--- a/hgext/inhibit.py	Fri Mar 06 21:25:44 2015 -0800
+++ b/hgext/inhibit.py	Sat Mar 07 02:32:43 2015 -0800
@@ -51,6 +51,14 @@
     tr.addfilegenerator('obsinhibit', ('obsinhibit',), writer)
     tr.hookargs['obs_inbihited'] = '1'
 
+def _filterpublic(repo, nodes):
+    """filter out inhibitor on public changeset
+
+    Public changesets are already immune to obsolescence"""
+    getrev = repo.changelog.nodemap.get
+    getphase = repo._phasecache.phase
+    return (n for n in repo._obsinhibit if getphase(repo, getrev(n)))
+
 def _inhibitmarkers(repo, nodes):
     """add marker inhibitor for all obsolete revision under <nodes>
 
@@ -62,7 +70,7 @@
         tr = repo.transaction('obsinhibit')
         try:
             repo._obsinhibit.update(c.node() for c in newinhibit)
-            _schedulewrite(tr, repo._obsinhibit)
+            _schedulewrite(tr, _filterpublic(repo, repo._obsinhibit))
             repo.invalidatevolatilesets()
             tr.close()
         finally:
@@ -79,7 +87,7 @@
         tr = repo.transaction('obsinhibit')
         try:
             repo._obsinhibit -= deinhibited
-            _schedulewrite(tr, repo._obsinhibit)
+            _schedulewrite(tr, _filterpublic(repo, repo._obsinhibit))
             repo.invalidatevolatilesets()
             tr.close()
         finally:

--- a/tests/test-inhibit.t	Fri Mar 06 21:25:44 2015 -0800
+++ b/tests/test-inhibit.t	Sat Mar 07 02:32:43 2015 -0800
@@ -127,3 +127,49 @@
   branch: default
   commit: (clean)
   update: 1 new changesets, 2 branch heads (merge)
+
+check public revision got cleared
+(when adding the second inhibitor, the first one is removed because it is public)
+
+  $ wc -m .hg/store/obsinhibit
+  20 .hg/store/obsinhibit
+  $ hg prune 7
+  1 changesets pruned
+  $ hg debugobsinhibit --hidden 18214586bf78
+  $ wc -m .hg/store/obsinhibit
+  20 .hg/store/obsinhibit
+  $ hg log -G
+  @  9:55c73a90e4b4 add cJ
+  |
+  | o  7:18214586bf78 add cJ
+  |/
+  o  6:cf5c4f4554ce add cH
+  |
+  o  5:5419eb264a33 add cG
+  |
+  o  4:98065434e5c6 add cE
+  |
+  o  0:54ccbc537fc2 add cA
+  
+  $ hg phase --public 7
+  $ hg prune 9
+  1 changesets pruned
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  working directory now at cf5c4f4554ce
+  $ hg debugobsinhibit --hidden 55c73a90e4b4
+  $ wc -m .hg/store/obsinhibit
+  20 .hg/store/obsinhibit
+  $ hg log -G
+  o  9:55c73a90e4b4 add cJ
+  |
+  | o  7:18214586bf78 add cJ
+  |/
+  @  6:cf5c4f4554ce add cH
+  |
+  o  5:5419eb264a33 add cG
+  |
+  o  4:98065434e5c6 add cE
+  |
+  o  0:54ccbc537fc2 add cA
+  
+