revs):
         return self._revlog.descendants(revs)
 
+    # Used by hgweb.
     def headrevs(self):
         return self._revlog.headrevs()
 
     def heads(self, start=None, stop=None):
         return self._revlog.heads(start, stop)
 
+    # Used by hgweb, children extension.
     def children(self, node):
         return self._revlog.children(node)
 
@@ -79,9 +87,11 @@
     def iscensored(self, rev):
         return self._revlog.iscensored(rev)
 
+    # Used by verify.
     def rawsize(self, rev):
         return self._revlog.rawsize(rev)
 
+    # Might be unused.
     def checkhash(self, text, node, p1=None, p2=None, rev=None):
         return self._revlog.checkhash(text, node, p1=p1, p2=p2, rev=rev)
 
@@ -117,6 +127,7 @@
     def files(self):
         return self._revlog.files()
 
+    # Used by verify.
     def checksize(self):
         return self._revlog.checksize()
 
@@ -182,6 +193,10 @@
 
         return True
 
+    # TODO these aren't part of the interface and aren't internal methods.
+    # Callers should be fixed to not use them.
+
+    # Used by LFS.
     @property
     def filename(self):
         return self._revlog.filename
@@ -190,8 +205,7 @@
     def filename(self, value):
         self._revlog.filename = value
 
-    # TODO these aren't part of the interface and aren't internal methods.
-    # Callers should be fixed to not use them.
+    # Used by bundlefilelog, unionfilelog.
     @property
     def indexfile(self):
         return self._revlog.indexfile
@@ -200,10 +214,12 @@
     def indexfile(self, value):
         self._revlog.indexfile = value
 
+    # Used by LFS, repo upgrade.
     @property
     def opener(self):
         return self._revlog.opener
 
+    # Used by repo upgrade.
     def clone(self, tr, destrevlog, **kwargs):
         if not isinstance(destrevlog, filelog):
             raise error.ProgrammingError('expected filelog to clone()')