import-checker: check modules for pure Python build correctly

import-checker: check modules for pure Python build correctly

Before this patch, "import-checker.py" just replaces "/" in specified
filenames by ".". This makes modules for pure Python build belong to
"mercurial.pure" package, and prevents "import-checker.py" from
correctly checking about cyclic dependency in them.

This patch discards "pure" component from fully qualified name of such
modules.

To avoid discarding "pure" from the module name of standard libraries
unexpectedly, this patch allows "dotted_name_of_path" to discard
"pure" only from Mercurial specific modules, which are specified via
command line arguments.

--- a/contrib/import-checker.py	Fri Oct 17 02:07:05 2014 +0900
+++ b/contrib/import-checker.py	Fri Oct 17 02:07:05 2014 +0900
@@ -8,11 +8,13 @@
 import BaseHTTPServer
 import zlib
 
-def dotted_name_of_path(path):
+def dotted_name_of_path(path, trimpure=False):
     """Given a relative path to a source file, return its dotted module name.
 
     >>> dotted_name_of_path('mercurial/error.py')
     'mercurial.error'
+    >>> dotted_name_of_path('mercurial/pure/parsers.py', trimpure=True)
+    'mercurial.parsers'
     >>> dotted_name_of_path('zlibmodule.so')
     'zlib'
     """
@@ -20,6 +22,8 @@
     parts[-1] = parts[-1].split('.', 1)[0] # remove .py and .so and .ARCH.so
     if parts[-1].endswith('module'):
         parts[-1] = parts[-1][:-6]
+    if trimpure:
+        return '.'.join(p for p in parts if p != 'pure')
     return '.'.join(parts)
 
 
@@ -220,7 +224,7 @@
     any_errors = False
     for source_path in argv[1:]:
         f = open(source_path)
-        modname = dotted_name_of_path(source_path)
+        modname = dotted_name_of_path(source_path, trimpure=True)
         src = f.read()
         used_imports[modname] = sorted(
             imported_modules(src, ignore_nested=True))