# HG changeset patch
# User Phil Cohen <phillco@fb.com>
# Date 2017-12-27 19:53:21
# Node ID 87918218da70cac7ec380335aa6ff1334c10b518
# Parent  b55a142f00c5a92a19ff94fbe9b5d09e28716860

merge: raise before running mergedriver if using IMM

Merge driver scripts run in the working copy, so disable with IMM for now.

Differential Revision: https://phab.mercurial-scm.org/D1781

diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -1556,6 +1556,9 @@ def applyupdates(repo, actions, wctx, mc
     usemergedriver = not overwrite and mergeactions and ms.mergedriver
 
     if usemergedriver:
+        if wctx.isinmemory():
+            raise error.InMemoryMergeConflictsError("in-memory merge does not "
+                                                    "support mergedriver")
         ms.commit()
         proceed = driverpreprocess(repo, ms, wctx, labels=labels)
         # the driver might leave some files unresolved