From ffc6dcf8d1e388720f22d4e6bfeb6816cb2bd668 Mon Sep 17 00:00:00 2001
From: Florian Friesdorf <flo@chaoflow.net>
Date: Thu, 8 Apr 2010 02:32:22 +0200
Subject: [PATCH 2/2] support environment variables as part of extends values

---
 src/zc/buildout/buildout.py |    5 +++++
 src/zc/buildout/tests.py    |   26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/src/zc/buildout/buildout.py b/src/zc/buildout/buildout.py
index eacc2be..00d6c10 100644
--- a/src/zc/buildout/buildout.py
+++ b/src/zc/buildout/buildout.py
@@ -1334,6 +1334,11 @@ def _open(base, filename, seen, dl_options, override):
         dl_options = _update_section(dl_options, result['buildout'])
 
     if extends:
+        extends = re.sub(
+                '\${env:([^}]+)}',
+                lambda m: os.environ[m.groups()[0]],
+                extends,
+                )
         extends = extends.split()
         eresult = _open(base, extends.pop(0), seen, dl_options, override)
         for fname in extends:
diff --git a/src/zc/buildout/tests.py b/src/zc/buildout/tests.py
index 1b03286..54f1523 100644
--- a/src/zc/buildout/tests.py
+++ b/src/zc/buildout/tests.py
@@ -2656,6 +2656,32 @@ def increment_buildout_with_multiple_extended_files_421022_and_envvars():
       recipe='zc.buildout:debug'
     """
 
+def env_vars_in_extends():
+    r"""
+    >>> write('foo.cfg', '''
+    ... [buildout]
+    ... foo-option = I
+    ... ''')
+    >>> write('buildout.cfg', '''
+    ... [buildout]
+    ... parts = other
+    ... extends = ${env:to_extend}.cfg
+    ... foo-option += am
+    ...
+    ... [other]
+    ... recipe = zc.buildout:debug
+    ... foo-option = ${env:foo} fine
+    ... ''')
+
+    >>> print system(buildout, env={
+    ...     'to_extend':'foo',
+    ...     'foo':'${buildout:foo-option}',
+    ...     }),
+    Installing other.
+      foo-option='I\nam fine'
+      recipe='zc.buildout:debug'
+    """
+
 def increment_on_command_line():
     r"""
     >>> write('buildout.cfg', '''
-- 
1.6.6.2