Make sure buildout uses zc.recipe.egg>=2.0.0a3, which mainly matters

for Python 3.

CHANGES.rst

@@ -13,6 +13,9 @@ Change History
 - Versions in versions sections can now be simple constraints, like
   >=2.0dev in addition to being simple versions.
 
+  Buildout 2 leverages this to make sure it used
+  zc.recipe.egg>=2.0.0a3, which mainly matters for Python 3.
+
 2.0.0a4 (2012-11-19)
 ====================
 

src/zc/buildout/buildout.py

@@ -286,7 +286,7 @@ class Buildout(DictMixin):
                 self._error('Invalid value for newest option: %s', newest)
         self.newest = (newest == 'true')
 
-        versions = {}
+        versions = {'zc.recipe.egg': '>=2.0.0a3'}
         self.versions = versions
         versions_section = options.get('versions')
         if versions_section:

src/zc/buildout/buildout.txt

@@ -2578,8 +2578,8 @@ or paths to use:
     >>> remove('setup.cfg')
     >>> print_(system(buildout + ' -csetup.cfg init demo other ./src'), end='')
     Creating '/sample-bootstrapped/setup.cfg'.
-    Getting distribution for 'zc.recipe.egg'.
-    Got zc.recipe.egg 1.3.3dev.
+    Getting distribution for 'zc.recipe.egg>=2.0.0a3'.
+    Got zc.recipe.egg
     Installing py.
     Getting distribution for 'demo'.
     Got demo 0.3.

src/zc/buildout/tests.py

@@ -2695,6 +2695,27 @@ def test_constrained_requirement():
     ...         print_('failed', o, c, g, '!=', e)
     """
 
+def want_new_zcrecipeegg():
+    """
+    >>> write('buildout.cfg',
+    ... '''
+    ... [buildout]
+    ... parts = egg
+    ... [egg]
+    ... recipe = zc.recipe.egg <2dev
+    ... eggs = demo
+    ... ''')
+    >>> print_(system(join('bin', 'buildout')), end='') # doctest: +ELLIPSIS
+    The constraint, >=2.0.0a3,...
+    While:
+      Installing.
+      Getting section egg.
+      Initializing section egg.
+      Installing recipe zc.recipe.egg <2dev.
+    Error: Bad constraint >=2.0.0a3 zc.recipe.egg<2dev
+    """
+
+
 ######################################################################
 
 def create_sample_eggs(test, executable=sys.executable):