Problem: site-packages in sys.path before eggs

Solution: sort packages to push site-packages at the end

CHANGES.rst

@@ -4,6 +4,8 @@ Change History
 3.0.0 (unreleased)
 ==================
 
+- Scripts: ensure eggs are inserted before ``site-packages`` in ``sys.path``.
+
 - Fix forever loop when changing ``zc.buildout`` version via ``buildout``.
 
 - Add support for ``Requires-Python`` metadata.

src/zc/buildout/easy_install.py

@@ -1141,7 +1141,12 @@ def scripts(reqs, working_set, executable, dest=None,
             ):
     assert executable == sys.executable, (executable, sys.executable)
 
-    path = [dist.location for dist in working_set]
+    # ensure eggs are inserted before ``site-packages`` in ``sys.path``.
+    # TODO ensure develop-eggs are also inserted before ``site-packages``.
+    dists = [dist for dist in working_set]
+    dists.sort(key=lambda dist: (-dist.precedence, dist.project_name))
+
+    path = [dist.location for dist in dists]
     path.extend(extra_paths)
     # order preserving unique
     unique_path = []

src/zc/buildout/easy_install.txt

@@ -920,8 +920,8 @@ to pass a common base directory of the scripts and eggs:
     <BLANKLINE>
     import sys
     sys.path[0:0] = [
-      join(base, 'eggs/demoneeded-1.1-pyN.N.egg'),
       join(base, 'eggs/demo-0.3-pyN.N.egg'),
+      join(base, 'eggs/demoneeded-1.1-pyN.N.egg'),
       '/ba',
       join(base, 'bar'),
       base,
@@ -954,8 +954,8 @@ We specified an interpreter and its paths are adjusted too:
     import sys
     <BLANKLINE>
     sys.path[0:0] = [
-      join(base, 'eggs/demoneeded-1.1-pyN.N.egg'),
       join(base, 'eggs/demo-0.3-pyN.N.egg'),
+      join(base, 'eggs/demoneeded-1.1-pyN.N.egg'),
       '/ba',
       join(base, 'bar'),
       base,