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 _
@@ -772,6 +773,12 @@
       [rebase]
       experimental.inmemorywarning = Using experimental in-memory rebase
 
+    It will not run if any file paths in the source set match a particular
+    config::
+
+      [rebase]
+      experimental.inmemorydisallowedpaths = Types.php|build.jar
+
     Return Values:
 
     Returns 0 on success, 1 if nothing to rebase or there are
@@ -907,6 +914,21 @@
             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.config("rebase", "experimental.inmemorydisallowedpaths")
+    if badpaths:
+        badpathsre = util.re.compile(badpaths)
+        ctxs = [repo[rev] for rev in rebaseset]
+        paths = set.union(set(ctx.files()) for ctx in ctxs)
+        for path in paths:
+            if badpathsre.match(path):
+                whynotimm = "path matched inmemory_disallowed_paths: %s" % path
+                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,