extensions: also search for extension in the 'hgext3rd' package Mercurial extensions are not meant to be normal python package/module. Yet the lack of an official location to install them means that a lot of them actually install as root level python package, polluting the global Python package namespace and risking collision with more legit packages. As we recently discovered, core python actually support namespace package. A way for multiples distinct "distribution" to share a common top level package without fear of installation headache. (Namespace package allow submodule installed in different location (of the 'sys.path') to be imported properly. So we are fine as long as extension includes a proper 'hgext3rd.__init__.py' to declare the namespace package.) Therefore we introduce a 'hgext3rd' namespace packages and search for extension in it. We'll then recommend third extensions to install themselves in it. Strictly speaking we could just get third party extensions to install in 'hgext' as it is also a namespace package. However, this would make the integration of formerly third party extensions in the main distribution more complicated as the third party install would overwrite the file from the main install. Moreover, having an explicit split between third party and core extensions seems like a good idea. The name 'hgext3rd' have been picked because it is short and seems explicit enough. Other alternative I could think of where: - hgextcontrib - hgextother - hgextunofficial

--- a/setup.py	Sun Mar 13 05:17:06 2016 +0900
+++ b/setup.py	Fri Mar 11 10:30:08 2016 +0000
@@ -506,7 +506,7 @@
 packages = ['mercurial', 'mercurial.hgweb', 'mercurial.httpclient',
             'mercurial.pure',
             'hgext', 'hgext.convert', 'hgext.highlight', 'hgext.zeroconf',
-            'hgext.largefiles']
+            'hgext.largefiles', 'hgext3rd']
 
 common_depends = ['mercurial/util.h']