resourceutil: account for the non-resource-like file hierarchy under py2exe

After 9e367157a990, config files for py2exe were expected to be in
C:\Program Files\Mercurial\mercurial\defaultrc because of the implied resource
structure of 'mercurial.defaultrc.*.rc', relative to the executable.
Accomodating this would require changes to the WIX and Inno scripts (and perhaps
the script that generates the WIX script), as well as 3rd party bundlers like
TortoiseHg.  But these files aren't read as resources anyway- they fall back to
the filesystem APIs.  (If we really wanted to carry on the charade, the
installer would have to also sprinkle various empty __init__.py files around.)

Instead, this simply prunes the 'mercurial.' portion of the resource name when
run with py2exe.  (PyOxidizer uses the resources API, not the filesystem
fallback, so it is unaffected.)  Since this hack only affects the py2 Windows
installers and is less risky, I think it's reasonable.  We haven't needed to
load any 3rd party resource up to this point, and would have to make packaging
changes anyway to handle that.

Differential Revision: https://phab.mercurial-scm.org/D8058

mercurial/utils/resourceutil.py

@@ -1,85 +1,96 b''
 # resourceutil.py - utility for looking up resources
 #
 #  Copyright 2005 K. Thananchayan <[e-mail]>
 #  Copyright 2005-2007 Matt Mackall <[e-mail]>
 #  Copyright 2006 Vadim Gelfer <[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.
 
 from __future__ import absolute_import
 
 import imp
 import os
 import sys
 
 from .. import pycompat
 
 
 def mainfrozen():
     """return True if we are a frozen executable.
 
     The code supports py2exe (most common, Windows only) and tools/freeze
     (portable, not much used).
     """
     return (
         pycompat.safehasattr(sys, "frozen")
         or pycompat.safehasattr(sys, "importers")  # new py2exe
         or imp.is_frozen("__main__")  # old py2exe
     )  # tools/freeze
 
 
 # the location of data files matching the source code
 if mainfrozen() and getattr(sys, 'frozen', None) != 'macosx_app':
     # executable version (py2exe) doesn't support __file__
     datapath = os.path.dirname(pycompat.sysexecutable)
     _rootpath = datapath
+
+    # The installers store the files outside of library.zip, like
+    # C:\Program Files\Mercurial\defaultrc\*.rc.  This strips the
+    # leading "mercurial." off of the package name, so that these
+    # pseudo resources are found in their directory next to the
+    # executable.
+    def _package_path(package):
+        dirs = package.split(b'.')
+        assert dirs[0] == b'mercurial'
+        return os.path.join(_rootpath, *dirs[1:])
+
 else:
     datapath = os.path.dirname(os.path.dirname(pycompat.fsencode(__file__)))
     _rootpath = os.path.dirname(datapath)
 
+    def _package_path(package):
+        return os.path.join(_rootpath, *package.split(b'.'))
+
 try:
     from importlib import resources
 
     from .. import encoding
 
     # Force loading of the resources module
     resources.open_binary  # pytype: disable=module-attr
 
     def open_resource(package, name):
         return resources.open_binary(  # pytype: disable=module-attr
             pycompat.sysstr(package), pycompat.sysstr(name)
         )
 
     def is_resource(package, name):
         return resources.is_resource(
             pycompat.sysstr(package), encoding.strfromlocal(name)
         )
 
     def contents(package):
         for r in resources.contents(pycompat.sysstr(package)):
             yield encoding.strtolocal(r)
 
 
 except (ImportError, AttributeError):
 
-    def _package_path(package):
-        return os.path.join(_rootpath, *package.split(b'.'))
-
     def open_resource(package, name):
         path = os.path.join(_package_path(package), name)
         return open(path, 'rb')
 
     def is_resource(package, name):
         path = os.path.join(_package_path(package), name)
 
         try:
             return os.path.isfile(pycompat.fsdecode(path))
         except (IOError, OSError):
             return False
 
     def contents(package):
         path = pycompat.fsdecode(_package_path(package))
 
         for p in os.listdir(path):
             yield pycompat.fsencode(p)