fixup! In __buildout_signature__, fix missing parts that are pulled by recipes' __init__

src/zc/buildout/buildout.py

@@ -1282,23 +1282,22 @@ class Buildout(DictMixin):
 
     def __getitem__(self, section):
         __doing__ = 'Getting section %s.', section
-        if self._initializing:
-            caller = self._initializing[-1]
-            if 'buildout' != section != caller.name:
-                  caller.depends.add(section)
         try:
-            return self._data[section]
+            options = self._data[section]
         except KeyError:
-            pass
+            try:
+                data = self._raw[section]
+            except KeyError:
+                raise MissingSection(section)
 
-        try:
-            data = self._raw[section]
-        except KeyError:
-            raise MissingSection(section)
+            options = self.Options(self, section, data)
+            self._data[section] = options
+            options._initialize()
 
-        options = self.Options(self, section, data)
-        self._data[section] = options
-        options._initialize()
+        if self._initializing:
+            caller = self._initializing[-1]
+            if 'buildout' != section != caller.name:
+                  caller.depends.add(section)
         return options
 
     def __setitem__(self, name, data):
@@ -1508,12 +1507,14 @@ class Options(DictMixin):
             section, option = s
             if not section:
                 section = self.name
-            elif section != 'buildout':
-                assert not self.buildout._initializing, (self.name,
-                    self.buildout._initializing[-1],
-                    len(self.buildout._initializing))
-                self.depends.add(section)
-            v = self.buildout[section].get(option, None, seen, last=last)
+                options = self
+            else:
+                self.buildout._initializing.append(self)
+                try:
+                    options = self.buildout[section]
+                finally:
+                    del self.buildout._initializing[-1]
+            v = options.get(option, None, seen, last=last)
             if v is None:
                 if option == '_buildout_section_name_':
                     v = self.name

src/zc/buildout/tests.py

@@ -2118,6 +2118,9 @@ def test_part_pulled_by_recipe():
     ... <= a
     ... a = A
     ... b = B
+    ... c = ${c:x}
+    ... [c]
+    ... x = c
     ... ''')
 
     >>> os.chdir(sample_buildout)
@@ -2142,7 +2145,7 @@ def test_part_pulled_by_recipe():
     ...
     [b]
     __buildout_installed__ = 
-    __buildout_signature__ = recipes-c79aac86a90182467ce2fdae8b56eb1c
+    __buildout_signature__ = recipes-c79aac86a90182467ce2fdae8b56eb1c c:...
     ...
     [a]
     __buildout_installed__ =