hgweb: fix a crash when using web.archivesubrepos

A matcher is required when enabling the subrepo option on archival.archive(),
because that calls match.narrowmatcher(), which accesses fields on the object.
It's therefore probably a bad idea to default the matcher to None on archive(),
but that's a fix for default.

mercurial/hgweb/webcommands.py

@@ -901,7 +901,7 b' def archive(web, req, tmpl):'
 
     ctx = webutil.changectx(web.repo, req)
     pats = []
-    matchfn = None
+    matchfn = scmutil.match(ctx, [])
     file = req.form.get('file', None)
     if file:
         pats = ['path:' + file[0]]

tests/test-archive.t

@@ -20,6 +20,7 b''
   $ hg ci -m "add subrepo"
   $ echo "[web]" >> .hg/hgrc
   $ echo "name = test-archive" >> .hg/hgrc
+  $ echo "archivesubrepos = True" >> .hg/hgrc
   $ cp .hg/hgrc .hg/hgrc-base
   > test_archtype() {
   >     echo "allow_archive = $1" >> .hg/hgrc
@@ -95,6 +96,7 b' invalid arch type should give 404'
   test-archive-1701ef1f1510/bar
   test-archive-1701ef1f1510/baz/bletch
   test-archive-1701ef1f1510/foo
+  test-archive-1701ef1f1510/subrepo/sub
   $ python getarchive.py "$TIP" bz2 | bunzip2 | tar tf - 2>/dev/null
   test-archive-1701ef1f1510/.hg_archival.txt
   test-archive-1701ef1f1510/.hgsub
@@ -102,6 +104,7 b' invalid arch type should give 404'
   test-archive-1701ef1f1510/bar
   test-archive-1701ef1f1510/baz/bletch
   test-archive-1701ef1f1510/foo
+  test-archive-1701ef1f1510/subrepo/sub
   $ python getarchive.py "$TIP" zip > archive.zip
   $ unzip -t archive.zip
   Archive:  archive.zip
@@ -111,6 +114,7 b' invalid arch type should give 404'
       testing: test-archive-1701ef1f1510/bar   OK
       testing: test-archive-1701ef1f1510/baz/bletch   OK
       testing: test-archive-1701ef1f1510/foo   OK
+      testing: test-archive-1701ef1f1510/subrepo/sub   OK
   No errors detected in compressed data of archive.zip.
 
 test that we can download single directories and files