phases: handle errors other than ENOENT appropriately

mercurial/phases.py

@@ -1,39 +1,41 b''
 # Mercurial phases support code
 #
 # Copyright 2011 Pierre-Yves David <[e-mail]>
 #                Logilab SA        <[e-mail]>
 #                Augie Fackler     <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
+import errno
 from node import nullid, bin, hex
 
 allphases = range(2)
 trackedphases = allphases[1:]
 
 def readroots(repo):
     """Read phase roots from disk"""
     roots = [set() for i in allphases]
     roots[0].add(nullid)
     try:
         f = repo.sopener('phaseroots')
         try:
             for line in f:
                 phase, nh = line.strip().split()
                 roots[int(phase)].add(bin(nh))
         finally:
             f.close()
-    except IOError:
-        pass # default value are enough
+    except IOError, inst:
+        if inst.errno != errno.ENOENT:
+            raise
     return roots
 
 def writeroots(repo):
     """Write phase roots from disk"""
     f = repo.sopener('phaseroots', 'w', atomictemp=True)
     try:
         for phase, roots in enumerate(repo._phaseroots):
             for h in roots:
                 f.write('%i %s\n' % (phase, hex(h)))
     finally:
         f.close()