Support on the fly patches in easy_install.

Version string is now N.N.N.postN to follow http://legacy.python.org/dev/peps/pep-0440/ .
(Ideally it should be N.N.N+SlapOSNNN, but version string containing '+' sign does now work
with older setuptools, that can be still used at the very beginning of bootstrap process.)

CHANGES.SlapOS.txt

+1.7.1.post6
+-----------
+
+- Version string is now N.N.N.postN to follow http://legacy.python.org/dev/peps/pep-0440/ .
+  (Ideally it should be N.N.N+SlapOSNNN, but version string containing '+' sign does now work
+  with older setuptools, that can be still used at the very beginning of bootstrap process.)
+- Support on the fly patches in easy_install.
+
 1.7.1-dev-SlapOS-005
 --------------------
 
@@ -74,7 +82,7 @@
 
 - Add support of networkcache for pypi index, extensions and recipes using
   buildout internals.
-    https://bugs.launchpad.net/zc.buildout/+bug/1041249
+  https://bugs.launchpad.net/zc.buildout/+bug/1041249
 
 1.6.0-dev-SlapOS-006
 --------------------

setup.py

@@ -12,7 +12,7 @@
 #
 ##############################################################################
 name = "zc.buildout"
-version = "1.7.1-dev-SlapOS-005"
+version = "1.7.1.post6"
 
 import os
 from setuptools import setup

src/zc/buildout/easy_install.py

@@ -78,6 +78,9 @@ BROKEN_DASH_S_WARNING = (
     'to the buildout script.  Alternatively, use a Python executable with a '
     'working -S (such as a standard Python binary).')
 
+PATCH_MARKER = 'SlapOSPatched'
+orig_versions_re = re.compile(r'[+\-]%s\d+' % PATCH_MARKER)
+
 if is_jython:
     import java.lang.System
     jython_os_name = (java.lang.System.getProperties()['os.name']).lower()
@@ -801,6 +804,11 @@ class Installer:
             shutil.rmtree(tmp)
 
     def _obtain(self, requirement, source=None):
+        # get the non-patched version
+        req = str(requirement)
+        if PATCH_MARKER in req:
+            requirement = pkg_resources.Requirement.parse(re.sub(orig_versions_re, '', req))
+
         # initialize out index for this project:
         index = self._index
 
@@ -1054,7 +1062,7 @@ class Installer:
 
         return requirement
 
-    def install(self, specs, working_set=None):
+    def install(self, specs, working_set=None, patch_dict=None):
 
         logger.debug('Installing %s.', repr(specs)[1:-1])
 
@@ -1074,6 +1082,9 @@ class Installer:
             ws = working_set
 
         for requirement in requirements:
+            if patch_dict and requirement.project_name in patch_dict:
+                self._env.scan(
+                    self.build(str(requirement), {}, patch_dict=patch_dict))
             for dist in self._get_dist(requirement, ws, self._always_unzip):
                 ws.add(dist)
                 self._maybe_add_setuptools(ws, dist)
@@ -1133,7 +1144,7 @@ class Installer:
                 logger.debug('Egg from site-packages: %s', dist)
         return ws
 
-    def build(self, spec, build_ext):
+    def build(self, spec, build_ext, patch_dict=None):
 
         requirement = self._constrain(pkg_resources.Requirement.parse(spec))
 
@@ -1177,12 +1188,31 @@ class Installer:
                             )
                     base = os.path.dirname(setups[0])
 
+                setup_cfg_dict = {'build_ext':build_ext}
+                patch_dict = (patch_dict or {}).get(re.sub('[<>=].*', '', spec))
+                if patch_dict:
+                    setup_cfg_dict.update(
+                      {'egg_info':{'tag_build':'+%s%03d' % (PATCH_MARKER,
+                                                            patch_dict['patch_revision'])}})
+                    for patch in patch_dict['patches']:
+                        url, md5sum = (patch.strip().split('#', 1) + [''])[:2]
+                        download = zc.buildout.download.Download()
+                        path, is_temp = download(url, md5sum=md5sum or None,
+                                                 path=os.path.join(tmp, 'patch'))
+                        args = [patch_dict['patch_binary']] + patch_dict['patch_options']
+                        kwargs = {'cwd':base,
+                                  'stdin':open(path)}
+                        popen = subprocess.Popen(args, **kwargs)
+                        popen.communicate()
+                        if popen.returncode != 0:
+                            raise subprocess.CalledProcessError(
+                                popen.returncode, ' '.join(args))
                 setup_cfg = os.path.join(base, 'setup.cfg')
                 if not os.path.exists(setup_cfg):
                     f = open(setup_cfg, 'w')
                     f.close()
                 setuptools.command.setopt.edit_config(
-                    setup_cfg, dict(build_ext=build_ext))
+                    setup_cfg, setup_cfg_dict)
 
                 dists = self._call_easy_install(
                     base, pkg_resources.WorkingSet(),
@@ -1265,7 +1295,7 @@ def install(specs, dest,
             upload_dir_url=None, upload_cache_url=None,
             signature_certificate_list=None, signature_private_key_file=None,
             shacache_cert_file=None, shacache_key_file=None,
-            shadir_cert_file=None, shadir_key_file=None):
+            shadir_cert_file=None, shadir_key_file=None, patch_dict=None):
     installer = Installer(
         dest, links, index, executable, always_unzip, path, newest,
         versions, use_dependency_links, allow_hosts=allow_hosts,
@@ -1280,20 +1310,21 @@ def install(specs, dest,
         shacache_key_file=shacache_key_file,
         shadir_cert_file=shadir_cert_file,
         shadir_key_file=shadir_key_file)
-    return installer.install(specs, working_set)
+    return installer.install(specs, working_set, patch_dict=patch_dict)
 
 
 def build(spec, dest, build_ext,
           links=(), index=None,
           executable=sys.executable,
           path=None, newest=True, versions=None, allow_hosts=('*',),
-          include_site_packages=None, allowed_eggs_from_site_packages=None):
+          include_site_packages=None, allowed_eggs_from_site_packages=None,
+          patch_dict=None):
     installer = Installer(
         dest, links, index, executable, True, path, newest, versions,
         allow_hosts=allow_hosts,
         include_site_packages=include_site_packages,
         allowed_eggs_from_site_packages=allowed_eggs_from_site_packages)
-    return installer.build(spec, build_ext)
+    return installer.build(spec, build_ext, patch_dict=patch_dict)