This allows additional commands to be provided for existing setup.py

scripts without modifying either the distutils installation or the
setup.py scripts of packages with which the new commands will be used.

Specifically, an option is added to distutils that allows additional
packages to be searched for command implementations in addition to
distutils.command.  The additional packages can be specified on the
command line or via the installation or personal configuration files
already loaded by distutils.

For discussion, see the thread starting with:

http://mail.python.org/pipermail/distutils-sig/2004-August/004112.html

This closes SF patch #102241.

dist.py

@@ -141,6 +141,14 @@ class Distribution:
         # for the setup script to override command classes
         self.cmdclass = {}
 
+        # 'command_packages' is a list of packages in which commands
+        # are searched for.  The factory for command 'foo' is expected
+        # to be named 'foo' in the module 'foo' in one of the packages
+        # named here.  This list is searched from the left; an error
+        # is raised if no named package provides the command being
+        # searched for.  (Always access using get_command_packages().)
+        self.command_packages = None
+
         # 'script_name' and 'script_args' are usually set to sys.argv[0]
         # and sys.argv[1:], but they can be overridden when the caller is
         # not necessarily a setup script run from the command-line.
@@ -406,6 +414,8 @@ class Distribution:
                         setattr(self, alias, not strtobool(val))
                     elif opt in ('verbose', 'dry_run'): # ugh!
                         setattr(self, opt, strtobool(val))
+                    else:
+                        setattr(self, opt, val)
                 except ValueError, msg:
                     raise DistutilsOptionError, msg
 
@@ -437,11 +447,12 @@ class Distribution:
         # We now have enough information to show the Macintosh dialog
         # that allows the user to interactively specify the "command line".
         #
+        toplevel_options = self._get_toplevel_options()
         if sys.platform == 'mac':
             import EasyDialogs
             cmdlist = self.get_command_list()
             self.script_args = EasyDialogs.GetArgv(
-                self.global_options + self.display_options, cmdlist)
+                toplevel_options + self.display_options, cmdlist)
 
         # We have to parse the command line a bit at a time -- global
         # options, then the first command, then its options, and so on --
@@ -451,7 +462,7 @@ class Distribution:
         # until we know what the command is.
 
         self.commands = []
-        parser = FancyGetopt(self.global_options + self.display_options)
+        parser = FancyGetopt(toplevel_options + self.display_options)
         parser.set_negative_aliases(self.negative_opt)
         parser.set_aliases({'licence': 'license'})
         args = parser.getopt(args=self.script_args, object=self)
@@ -488,6 +499,17 @@ class Distribution:
 
     # parse_command_line()
 
+    def _get_toplevel_options (self):
+        """Return the non-display options recognized at the top level.
+
+        This includes options that are recognized *only* at the top
+        level as well as options recognized for commands.
+        """
+        return self.global_options + [
+            ("command-packages=", None,
+             "list of packages that provide distutils commands"),
+            ]
+
     def _parse_command_opts (self, parser, args):
         """Parse the command-line options for a single command.
         'parser' must be a FancyGetopt instance; 'args' must be the list
@@ -586,7 +608,6 @@ class Distribution:
 
     # _parse_command_opts ()
 
-
     def finalize_options (self):
         """Set final values for all the options on the Distribution
         instance, analogous to the .finalize_options() method of Command
@@ -627,7 +648,11 @@ class Distribution:
         from distutils.cmd import Command
 
         if global_options:
-            parser.set_option_table(self.global_options)
+            if display_options:
+                options = self._get_toplevel_options()
+            else:
+                options = self.global_options
+            parser.set_option_table(options)
             parser.print_help("Global options:")
             print
 
@@ -791,6 +816,19 @@ class Distribution:
 
     # -- Command class/object methods ----------------------------------
 
+    def get_command_packages (self):
+        """Return a list of packages from which commands are loaded."""
+        pkgs = self.command_packages
+        if not isinstance(pkgs, type([])):
+            pkgs = string.split(pkgs or "", ",")
+            for i in range(len(pkgs)):
+                pkgs[i] = string.strip(pkgs[i])
+            pkgs = filter(None, pkgs)
+            if "distutils.command" not in pkgs:
+                pkgs.insert(0, "distutils.command")
+            self.command_packages = pkgs
+        return pkgs
+
     def get_command_class (self, command):
         """Return the class that implements the Distutils command named by
         'command'.  First we check the 'cmdclass' dictionary; if the
@@ -807,26 +845,28 @@ class Distribution:
         if klass:
             return klass
 
