`read_configuration()` now accepts `ignore_option_errors`.

docs/setuptools.txt

@@ -2543,7 +2543,7 @@ zip_safe                 bool
 setup_requires           list-semi
 install_requires         list-semi
 extras_require           section
-entry_points             file, section
+entry_points             file:, section
 use_2to3                 bool
 use_2to3_fixers          list-comma
 use_2to3_exclude_fixers  list-comma
@@ -2582,6 +2582,12 @@ in the first argument. To include values from other configuration files
 which could be in various places set `find_others` function argument
 to ``True``.
 
+If you have only a configuration file but not the whole package you can still
+try to get data out of it with the help of `ignore_option_errors` function
+argument. When it is set to ``True`` all options with errors possibly produced
+by directives, such as ``attr:`` and others will be silently ignored.
+As a consequence the resulting dictionary will include no such options.
+
 
 --------------------------------
 Extending and Reusing Setuptools

setuptools/config.py

@@ -10,7 +10,8 @@ from setuptools.py26compat import import_module
 from setuptools.extern.six import string_types
 
 
-def read_configuration(filepath, find_others=False):
+def read_configuration(
+        filepath, find_others=False, ignore_option_errors=False):
     """Read given configuration file and returns options from it as a dict.
 
     :param str|unicode filepath: Path to configuration file
@@ -19,6 +20,11 @@ def read_configuration(filepath, find_others=False):
     :param bool find_others: Whether to search for other configuration files
         which could be on in various places.
 
+    :param bool ignore_option_errors: Whether to silently ignore
+        options, values of which could not be resolved (e.g. due to exceptions
+        in directives such as file:, attr:, etc.).
+        If False exceptions are propagated as expected.
+
     :rtype: dict
     """
     from setuptools.dist import Distribution, _Distribution
@@ -40,7 +46,9 @@ def read_configuration(filepath, find_others=False):
 
     _Distribution.parse_config_files(dist, filenames=filenames)
 
-    handlers = parse_configuration(dist, dist.command_options)
+    handlers = parse_configuration(
+        dist, dist.command_options,
+        ignore_option_errors=ignore_option_errors)
 
     os.chdir(current_directory)
 
@@ -76,7 +84,8 @@ def configuration_to_dict(handlers):
     return config_dict
 
 
-def parse_configuration(distribution, command_options):
+def parse_configuration(
+        distribution, command_options, ignore_option_errors=False):
     """Performs additional parsing of configuration options
     for a distribution.
 
@@ -84,12 +93,18 @@ def parse_configuration(distribution, command_options):
 
     :param Distribution distribution:
     :param dict command_options:
+    :param bool ignore_option_errors: Whether to silently ignore
+        options, values of which could not be resolved (e.g. due to exceptions
+        in directives such as file:, attr:, etc.).
+        If False exceptions are propagated as expected.
     :rtype: list
     """
-    meta = ConfigMetadataHandler(distribution.metadata, command_options)
+    meta = ConfigMetadataHandler(
+        distribution.metadata, command_options, ignore_option_errors)
     meta.parse()
 
-    options = ConfigOptionsHandler(distribution, command_options)
+    options = ConfigOptionsHandler(
+        distribution, command_options, ignore_option_errors)
     options.parse()
 
     return [meta, options]
@@ -111,7 +126,7 @@ class ConfigHandler(object):
 
     """
 
-    def __init__(self, target_obj, options):
+    def __init__(self, target_obj, options, ignore_option_errors=False):
         sections = {}
 
         section_prefix = self.section_prefix
@@ -122,6 +137,7 @@ class ConfigHandler(object):
             section_name = section_name.replace(section_prefix, '').strip('.')
             sections[section_name] = section_options
 
+        self.ignore_option_errors = ignore_option_errors
         self.target_obj = target_obj
         self.sections = sections
         self.set_options = []
@@ -148,9 +164,19 @@ class ConfigHandler(object):
             # Already inhabited. Skipping.
             return
 
+        skip_option = False
         parser = self.parsers.get(option_name)
         if parser:
-            value = parser(value)
+            try:
+                value = parser(value)
+
+            except Exception:
+                skip_option = True
+                if not self.ignore_option_errors:
+                    raise
+
+        if skip_option:
+            return
 
         setter = getattr(target_obj, 'set_%s' % option_name, None)
         if setter is None:

setuptools/tests/test_config.py

@@ -73,6 +73,22 @@ class TestConfigurationReader:
         with pytest.raises(DistutilsFileError):
             read_configuration('%s' % tmpdir.join('setup.cfg'))
 
+    def test_ignore_errors(self, tmpdir):
+        fake_env(
+            tmpdir,
+            '[metadata]\n'
+            'version = attr: none.VERSION\n'
+            'keywords = one, two\n'
+        )
+        with pytest.raises(ImportError):
+            read_configuration('%s' % tmpdir.join('setup.cfg'))
+
+        config_dict = read_configuration(
+            '%s' % tmpdir.join('setup.cfg'), ignore_option_errors=True)
+
+        assert config_dict['metadata']['keywords'] == ['one', 'two']
+        assert 'version' not in config_dict['metadata']
+
 
 class TestMetadata: