diff mercurial/phases.py @ 15922:23921c17299a

phases: mechanism to allow extension to alter initial computation of phase

This commit add a whennodata list where extension can register a callback to be
called if no phase related data are found in the repository.

The goal is to ensure the existing extension that move phase data in 2.1 can
compute consistent phase boundary for existing repo.

--- a/mercurial/phases.py	Wed Jan 18 17:11:27 2012 +0100
+++ b/mercurial/phases.py	Wed Jan 18 17:23:54 2012 +0100
@@ -109,7 +109,6 @@
 def readroots(repo):
     """Read phase roots from disk"""
     roots = [set() for i in allphases]
-    roots[0].add(nullid)
     try:
         f = repo.sopener('phaseroots')
         try:
@@ -121,6 +120,8 @@
     except IOError, inst:
         if inst.errno != errno.ENOENT:
             raise
+        for f in repo._phasedefaults:
+            roots = f(repo, roots)
     return roots
 
 def writeroots(repo):