setup.py, make: avoid problems with outdated, existing hgext/__index__.py*

"make clean" already removed __index__.py[cdo], but not the __index__.py
(automatically generated by "python setup.py build_hgextindex").

"setup.py build_hgextindex" did not generate a new index if file
__index__.py[cdo] already existed, because if __index__.py was removed,
the compiled file containing the old information was imported and used.
Generate an empty file (with a new timestamp to generate a new .py[cdo])
instead and make mercurial.extensions ignore the unset docs attribute.

One of the problems was a failed test-help.t, to reproduce:

$ rm hgext/__index__.py*
$ echo 'docs = {"mq": "dummy"}' > hgext/__index__.py
$ make test-help.t

With this a "make clean" or "python setup.py build_hgextindex" helps.

Makefile

@@ -56,7 +56,7 b' clean:'
 	find contrib doc hgext i18n mercurial tests \
 		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
 	rm -f $(addprefix mercurial/,$(notdir $(wildcard mercurial/pure/[a-z]*.py)))
-	rm -f MANIFEST MANIFEST.in mercurial/__version__.py tests/*.err
+	rm -f MANIFEST MANIFEST.in mercurial/__version__.py hgext/__index__.py tests/*.err
 	rm -rf build mercurial/locale
 	$(MAKE) -C doc clean
 

mercurial/extensions.py

@@ -281,7 +281,7 b' def disabled():'
         return dict((name, gettext(desc))
                     for name, desc in __index__.docs.iteritems()
                     if name not in _order)
-    except ImportError:
+    except (ImportError, AttributeError):
         pass
 
     paths = _disabledpaths()
@@ -304,7 +304,7 b' def disabledext(name):'
             return
         else:
             return gettext(__index__.docs.get(name))
-    except ImportError:
+    except (ImportError, AttributeError):
         pass
 
     paths = _disabledpaths()

setup.py

@@ -331,7 +331,9 b' class buildhgextindex(Command):'
 
     def run(self):
         if os.path.exists(self._indexfilename):
-            os.unlink(self._indexfilename)
+            f = open(self._indexfilename, 'w')
+            f.write('# empty\n')
+            f.close()
 
         # here no extension enabled, disabled() lists up everything
         code = ('import pprint; from mercurial import extensions; '