keyword: restore kwtemplater.match at the end of wrapped webcommands

Before this patch, kwweb_skip doesn't restore kwtemplater.match after
wrapped webcommands. This suppresses keyword expansion at wrapped
webcommands.

Typical usecase of this issue is "file" webcommand after annotate,
changeset, filediff or so on.

To ensure kwtemplater.match=util.never while original webcommand
running, this patch makes kwweb_skip yield values returned by it,
because it returns generator object.

hgext/keyword.py

@@ -675,8 +675,13 b' def reposetup(ui, repo):'
 
     def kwweb_skip(orig, web, req, tmpl):
         '''Wraps webcommands.x turning off keyword expansion.'''
+        origmatch = kwt.match
         kwt.match = util.never
-        return orig(web, req, tmpl)
+        try:
+            for chunk in orig(web, req, tmpl):
+                yield chunk
+        finally:
+            kwt.match = origmatch
 
     def kw_amend(orig, ui, repo, commitfunc, old, extra, pats, opts):
         '''Wraps cmdutil.amend expanding keywords after amend.'''

tests/test-keyword.t

@@ -1019,6 +1019,7 b' kwexpand nonexistent'
 hg serve
  - expand with hgweb file
  - no expansion with hgweb annotate/changeset/filediff
+ - expand with hgweb file, again
  - check errors
 
   $ hg serve -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
@@ -1078,6 +1079,18 b' hg serve'
   
   
   
+
+(check "kwweb_skip"-ed webcommand doesn't suppress expanding keywords
+at subsequent webcommands)
+
+  $ get-with-headers.py localhost:$HGPORT 'file/tip/a/?style=raw'
+  200 Script output follows
+  
+  expand $Id: a bb948857c743 Thu, 01 Jan 1970 00:00:02 +0000 user $
+  do not process $Id:
+  xxx $
+  $Xinfo: User Name <[e-mail]>: firstline $
+
   $ cat errors.log
 #endif