interhg: use uisetup() instead of module-load side effects

This fixes an infinite recursion bug caused by visiting a bad subpage
of the help handler repeatedly, which caused the wrapper for the
templater's escape filter to get installed twice and resulted in
infinite recursion.

hgext/interhg.py

@@ -1,80 +1,81 b''
 # interhg.py - interhg
 #
 # Copyright 2007 OHASHI Hideya <[e-mail]>
 #
 # Contributor(s):
 #   Edward Lee <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''expand expressions into changelog and summaries
 
 This extension allows the use of a special syntax in summaries, which
 will be automatically expanded into links or any other arbitrary
 expression, much like InterWiki does.
 
 A few example patterns (link to bug tracking, etc.) that may be used
 in your hgrc::
 
   [interhg]
   issues = s!issue(\\d+)!<a href="http://bts/issue\\1">issue\\1</a>!
   bugzilla = s!((?:bug|b=|(?=#?\\d{4,}))(?:\\s*#?)(\\d+))!<a..=\\2">\\1</a>!i
   boldify = s!(^|\\s)#(\\d+)\\b! <b>#\\2</b>!
 '''
 
 import re
 from mercurial.hgweb import hgweb_mod
 from mercurial import templatefilters, extensions
 from mercurial.i18n import _
 
-orig_escape = templatefilters.filters["escape"]
-
 interhg_table = []
 
-def interhg_escape(x):
-    escstr = orig_escape(x)
-    for regexp, format in interhg_table:
-        escstr = regexp.sub(format, escstr)
-    return escstr
+def uisetup(ui):
+    orig_escape = templatefilters.filters["escape"]
 
-templatefilters.filters["escape"] = interhg_escape
+    def interhg_escape(x):
+        escstr = orig_escape(x)
+        for regexp, format in interhg_table:
+            escstr = regexp.sub(format, escstr)
+        return escstr
+
+    templatefilters.filters["escape"] = interhg_escape
 
 def interhg_refresh(orig, self, *args, **kwargs):
     interhg_table[:] = []
     for key, pattern in self.repo.ui.configitems('interhg'):
         # grab the delimiter from the character after the "s"
         unesc = pattern[1]
         delim = re.escape(unesc)
 
         # identify portions of the pattern, taking care to avoid escaped
         # delimiters. the replace format and flags are optional, but delimiters
         # are required.
         match = re.match(r'^s%s(.+)(?:(?<=\\\\)|(?<!\\))%s(.*)%s([ilmsux])*$'
                          % (delim, delim, delim), pattern)
         if not match:
             self.repo.ui.warn(_("interhg: invalid pattern for %s: %s\n")
                               % (key, pattern))
             continue
 
         # we need to unescape the delimiter for regexp and format
         delim_re = re.compile(r'(?<!\\)\\%s' % delim)
         regexp = delim_re.sub(unesc, match.group(1))
         format = delim_re.sub(unesc, match.group(2))
 
         # the pattern allows for 6 regexp flags, so set them if necessary
         flagin = match.group(3)
         flags = 0
         if flagin:
             for flag in flagin.upper():
                 flags |= re.__dict__[flag]
 
         try:
             regexp = re.compile(regexp, flags)
             interhg_table.append((regexp, format))
         except re.error:
             self.repo.ui.warn(_("interhg: invalid regexp for %s: %s\n")
                               % (key, regexp))
     return orig(self, *args, **kwargs)
 
 extensions.wrapfunction(hgweb_mod.hgweb, 'refresh', interhg_refresh)