-        module_name = 'distutils.command.' + command
-        klass_name = command
+        for pkgname in self.get_command_packages():
+            module_name = "%s.%s" % (pkgname, command)
+            klass_name = command
 
-        try:
-            __import__ (module_name)
-            module = sys.modules[module_name]
-        except ImportError:
-            raise DistutilsModuleError, \
-                  "invalid command '%s' (no module named '%s')" % \
-                  (command, module_name)
+            try:
+                __import__ (module_name)
+                module = sys.modules[module_name]
+            except ImportError:
+                continue
+
+            try:
+                klass = getattr(module, klass_name)
+            except AttributeError:
+                raise DistutilsModuleError, \
+                      "invalid command '%s' (no class '%s' in module '%s')" \
+                      % (command, klass_name, module_name)
+
+            self.cmdclass[command] = klass
+            return klass
+
+        raise DistutilsModuleError("invalid command '%s'" % command)
 
-        try:
-            klass = getattr(module, klass_name)
-        except AttributeError:
-            raise DistutilsModuleError, \
-                  "invalid command '%s' (no class '%s' in module '%s')" \
-                  % (command, klass_name, module_name)
-
-        self.cmdclass[command] = klass
-        return klass
 
     # get_command_class ()
 

tests/test_dist.py

+"""Tests for distutils.dist."""
+
+import distutils.cmd
+import distutils.dist
+import os
+import shutil
+import sys
+import tempfile
+import unittest
+
+from test.test_support import TESTFN
+
+
+class test_dist(distutils.cmd.Command):
+    """Sample distutils extension command."""
+
+    user_options = [
+        ("sample-option=", "S", "help text"),
+        ]
+
+    def initialize_options(self):
+        self.sample_option = None
+
+
+class TestDistribution(distutils.dist.Distribution):
+    """Distribution subclasses that avoids the default search for
+    configuration files.
+
+    The ._config_files attribute must be set before
+    .parse_config_files() is called.
+    """
+
+    def find_config_files(self):
+        return self._config_files
+
+
+class DistributionTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.argv = sys.argv[:]
+        del sys.argv[1:]
+
+    def tearDown(self):
+        sys.argv[:] = self.argv
+
+    def create_distribution(self, configfiles=()):
+        d = TestDistribution()
+        d._config_files = configfiles
+        d.parse_config_files()
+        d.parse_command_line()
+        return d
+
+    def test_command_packages_unspecified(self):
+        sys.argv.append("build")
+        d = self.create_distribution()
+        self.assertEqual(d.get_command_packages(), ["distutils.command"])
+
+    def test_command_packages_cmdline(self):
+        sys.argv.extend(["--command-packages",
+                         "foo.bar,distutils.tests",
+                         "test_dist",
+                         "-Ssometext",
+                         ])
+        d = self.create_distribution()
+        # let's actually try to load our test command:
+        self.assertEqual(d.get_command_packages(),
+                         ["distutils.command", "foo.bar", "distutils.tests"])
+        cmd = d.get_command_obj("test_dist")
+        self.assert_(isinstance(cmd, test_dist))
+        self.assertEqual(cmd.sample_option, "sometext")
+
+    def test_command_packages_configfile(self):
+        sys.argv.append("build")
+        f = open(TESTFN, "w")
+        try:
+            print >>f, "[global]"
+            print >>f, "command_packages = foo.bar, splat"
+            f.close()
+            d = self.create_distribution([TESTFN])
+            self.assertEqual(d.get_command_packages(),
+                             ["distutils.command", "foo.bar", "splat"])
+
+            # ensure command line overrides config:
+            sys.argv[1:] = ["--command-packages", "spork", "build"]
+            d = self.create_distribution([TESTFN])
+            self.assertEqual(d.get_command_packages(),
+                             ["distutils.command", "spork"])
+
+            # Setting --command-packages to '' should cause the default to
+            # be used even if a config file specified something else:
+            sys.argv[1:] = ["--command-packages", "", "build"]
+            d = self.create_distribution([TESTFN])
+            self.assertEqual(d.get_command_packages(), ["distutils.command"])
+
+        finally:
+            os.unlink(TESTFN)
+
+
+def test_suite():
+    return unittest.makeSuite(DistributionTestCase)