Index: hgext/rebase.py
===================================================================
--- hgext/rebase.py
+++ hgext/rebase.py
@@ -17,6 +17,7 @@
 from __future__ import absolute_import
 
 import errno
+import itertools
 import os
 
 from mercurial.i18n import _
@@ -907,6 +908,20 @@
             why_not_imm=whynotimm)
         return True
 
+    # Check for paths in the rebaseset that are likely to later trigger
+    # conflicts or a mergedriver run (and thus cause the whole rebase to later
+    # be restarted).
+    badpaths = ui.configlist("rebase", "experimental.inmemory_disallowed_paths")
+    if badpaths:
+        rebasepaths = set(itertools.chain(*[repo[rev].files() for rev
+            in rebaseset]))
+        intersection = set(badpaths).intersection(rebasepaths)
+        if intersection:
+            whynotimm = "paths matched inmemory_disallowed_paths"
+            ui.log("rebase", "disabling IMM because: %s" % whynotimm,
+                why_not_imm=whynotimm)
+            return True
+
     return False # no change
 
 def _definedestmap(ui, repo, rbsrt, destf=None, srcf=None, basef=None,