Merge branch 'bug_605017'

Conflicts:
	src/zc/buildout/tests.py

src/zc/buildout/buildout.py

@@ -1312,6 +1312,7 @@ class Options(UserDict.DictMixin):
 
         if '<' in self._raw:
             self._raw = self._do_extend_raw(name, self._raw, [])
+            self._raw.pop('<')
 
         # force substitutions
         for k, v in self._raw.items():
@@ -1340,7 +1341,7 @@ class Options(UserDict.DictMixin):
             raise zc.buildout.UserError("Infinite extending loop %r" % name)
         doing.append(name)
         try:
-            to_do = data.pop('<', None)
+            to_do = data.get('<', None)
             if to_do is None:
                 return data
             __doing__ = 'Loading input sections for %r', name

src/zc/buildout/tests.py

@@ -3702,6 +3702,102 @@ def bug_664539_recipe_updating_options_dict():
     data='${value}'
     recipe='zc.buildout:debug'
   """
+def test_other_section_extend_precedence():
+    r"""
+    >>> write('buildout.cfg', '''
+    ... [buildout]
+    ... parts = myfiles
+    ...
+    ... [debug]
+    ... recipe = zc.buildout:debug
+    ... file1 = ${:path}/file1
+    ... color = red
+    ...
+    ... [myfiles]
+    ... <= debug
+    ... path = mydata
+    ... color = green
+    ... ''')
+
+    >>> print system(buildout),
+    Installing myfiles.
+      color='green'
+      file1='mydata/file1'
+      path='mydata'
+      recipe='zc.buildout:debug'
+    """
+
+def test_same_section_extend_precedence():
+    r"""
+    >>> write('bar.cfg', '''
+    ... [myfiles]
+    ... recipe = zc.buildout:debug
+    ... file1 = ${:path}/file1
+    ... color = red
+    ... ''')
+    >>> write('buildout.cfg', '''
+    ... [buildout]
+    ... extends = bar.cfg
+    ... parts = myfiles
+    ...
+    ... [myfiles]
+    ... path = mydata
+    ... color = green
+    ... ''')
+
+    >>> print system(buildout),
+    Installing myfiles.
+      color='green'
+      file1='mydata/file1'
+      path='mydata'
+      recipe='zc.buildout:debug'
+    """
+
+def bug_605017_reuse_extending_section():
+    r"""
+    >>> write('buildout.cfg', '''
+    ... [buildout]
+    ... parts = myfiles
+    ...   myfiles2
+    ...
+    ... [debug]
+    ... recipe = zc.buildout:debug
+    ...
+    ... [with_file1]
+    ... <= debug
+    ... file1 = ${:path}/file1
+    ... color = red
+    ...
+    ... [with_file2]
+    ... <= debug
+    ... file2 = ${:path}/file2
+    ... color = blue
+    ...
+    ... [myfiles]
+    ... <= with_file1
+    ...    with_file2
+    ... path = mydata
+    ...
+    ... [myfiles2]
+    ... <= with_file1
+    ...    with_file2
+    ... path = mydata2
+    ... ''')
+
+    >>> print system(buildout),
+    Installing myfiles.
+      color='blue'
+      file1='mydata/file1'
+      file2='mydata/file2'
+      path='mydata'
+      recipe='zc.buildout:debug'
+    Installing myfiles2.
+      color='blue'
+      file1='mydata2/file1'
+      file2='mydata2/file2'
+      path='mydata2'
+      recipe='zc.buildout:debug'
+    """
 
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