--- a/mercurial/hgweb/webutil.py	Thu Dec 14 22:07:46 2017 +0900
+++ b/mercurial/hgweb/webutil.py	Sun Dec 17 18:28:15 2017 +0900
@@ -545,7 +545,8 @@
 def diffstatgen(ctx, basectx):
     '''Generator function that provides the diffstat data.'''
 
-    stats = patch.diffstatdata(util.iterlines(ctx.diff(basectx)))
+    stats = patch.diffstatdata(
+        util.iterlines(ctx.diff(basectx, noprefix=False)))
     maxname, maxtotal, addtotal, removetotal, binary = patch.diffstatsum(stats)
     while True:
         yield stats, maxname, maxtotal, addtotal, removetotal, binary

--- a/tests/test-hgweb-diffs.t	Thu Dec 14 22:07:46 2017 +0900
+++ b/tests/test-hgweb-diffs.t	Sun Dec 17 18:28:15 2017 +0900
@@ -306,6 +306,23 @@
   </html>
   
 
+set up hgweb with git diffs + noprefix
+
+  $ killdaemons.py
+  $ hg serve --config 'diff.git=1' --config 'diff.noprefix=1' -p $HGPORT -d \
+  > --pid-file=hg.pid -A access.log -E errors.log
+  $ cat hg.pid >> $DAEMON_PIDS
+
+patch header and diffstat
+
+  $ get-with-headers.py localhost:$HGPORT 'rev/0' \
+  > | egrep 'files changed|---|\+\+\+'
+       2 files changed, 2 insertions(+), 0 deletions(-)
+  <span id="l1.2" class="minusline">--- /dev/null</span><a href="#l1.2"></a>
+  <span id="l1.3" class="plusline">+++ a</span><a href="#l1.3"></a>
+  <span id="l2.2" class="minusline">--- /dev/null</span><a href="#l2.2"></a>
+  <span id="l2.3" class="plusline">+++ b</span><a href="#l2.3"></a>
+
 set up hgweb with git diffs
 
   $ killdaemons.py