diff mercurial/obsolete.py @ 17831:70b08df24fef

obsolete: add a flag that allows fixing "bumped" changeset

The first obsolescence flag is introduced to allows for fixing the "bumped"
changeset situation.

    bumpedfix == 1.

Creator of new changesets intended to fix "bumped" situation should not forget
to add this flag to the marker. Otherwise the newly created changeset will be
bumped too. See inlined documentation for details.

--- a/mercurial/obsolete.py	Mon Oct 15 14:45:27 2012 +0200
+++ b/mercurial/obsolete.py	Fri Oct 19 00:41:53 2012 +0200
@@ -102,6 +102,37 @@
 _fmfsize = struct.calcsize(_fmfixed)
 _fnodesize = struct.calcsize(_fmnode)
 
+### obsolescence marker flag
+
+## bumpedfix flag
+#
+# When a changeset A' succeed to a changeset A which became public, we call A'
+# "bumped" because it's a successors of a public changesets
+#
+# o    A' (bumped)
+# |`:
+# | o  A
+# |/
+# o    Z
+#
+# The way to solve this situation is to create a new changeset Ad as children
+# of A. This changeset have the same content than A'. So the diff from A to A'
+# is the same than the diff from A to Ad. Ad is marked as a successors of A'
+#
+# o   Ad
+# |`:
+# | x A'
+# |'|
+# o | A
+# |/
+# o Z
+#
+# But by transitivity Ad is also a successors of A. To avoid having Ad marked
+# as bumped too, we add the `bumpedfix` flag to the marker. <A', (Ad,)>.
+# This flag mean that the successors are an interdiff that fix the bumped
+# situation, breaking the transitivity of "bumped" here.
+bumpedfix = 1
+
 def _readmarkers(data):
     """Read and enumerate markers from raw data"""
     off = 0
@@ -351,7 +382,7 @@
     for data in ctx._repo.obsstore.successors.get(ctx.node(), ()):
         yield marker(ctx._repo, data)
 
-def allsuccessors(obsstore, nodes):
+def allsuccessors(obsstore, nodes, ignoreflags=0):
     """Yield node for every successor of <nodes>.
 
     Some successors may be unknown locally.
@@ -363,6 +394,9 @@
         current = remaining.pop()
         yield current
         for mark in obsstore.successors.get(current, ()):
+            # ignore marker flagged with with specified flag
+            if mark[2] & ignoreflags:
+                continue
             for suc in mark[1]:
                 if suc not in seen:
                     seen.add(suc)
@@ -449,7 +483,8 @@
     # get all possible bumped changesets
     tonode = repo.changelog.node
     publicnodes = (tonode(r) for r in repo.revs('public()'))
-    successors = allsuccessors(repo.obsstore, publicnodes)
+    successors = allsuccessors(repo.obsstore, publicnodes,
+                               ignoreflags=bumpedfix)
     # revision public or already obsolete don't count as bumped
     query = '%ld - obsolete() - public()'
     return set(repo.revs(query, _knownrevs(repo, successors)))