chgserver: use global ui instead of repo ui for dispatch.request.ui

chgserver: use global ui instead of repo ui for dispatch.request.ui

Before this patch, chgserver will use repo ui as dispatch.request.ui, while
req.ui is designed to be global ui without repo config.

Passing repo ui as dispatch.request.ui leads to repo.ui being incorrect, which
can lead to unwanted results. For example, if the repo config has [extensions],
it could affect which localrepository.featuresetupfuncs get executed and the
repo may have an incorrect list of supported requirements.

This patch changes _renewui to return both global ui and repo ui. The global
ui is passed to req.ui, and the repo ui is used to calculate confighash. It
will make chg pass test-largefiles-misc.t and test-requires.t, which are both
related to repo requirements.

--- a/hgext/chgserver.py	Thu Mar 17 18:34:32 2016 +0000
+++ b/hgext/chgserver.py	Thu Mar 17 18:32:10 2016 +0000
@@ -267,7 +267,7 @@
 
     return chgui(srcui)
 
-def _renewui(srcui, args=None):
+def _loadnewui(srcui, args=None):
     if not args:
         args = []
 
@@ -277,14 +277,7 @@
     if util.safehasattr(srcui, '_csystem'):
         newui._csystem = srcui._csystem
 
-    # load wd and repo config, copied from dispatch.py
-    cwds = dispatch._earlygetopt(['--cwd'], args)
-    cwd = cwds and os.path.realpath(cwds[-1]) or None
-    rpath = dispatch._earlygetopt(["-R", "--repository", "--repo"], args)
-    path, newui = dispatch._getlocal(newui, rpath, wd=cwd)
-
     # internal config: extensions.chgserver
-    # copy it. it can only be overrided from command line.
     newui.setconfig('extensions', 'chgserver',
                     srcui.config('extensions', 'chgserver'), '--config')
 
@@ -301,7 +294,15 @@
             # ui.configsource returns 'none' by default
             source = ''
         newui.setconfig(section, name, value, source)
-    return newui
+
+    # load wd and repo config, copied from dispatch.py
+    args = args[:]
+    cwds = dispatch._earlygetopt(['--cwd'], args)
+    cwd = cwds and os.path.realpath(cwds[-1]) or None
+    rpath = dispatch._earlygetopt(["-R", "--repository", "--repo"], args)
+    path, newlui = dispatch._getlocal(newui, rpath, wd=cwd)
+
+    return (newui, newlui)
 
 class channeledsystem(object):
     """Propagate ui.system() request in the following format:
@@ -450,13 +451,13 @@
         """
         args = self._readlist()
         try:
-            self.ui = _renewui(self.ui, args)
+            self.ui, lui = _loadnewui(self.ui, args)
         except error.ParseError as inst:
             dispatch._formatparse(self.ui.warn, inst)
             self.ui.flush()
             self.cresult.write('exit 255')
             return
-        newhash = hashstate.fromui(self.ui, self.hashstate.mtimepaths)
+        newhash = hashstate.fromui(lui, self.hashstate.mtimepaths)
         insts = []
         if newhash.mtimehash != self.hashstate.mtimehash:
             addr = _hashaddress(self.baseaddress, self.hashstate.confighash)
@@ -533,7 +534,7 @@
 
         if set(['HGPLAIN', 'HGPLAINEXCEPT']) & diffkeys:
             # reload config so that ui.plain() takes effect
-            self.ui = _renewui(self.ui)
+            self.ui, _lui = _loadnewui(self.ui)
 
         _clearenvaliases(commands.table)