Merge default

1 files changed, 18 insertions, 15 deletions

diff --git a/distutils2/metadata.py b/distutils2/metadata.py
index 00be03b..efcfe32 100644
--- a/distutils2/metadata.py
+++ b/distutils2/metadata.py
@@ -34,6 +34,8 @@ try:
 
         def system_message(self, level, message, *children, **kwargs):
             self.messages.append((level, message, children, kwargs))
+            return nodes.system_message(message, level=level, type=self.
+                                        levels[level], *children, **kwargs)
 
     _HAS_DOCUTILS = True
 except ImportError:
@@ -48,7 +50,7 @@ PKG_INFO_ENCODING = 'utf-8'
 
 # preferred version. Hopefully will be changed
 # to 1.2 once PEP 345 is supported everywhere
-PKG_INFO_PREFERRED_VERSION = '1.0'
+PKG_INFO_PREFERRED_VERSION = '1.1'
 
 _LINE_PREFIX = re.compile('\n       \|')
 _241_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
@@ -101,7 +103,12 @@ def _best_version(fields):
                 return True
         return False
 
-    keys = list(fields)
+    keys = []
+    for key, value in fields.items():
+        if value in ([], 'UNKNOWN', None):
+            continue
+        keys.append(key)
+
     possible_versions = ['1.0', '1.1', '1.2']
 
     # first let's try to see if a field is not part of one of the version
@@ -214,8 +221,9 @@ class Metadata:
             self.read_file(fileobj)
         elif mapping is not None:
             self.update(mapping)
+            self.set_metadata_version()
 
-    def _set_best_version(self):
+    def set_metadata_version(self):
         self._fields['Metadata-Version'] = _best_version(self._fields)
 
     def _write_field(self, file, name, value):
@@ -233,7 +241,6 @@ class Metadata:
             del self._fields[field_name]
         except KeyError:
             raise KeyError(name)
-        self._set_best_version()
 
     def __contains__(self, name):
         return (name in self._fields or
@@ -332,6 +339,7 @@ class Metadata:
                 value = msg[field]
                 if value is not None and value != 'UNKNOWN':
                     self.set(field, value)
+        self.set_metadata_version()
 
     def write(self, filepath):
         """Write the metadata fields to filepath."""
@@ -340,7 +348,8 @@ class Metadata:
 
     def write_file(self, fileobject):
         """Write the PKG-INFO format data to a file object."""
-        self._set_best_version()
+        self.set_metadata_version()
+
         for field in _version2fieldlist(self['Metadata-Version']):
             values = self.get(field)
             if field in _ELEMENTSFIELD:
@@ -367,14 +376,6 @@ class Metadata:
         Keys that don't match a metadata field or that have an empty value are
         dropped.
         """
-        # XXX the code should just use self.set, which does tbe same checks and
-        # conversions already, but that would break packaging.pypi: it uses the
-        # update method, which does not call _set_best_version (which set
-        # does), and thus allows having a Metadata object (as long as you don't
-        # modify or write it) with extra fields from PyPI that are not fields
-        # defined in Metadata PEPs.  to solve it, the best_version system
-        # should be reworked so that it's called only for writing, or in a new
-        # strict mode, or with a new, more lax Metadata subclass in p7g.pypi
         def _set(key, value):
             if key in _ATTR2FIELD and value:
                 self.set(self._convert_name(key), value)
@@ -435,7 +436,6 @@ class Metadata:
                 value = self._remove_line_prefix(value)
 
         self._fields[name] = value
-        self._set_best_version()
 
     def get(self, name, default=_MISSING):
         """Get a metadata field."""
@@ -475,8 +475,10 @@ class Metadata:
         return value
 
     def check(self, strict=False, restructuredtext=False):
-        """Check if the metadata is compliant. If strict is False then raise if
+        """Check if the metadata is compliant. If strict is True then raise if
         no Name or Version are provided"""
+        self.set_metadata_version()
+
         # XXX should check the versions (if the file was loaded)
         missing, warnings = [], []
 
@@ -521,6 +523,7 @@ class Metadata:
         Field names will be converted to use the underscore-lowercase style
         instead of hyphen-mixed case (i.e. home_page instead of Home-page).
         """
+        self.set_metadata_version()
         data = {
             'metadata_version': self['Metadata-Version'],
             'name': self['Name'],