avoid sandbox violations on installation fixes #100

--HG--
branch : distribute
extra : rebase_source : 30a4c67f59ad25edf59133af2986191265811635

CHANGES.txt

@@ -26,6 +26,8 @@ CHANGES
   anymore under py3 with C or POSIX local. Contributed by Arfrever.
 * Issue 104: remvoved the assertion when the installation fails,
   with a nicer message for the end user.
+* Issue 100: making sure there's no SandboxViolation when
+  the setup script patches setuptools.
 
 -----
 0.6.8

distribute_setup.py

@@ -224,22 +224,34 @@ def _patch_file(path, content):
 def _same_content(path, content):
     return open(path).read() == content
 
+def _no_sandbox(function):
+    def __no_sandbox(*args, **kw):
+        try:
+            from setuptools.sandbox import DirectorySandbox
+            def violation(*args):
+                pass
+            DirectorySandbox._old = DirectorySandbox._violation
+            DirectorySandbox._violation = violation
+            patched = True
+        except ImportError:
+            patched = False
 
+        try:
+            return function(*args, **kw)
+        finally:
+            if patched:
+                DirectorySandbox._violation = DirectorySandbox._old
+                del DirectorySandbox._old
+
+    return __no_sandbox
+
+@_no_sandbox
 def _rename_path(path):
     new_name = path + '.OLD.%s' % time.time()
     log.warn('Renaming %s into %s', path, new_name)
-    try:
-        from setuptools.sandbox import DirectorySandbox
-        def _violation(*args):
-            pass
-        DirectorySandbox._violation = _violation
-    except ImportError:
-        pass
-
     os.rename(path, new_name)
     return new_name
 
-
 def _remove_flat_installation(placeholder):
     if not os.path.isdir(placeholder):
         log.warn('Unkown installation at %s', placeholder)
@@ -279,6 +291,7 @@ def _after_install(dist):
     placeholder = dist.get_command_obj('install').install_purelib
     _create_fake_setuptools_pkg_info(placeholder)
 
+@_no_sandbox
 def _create_fake_setuptools_pkg_info(placeholder):
     if not placeholder or not os.path.exists(placeholder):
         log.warn('Could not find the install location')
@@ -290,12 +303,14 @@ def _create_fake_setuptools_pkg_info(placeholder):
     if os.path.exists(pkg_info):
         log.warn('%s already exists', pkg_info)
         return
+
     log.warn('Creating %s', pkg_info)
     f = open(pkg_info, 'w')
     try:
         f.write(SETUPTOOLS_PKG_INFO)
     finally:
         f.close()
+
     pth_file = os.path.join(placeholder, 'setuptools.pth')
     log.warn('Creating %s', pth_file)
     f = open(pth_file, 'w')
@@ -304,7 +319,6 @@ def _create_fake_setuptools_pkg_info(placeholder):
     finally:
         f.close()
 
-
 def _patch_egg_dir(path):
     # let's check if it's already patched
     pkg_info = os.path.join(path, 'EGG-INFO', 'PKG-INFO')