import-checker: show stdlib and relative imports separately

Make the output more useful for debugging problems.

contrib/import-checker.py

@@ -139,7 +139,7 b' def verify_stdlib_on_own_line(source):'
     http://bugs.python.org/issue19510.
 
     >>> list(verify_stdlib_on_own_line('import sys, foo'))
-    ['mixed stdlib and relative imports:\\n   foo, sys']
+    ['mixed imports\\n   stdlib:    sys\\n   relative:  foo']
     >>> list(verify_stdlib_on_own_line('import sys, os'))
     []
     >>> list(verify_stdlib_on_own_line('import foo, bar'))
@@ -147,13 +147,13 b' def verify_stdlib_on_own_line(source):'
     """
     for node in ast.walk(ast.parse(source)):
         if isinstance(node, ast.Import):
-            from_stdlib = {}
+            from_stdlib = {False: [], True: []}
             for n in node.names:
-                from_stdlib[n.name] = n.name in stdlib_modules
-            num_std = len([x for x in from_stdlib.values() if x])
-            if num_std not in (len(from_stdlib.values()), 0):
-                yield ('mixed stdlib and relative imports:\n   %s' %
-                       ', '.join(sorted(from_stdlib.iterkeys())))
+                from_stdlib[n.name in stdlib_modules].append(n.name)
+            if from_stdlib[True] and from_stdlib[False]:
+                yield ('mixed imports\n   stdlib:    %s\n   relative:  %s' %
+                       (', '.join(sorted(from_stdlib[True])),
+                        ', '.join(sorted(from_stdlib[False]))))
 
 class CircularImport(Exception):
     pass

tests/test-module-imports.t

@@ -23,16 +23,21 b' hidden by deduplication algorithm in the'
 these may expose other cycles.
 
   $ hg locate 'mercurial/**.py' | xargs python "$import_checker"
-  mercurial/dispatch.py mixed stdlib and relative imports:
-     commands, error, extensions, fancyopts, hg, hook, util
-  mercurial/fileset.py mixed stdlib and relative imports:
-     error, merge, parser, util
-  mercurial/revset.py mixed stdlib and relative imports:
-     discovery, error, hbisect, parser, phases, util
-  mercurial/templater.py mixed stdlib and relative imports:
-     config, error, parser, templatefilters, util
-  mercurial/ui.py mixed stdlib and relative imports:
-     config, error, formatter, scmutil, util
+  mercurial/dispatch.py mixed imports
+     stdlib:    commands
+     relative:  error, extensions, fancyopts, hg, hook, util
+  mercurial/fileset.py mixed imports
+     stdlib:    parser
+     relative:  error, merge, util
+  mercurial/revset.py mixed imports
+     stdlib:    parser
+     relative:  discovery, error, hbisect, phases, util
+  mercurial/templater.py mixed imports
+     stdlib:    parser
+     relative:  config, error, templatefilters, util
+  mercurial/ui.py mixed imports
+     stdlib:    formatter
+     relative:  config, error, scmutil, util
   Import cycle: mercurial.cmdutil -> mercurial.subrepo -> mercurial.cmdutil
   Import cycle: mercurial.repoview -> mercurial.revset -> mercurial.repoview
   Import cycle: mercurial.fileset -> mercurial.merge -> mercurial.subrepo -> mercurial.match -> mercurial.fileset