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

@@ -310,6 +310,7 @@ class Buildout(DictMixin):
         self._raw = _unannotate(data)
         self._data = {}
         self._parts = []
+        self._initializing = []
 
         # provide some defaults before options are parsed
         # because while parsing options those attributes might be
@@ -839,14 +840,29 @@ class Buildout(DictMixin):
                     "Unexpected entry, %r, in develop-eggs directory.", f)
 
     def _compute_part_signatures(self, parts):
+        # The same recipe may appear many times.
+        sig_cache= {}
+
         # Compute recipe signature and add to options
         for part in parts:
             options = self.get(part)
             if options is None:
                 options = self[part] = {}
             recipe, entry = _recipe(options)
+
+            try:
+                # Copy cached list, because sig.append is called later
+                sig = sig_cache[recipe][:]
+            except KeyError:
                 req = pkg_resources.Requirement.parse(recipe)
-            sig = _dists_sig(pkg_resources.working_set.resolve([req]))
+                sig_result = sig_cache[recipe] = sorted(set(_dists_sig(pkg_resources.working_set.resolve([req]))))
+                sig = sig_result[:]
+
+            for dependency in sorted(options.depends):
+                m = md5()
+                for item in sorted(self[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):
@@ -1178,13 +1194,19 @@ class Buildout(DictMixin):
                     v = ' '+v
                 print_("%s =%s" % (k, v))
 
+    def initialize(self, options, reqs, entry):
+        recipe_class = _install_and_load(reqs, 'zc.buildout', entry, self)
+        self._initializing.append(options)
+        try:
+            return recipe_class(self, options.name, options)
+        finally:
+            del self._initializing[-1]
+
     def __getitem__(self, section):
         __doing__ = 'Getting section %s.', section
         try:
-            return self._data[section]
+            options = self._data[section]
         except KeyError:
-            pass
-
             try:
                 data = self._raw[section]
             except KeyError:
@@ -1193,6 +1215,11 @@ class Buildout(DictMixin):
             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):
@@ -1275,6 +1302,7 @@ class Options(DictMixin):
         self._raw = data
         self._cooked = {}
         self._data = {}
+        self.depends = set()
 
     def _initialize(self):
         name = self.name
@@ -1292,17 +1320,9 @@ class Options(DictMixin):
             return # buildout section can never be a part
 
         if self.get('recipe'):
-            self.initialize()
+            self.recipe = self.buildout.initialize(self, *_recipe(self._data))
             self.buildout._parts.append(name)
 
-    def initialize(self):
-        reqs, entry = _recipe(self._data)
-        buildout = self.buildout
-        recipe_class = _install_and_load(reqs, 'zc.buildout', entry, buildout)
-
-        name = self.name
-        self.recipe = recipe_class(buildout, name, self)
-
     def _do_extend_raw(self, name, data, doing):
         if name == 'buildout':
             return data
@@ -1409,7 +1429,14 @@ class Options(DictMixin):
             section, option = s
             if not section:
                 section = self.name
-            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/buildout.txt

@@ -2544,7 +2544,7 @@ 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
@@ -2574,7 +2574,7 @@ 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
 
@@ -2587,6 +2587,7 @@ 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.
@@ -2596,7 +2597,8 @@ 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::

src/zc/buildout/testing.py

@@ -179,18 +179,14 @@ def wait_until(label, func, *args, **kw):
         time.sleep(0.01)
     raise ValueError('Timed out waiting for: '+label)
 
-class TestOptions(zc.buildout.buildout.Options):
-
-    def initialize(self):
-        pass
-
 class Buildout(zc.buildout.buildout.Buildout):
 
     def __init__(self):
         zc.buildout.buildout.Buildout.__init__(
             self, '', [('buildout', 'directory', os.getcwd())])
 
-    Options = TestOptions
+    def initialize(self, *args):
+        pass
 
 def buildoutSetUp(test):
 

src/zc/buildout/tests.py

@@ -2089,6 +2089,80 @@ def dealing_with_extremely_insane_dependencies():
     Error: Couldn't find a distribution for 'pack5'.
     """
 
+def test_part_pulled_by_recipe():
+    """
+    >>> mkdir(sample_buildout, 'recipes')
+    >>> write(sample_buildout, 'recipes', 'test.py',
+    ... '''
+    ... class Recipe:
+    ...
+    ...     def __init__(self, buildout, name, options):
+    ...         self.x = buildout[options['x']][name]
+    ...
+    ...     def install(self):
+    ...         print self.x
+    ...         return ()
+    ...
+    ...     update = install
+    ... ''')
+
+
+    >>> write(sample_buildout, 'recipes', 'setup.py',
+    ... '''
+    ... from setuptools import setup
+    ... setup(
+    ...     name = "recipes",
+    ...     entry_points = {'zc.buildout': ['test = test:Recipe']},
+    ...     )
+    ... ''')
+
+    >>> write(sample_buildout, 'buildout.cfg',
+    ... '''
+    ... [buildout]
+    ... develop = recipes
+    ... parts = a
+    ... [a]
+    ... recipe = recipes:test
+    ... x = b
+    ... [b]
+    ... <= a
+    ... a = A
+    ... b = B
+    ... c = ${c:x}
+    ... [c]
+    ... x = c
+    ... ''')
+
+    >>> os.chdir(sample_buildout)
+    >>> buildout = os.path.join(sample_buildout, 'bin', 'buildout')
+
+    >>> print_(system(buildout), end='')
+    Develop: '/sample-buildout/recipes'
+    Installing b.
+    B
+    Installing a.
+    A
+
+    >>> print_(system(buildout), end='')
+    Develop: '/sample-buildout/recipes'
+    Updating b.
+    B
+    Updating a.
+    A
+
+    >>> cat('.installed.cfg') # doctest: +ELLIPSIS
+    [buildout]
+    ...
+    [b]
+    __buildout_installed__ = 
+    __buildout_signature__ = recipes-... c:...
+    ...
+    [a]
+    __buildout_installed__ = 
+    __buildout_signature__ = recipes-... b:...
+    ...
+    """
+
 def read_find_links_to_load_extensions():
     r"""
 We'll create a wacky buildout extension that just announces itself when used:

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

@@ -97,14 +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__ = ...
+    __buildout_signature__ = sample-... setuptools-...egg zc.buildout-... zc.recipe.egg-...
     _b = /sample-buildout/bin
     _d = /sample-buildout/develop-eggs
     _e = /sample-buildout/eggs