Add referred parts' hash strings in __buildout_signature__, that invokes...

Add referred parts' hash strings in __buildout_signature__, that invokes rebuild of a part when one of its (recursive) dependencies are modified.

Also remove duplicates and sort entries in __buildout_signature__.

src/zc/buildout/buildout.py

@@ -866,7 +866,12 @@ class Buildout(DictMixin):
                 options = self[part] = {}
             recipe, entry = _recipe(options)
             req = pkg_resources.Requirement.parse(recipe)
-            sig = _dists_sig(pkg_resources.working_set.resolve([req]))
+            sig = sorted(set(_dists_sig(pkg_resources.working_set.resolve([req]))))
+            for dependency in sorted(getattr(options, '_dependency', ())):
+                m = md5()
+                for item in sorted(self.get(dependency).items()):
+                    m.update(('%r\0%r\0' % item).encode())
+                sig.append('%s:%s' % (dependency, m.hexdigest()))
             options['__buildout_signature__'] = ' '.join(sig)
 
     def _read_installed_part_options(self):
@@ -1274,6 +1279,7 @@ class Options(DictMixin):
         self._raw = data
         self._cooked = {}
         self._data = {}
+        self._dependency = set()
 
     def _initialize(self):
         name = self.name
@@ -1400,6 +1406,8 @@ class Options(DictMixin):
             section, option = s
             if not section:
                 section = self.name
+            elif section != 'buildout':
+                self._dependency.add(section)
             v = self.buildout[section].get(option, None, seen)
             if v is None:
                 if option == '_buildout_section_name_':

src/zc/buildout/buildout.txt

@@ -2529,7 +2529,7 @@ were created.
 The .installed.cfg is only updated for the recipes that ran:
 
     >>> cat(sample_buildout, '.installed.cfg')
-    ... # doctest: +NORMALIZE_WHITESPACE
+    ... # doctest: +NORMALIZE_WHITESPACE +ELLIPSIS
     [buildout]
     installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
     parts = debug d1 d2 d3 d4
@@ -2559,7 +2559,7 @@ The .installed.cfg is only updated for the recipes that ran:
     <BLANKLINE>
     [d4]
     __buildout_installed__ = /sample-buildout/data2-extra
-    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
+    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg== d2:...
     path = /sample-buildout/data2-extra
     recipe = recipes:mkdir
 
@@ -2571,6 +2571,7 @@ Now, if we run the buildout without the install command:
 
     >>> print_(system(buildout), end='')
     Develop: '/sample-buildout/recipes'
+    Uninstalling d4.
     Uninstalling d2.
     Uninstalling d1.
     Uninstalling debug.
@@ -2580,7 +2581,8 @@ Now, if we run the buildout without the install command:
     Installing d2.
     d2: Creating directory data2
     Updating d3.
-    Updating d4.
+    Installing d4.
+    d4: Creating directory data2-extra
 
 We see the output of the debug recipe and that data2 was created.  We
 also see that d1 and d2 have gone away:

zc.recipe.egg_/src/zc/recipe/egg/api.rst

@@ -97,17 +97,14 @@ of extra requirements to be included in the working set.
 We can see that the options were augmented with additional data
 computed by the egg recipe by looking at .installed.cfg:
 
-    >>> cat(sample_buildout, '.installed.cfg')
+    >>> cat(sample_buildout, '.installed.cfg') # doctest: +ELLIPSIS
     [buildout]
     installed_develop_eggs = /sample-buildout/develop-eggs/sample.egg-link
     parts = sample-part
     <BLANKLINE>
     [sample-part]
     __buildout_installed__ = 
-    __buildout_signature__ = sample-6aWMvV2EJ9Ijq+bR8ugArQ==
-            zc.recipe.egg-cAsnudgkduAa/Fd+WJIM6Q==
-            setuptools-0.7-py2.4.egg
-            zc.buildout-+rYeCcmFuD1K/aB77XTj5A==
+    __buildout_signature__ = sample-... setuptools-...egg zc.buildout-... zc.recipe.egg-...
     _b = /sample-buildout/bin
     _d = /sample-buildout/develop-eggs
     _e = /sample-buildout/eggs