Add mq patch names to tagscache instead of overriding lookup.

This makes mq patch names visible in hg log and hg tags. It also
resolves the names only once, rather than on every lookup.

hgext/mq.py

@@ -1280,28 +1280,30 b' def version(ui, q=None):'
 
 def reposetup(ui, repo):
     repomap[repo] = queue(ui, repo.join(""))
-    oldlookup = repo.lookup
+    oldtags = repo.tags
+
+    def qtags():
+        if repo.tagscache:
+            return repo.tagscache
 
-    def qlookup(key):
-        try:
-            return oldlookup(key)
-        except hg.RepoError:
-            q = repomap[repo]
+        tagscache = oldtags()
+
+        q = repomap[repo]
+        if len(q.applied) == 0:
+            return tagscache
 
-            qpatchnames = { 'qtip': -1, 'qbase': 0 }
-            if key in qpatchnames:
-                if len(q.applied) == 0:
-                    self.ui.warn('No patches applied\n')
-                    raise
-                patch = q.applied[qpatchnames[key]].split(':')[0]
-                return revlog.bin(patch)
+        mqtags = [patch.split(':') for patch in q.applied]
+        mqtags.append((mqtags[-1][0], 'qtip'))
+        mqtags.append((mqtags[0][0], 'qbase'))
+        for patch in mqtags:
+            if patch[1] in tagscache:
+                repo.ui.warn('Tag %s overrides mq patch of the same name\n' % patch[1])
+            else:
+                tagscache[patch[1]] = revlog.bin(patch[0])
 
-            patch = q.isapplied(key)
-            if not patch:
-                raise
-            return revlog.bin(patch[1])
+        return tagscache
 
-    repo.lookup = qlookup
+    repo.tags = qtags
 
 cmdtable = {
     "qapplied": (applied, [], 'hg qapplied [PATCH]'),