--- a/hgext/evolve.py	Fri Jun 19 10:47:02 2015 -0700
+++ b/hgext/evolve.py	Fri Jun 19 11:03:51 2015 -0700
@@ -1950,6 +1950,10 @@
         if not precs:
             raise util.Abort('nothing to prune')
 
+        if not obsolete.isenabled(repo, obsolete.allowunstableopt):
+            if len(repo.revs("(%ld::) - %ld", revs, revs)) != 0:
+                raise util.Abort(_("cannot prune in the middle of a stack"))
+
         # defines successors changesets
         sucs = scmutil.revrange(repo, succs)
         sucs.sort()

--- a/tests/test-evolve.t	Fri Jun 19 10:47:02 2015 -0700
+++ b/tests/test-evolve.t	Fri Jun 19 11:03:51 2015 -0700
@@ -1104,3 +1104,47 @@
   |/
   o  18:0bb66d4c1968@default(draft) a3
   |
+
+Check that prune respects the allowunstable option
+  $ hg up -C .
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg evolve --rev "22::"
+  move:[22] add j2
+  atop:[26] add j1
+  move:[23] add j3
+  atop:[27] add j2
+  working directory is now at 920a35e8dbd0
+  $ glog -r "18::"
+  @  28:920a35e8dbd0@default(draft) add j3
+  |
+  o  27:31e050d895dd@default(draft) add j2
+  |
+  o  26:04b32348803e@default(draft) add j1
+  |
+  | o  20:db3d894869b0@default(draft) add gh
+  | |
+  o |  19:10ffdd7e3cc9@default(draft) add gg
+  |/
+  o  18:0bb66d4c1968@default(draft) a3
+  |
+  $ hg up 19
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ mkcommit c5_
+  created new head
+  $ hg prune '26 + 27'
+  abort: cannot prune in the middle of a stack
+  [255]
+  $ hg prune '19::28'
+  abort: cannot prune in the middle of a stack
+  [255]
+  $ hg prune '26::'
+  3 changesets pruned
+  $ glog -r "18::"
+  @  29:5a6c53544778@default(draft) add c5_
+  |
+  | o  20:db3d894869b0@default(draft) add gh
+  | |
+  o |  19:10ffdd7e3cc9@default(draft) add gg
+  |/
+  o  18:0bb66d4c1968@default(draft) a3
+  |