# HG changeset patch
# User Phil Cohen <phillco@fb.com>
# Date 1515130623 28800
# Node ID 9a50ffd15b252eb50e0343c5560ec3388c4eef84
# Parent  c0439e11af16f9b79a4649ca5d572b26917a89e3
filemerge: only write in-memory backup during premerge

This wasn't broken, but should mirror the non-in memory case to save an extra
write.

Differential Revision: https://phab.mercurial-scm.org/D1807

diff -r c0439e11af16 -r 9a50ffd15b25 mercurial/filemerge.py
--- a/mercurial/filemerge.py	Thu Jan 04 21:36:58 2018 -0800
+++ b/mercurial/filemerge.py	Thu Jan 04 21:37:03 2018 -0800
@@ -636,7 +636,8 @@
         # merging in-memory, we must redirect the backup to the memory context
         # so we don't disturb the working directory.
         relpath = back[len(repo.wvfs.base) + 1:]
-        wctx[relpath].write(fcd.data(), fcd.flags())
+        if premerge:
+            wctx[relpath].write(fcd.data(), fcd.flags())
         return wctx[relpath]
     else:
         if premerge: