Keep site directories (e.g. site-packages) from being included in

.pth files.  (backport from trunk)

--HG--
branch : setuptools-0.6
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/branches/setuptools-0.6%4066609

EasyInstall.txt

@@ -1246,6 +1246,8 @@ Release Notes/Change History
 
  * Removed use of deprecated ``md5`` module if ``hashlib`` is available
 
+ * Keep site directories (e.g. ``site-packages``) from being included in
+   ``.pth`` files.
 
 0.6c7
  * ``ftp:`` download URLs now work correctly.

setuptools/command/easy_install.py

@@ -272,7 +272,7 @@ class easy_install(Command):
 
         if is_site_dir:
             if self.pth_file is None:
-                self.pth_file = PthDistributions(pth_file)
+                self.pth_file = PthDistributions(pth_file, self.all_site_dirs)
         else:
             self.pth_file = None
 
@@ -1315,8 +1315,8 @@ class PthDistributions(Environment):
 
     dirty = False
 
-    def __init__(self, filename):
-        self.filename = filename
+    def __init__(self, filename, sitedirs=()):
+        self.filename = filename; self.sitedirs=map(normalize_path, sitedirs)
         self.basedir = normalize_path(os.path.dirname(self.filename))
         self._load(); Environment.__init__(self, [], None, None)
         for path in yield_lines(self.paths):
@@ -1325,7 +1325,7 @@ class PthDistributions(Environment):
     def _load(self):
         self.paths = []
         saw_import = False
-        seen = {}
+        seen = dict.fromkeys(self.sitedirs)
         if os.path.isfile(self.filename):
             for line in open(self.filename,'rt'):
                 if line.startswith('import'):
@@ -1381,7 +1381,7 @@ class PthDistributions(Environment):
 
     def add(self,dist):
         """Add `dist` to the distribution map"""
-        if dist.location not in self.paths:
+        if dist.location not in self.paths and dist.location not in self.sitedirs:
             self.paths.append(dist.location); self.dirty = True
         Environment.add(self,dist)