Added ConfigHandler.strict_mode.

2 files changed, 32 insertions, 4 deletions

diff --git a/setuptools/config.py b/setuptools/config.py
index 94b2ab17..3546ace9 100644
--- a/setuptools/config.py
+++ b/setuptools/config.py
@@ -12,6 +12,16 @@ class ConfigHandler(object):
     """Handles metadata supplied in configuration files."""
 
     section_prefix = None
+    """Prefix for config sections handled by this handler.
+    Must be provided by class heirs.
+
+    """
+
+    strict_mode = True
+    """Flag. Whether unknown options in config should
+    raise DistutilsOptionError exception, or pass silently.
+
+    """
 
     def __init__(self, target_obj, options):
         sections = {}
@@ -174,9 +184,11 @@ class ConfigHandler(object):
         for (name, (_, value)) in section_options.items():
             try:
                 self[name] = value
+
             except KeyError:
-                raise DistutilsOptionError(
-                    'Unknown distribution option: %s' % name)
+                if self.strict_mode:
+                    raise DistutilsOptionError(
+                        'Unknown distribution option: %s' % name)
 
     def parse(self):
         """Parses configuration file items from one
@@ -203,6 +215,11 @@ class ConfigHandler(object):
 class ConfigMetadataHandler(ConfigHandler):
 
     section_prefix = 'metadata'
+    strict_mode = False
+    """We need to keep it loose, to be compatible with `pbr` package
+    which also uses `metadata` section.
+
+    """
 
     @property
     def parsers(self):
diff --git a/setuptools/tests/test_config.py b/setuptools/tests/test_config.py
index d044cbac..f1b1aa3f 100644
--- a/setuptools/tests/test_config.py
+++ b/setuptools/tests/test_config.py
@@ -130,8 +130,7 @@ class TestMetadata:
             'unknown = some\n'
         )
         with get_dist(tmpdir, parse=False) as dist:
-            with pytest.raises(DistutilsOptionError):
-                dist.parse_config_files()
+            dist.parse_config_files()  # Skip unknown.
 
     def test_usupported_section(self, tmpdir):
 
@@ -274,6 +273,18 @@ class TestOptions:
         with get_dist(tmpdir) as dist:
             assert dist.packages == ['fake_package']
 
+    def test_unknown_options_item(self, tmpdir):
+
+        fake_env(
+            tmpdir,
+            '[options]\n'
+            'zip_safe = True\n'
+            'usr_2to3 = 1\n'
+        )
+        with get_dist(tmpdir, parse=False) as dist:
+            with pytest.raises(DistutilsOptionError):
+                dist.parse_config_files()
+
     def test_extras_require(self, tmpdir):
         fake_env(
             tmpdir,