Support namespace packages in conjunction with system packagers, by omitting

the installation of any ``__init__.py`` files for namespace packages, and
adding a special ``.pth`` file to create a working package in ``sys.modules``.

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4043119

setuptools.txt

@@ -1225,21 +1225,18 @@ packages), in a normal Python package layout.  These ``__init__.py`` files
 This code ensures that the namespace package machinery is operating and that
 the current package is registered as a namespace package.
 
-You can include other code and data in a namespace package's ``__init__.py``,
-but it's generally not a great idea because the loading order of each
-project's namespace packages is not guaranteed, and thus the actual contents
-of the parent package at runtime may vary from one machine to another.  While
-it's true that you won't have such conflicts if only one project defines the
-contents of a particular namespace package's ``__init__.py``, it's less error-
-prone to just leave ``__init__.py`` empty except for the declaration line.
-
-(Note that this non-deterministic ordering also means that you must include
-the declaration line in the ``__init__.py`` of *every* project that has
-contents for the namespace package in question, in order to ensure that the
-namespace will be declared regardless of which project's copy of
-``__init__.py`` is loaded first.  If the first loaded ``__init__.py`` doesn't
-declare it, it will never *be* declared, because no other copies will ever be
-loaded!)
+You must NOT include any other code and data in a namespace package's
+``__init__.py``.  Even though it may appear to work during development, or when
+projects are installed as ``.egg`` files, it will not work when the projects
+are installed using "system" packaging tools -- in such cases the
+``__init__.py`` files will not be installed, let alone executed.
+
+You must include the ``declare_namespace()``  line in the ``__init__.py`` of
+*every* project that has contents for the namespace package in question, in
+order to ensure that the namespace will be declared regardless of which
+project's copy of ``__init__.py`` is loaded first.  If the first loaded
+``__init__.py`` doesn't declare it, it will never *be* declared, because no
+other copies will ever be loaded!)
 
 
 TRANSITIONAL NOTE
@@ -2352,6 +2349,11 @@ Release Notes/Change History
 ----------------------------
 
 0.6a11
+ * Support namespace packages in conjunction with system packagers, by omitting
+   the installation of any ``__init__.py`` files for namespace packages, and
+   adding a special ``.pth`` file to create a working package in
+   ``sys.modules``.
+
  * Made ``--single-version-externally-managed`` automatic when ``--root`` is
    used, so that most system packagers won't require special support for
    setuptools.

setuptools/command/easy_install.py

@@ -1288,6 +1288,8 @@ def get_exe_prefixes(exe_filename):
                     break
             if len(parts)<>2 or not name.endswith('.pth'):
                 continue
+            if name.endswith('-nspkg.pth'):
+                continue
             if parts[0] in ('PURELIB','PLATLIB'):
                 pth = z.read(name).strip()
                 prefixes[0] = ('PURELIB/%s/' % pth), ''
@@ -1308,8 +1310,6 @@ def parse_requirement_arg(spec):
         )
 
 
-
-
 class PthDistributions(Environment):
     """A .pth file with Distribution paths in it"""
 

setuptools/command/install_egg_info.py

@@ -37,7 +37,7 @@ class install_egg_info(Command):
         self.execute(self.copytree, (),
             "Copying %s to %s" % (self.source, self.target)
         )
-
+        self.install_namespaces()
 
     def get_outputs(self):
         return self.outputs
@@ -58,25 +58,25 @@ class install_egg_info(Command):
 
         unpack_archive(self.source, self.target, skimmer)
 
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+    def install_namespaces(self):
+        nsp = (self.distribution.namespace_packages or [])[:]
+        if not nsp: return
+        nsp.sort()  # set up shorter names first
+        filename,ext = os.path.splitext(self.target)
+        filename += '-nspkg.pth'; self.outputs.append(filename)
+        log.info("Installing %s",filename)
+        if not self.dry_run:
+            f = open(filename,'wb')
+            for pkg in nsp:
+                pth = tuple(pkg.split('.'))
+                f.write(
+                    "import sys,new; "
+                    "m = sys.modules.setdefault(%(pkg)r,new.module(%(pkg)r)); "
+                    "p = os.path.join(sys._getframe(1).f_locals['sitedir'], "
+                    "*%(pth)r); "
+                    "mp = m.__path__ = getattr(m,'__path__',[]); "
+                    "(p not in mp) and mp.append(p)\n"
+                    % locals()
+                )
+            f.close()            
 

setuptools/command/install_lib.py

 from distutils.command.install_lib import install_lib as _install_lib
+import os
 
 class install_lib(_install_lib):
     """Don't add compiled flags to filenames of non-Python files"""
@@ -15,7 +16,6 @@ class install_lib(_install_lib):
 
         return bytecode_files
 
-
     def run(self):
         self.build()
         outfiles = self.install()
@@ -23,3 +23,60 @@ class install_lib(_install_lib):
             # always compile, in case we have any extension stubs to deal with
             self.byte_compile(outfiles)
 
+    def get_exclusions(self):
+        exclude = {}
+        nsp = self.distribution.namespace_packages
+
+        if (nsp and self.get_finalized_command('install')
+               .single_version_externally_managed
+        ):
+            for pkg in nsp:
+                parts = pkg.split('.')
+                while parts:
+                    pkgdir = os.path.join(self.install_dir, *parts)
+                    for f in '__init__.py', '__init__.pyc', '__init__.pyo':
+                        exclude[os.path.join(pkgdir,f)] = 1
+                    parts.pop()
+        return exclude
+
+    def copy_tree(
+        self, infile, outfile,
+        preserve_mode=1, preserve_times=1, preserve_symlinks=0, level=1
+    ):
+        assert preserve_mode and preserve_times and not preserve_symlinks
+        exclude = self.get_exclusions()
+
+        if not exclude:
+            return _install_lib.copy_tree(self, infile, outfile)
+
+        # Exclude namespace package __init__.py* files from the output
+
+        from setuptools.archive_util import unpack_directory
+        from distutils import log
+
+        outfiles = []
+
+        def pf(src, dst):
+            if dst in exclude:
+                log.warn("Skipping installation of %s (namespace package)",dst)
+                return False
+
+            log.info("copying %s -> %s", src, os.path.dirname(dst))
+            outfiles.append(dst)
+            return dst
+
+        unpack_directory(infile, outfile, pf)
+        return outfiles
+
+    def get_outputs(self):
+        outputs = _install_lib.get_outputs(self)
+        exclude = self.get_exclusions()
+        if exclude:
+            return [f for f in outputs if f not in exclude]
+        return outputs
+
+
+
+
+
+