Disallow files for license inputs

The ability to handle files was originally added and documented based on
a misunderstanding of what the `license` field should include. The field
should be the name of the license, not the full text.

It is likely that anyone actually using this was outputing malformed
PKG-INFO files, because most license files contain newlines.

See GH issue #1551

1 files changed, 20 insertions, 2 deletions

diff --git a/setuptools/config.py b/setuptools/config.py
index d1ac6734..3a6da20f 100644
--- a/setuptools/config.py
+++ b/setuptools/config.py
@@ -247,6 +247,24 @@ class ConfigHandler:
         return value in ('1', 'true', 'yes')
 
     @classmethod
+    def _exclude_files_parser(cls, key):
+        """Returns a parser function to make sure field inputs
+        are not files.
+
+        Parses a value after getting the key so error messages are
+        more informative.
+
+        :param key:
+        :rtype: callable
+        """
+        def parser(value):
+            exclude_directive = 'file:'
+            if value.startswith(exclude_directive):
+                raise ValueError('Only strings are accepted for the {0} field, files are not accepted'.format(key))
+            return value
+        return parser
+
+    @classmethod
     def _parse_file(cls, value):
         """Represents value as a string, allowing including text
         from nearest files using `file:` directive.
@@ -255,7 +273,6 @@ class ConfigHandler:
         directory with setup.py.
 
         Examples:
-            file: LICENSE
             file: README.rst, CHANGELOG.md, src/file.txt
 
         :param str value:
@@ -449,6 +466,7 @@ class ConfigMetadataHandler(ConfigHandler):
         parse_list = self._parse_list
         parse_file = self._parse_file
         parse_dict = self._parse_dict
+        exclude_files_parser = self._exclude_files_parser
 
         return {
             'platforms': parse_list,
@@ -460,7 +478,7 @@ class ConfigMetadataHandler(ConfigHandler):
                 DeprecationWarning),
             'obsoletes': parse_list,
             'classifiers': self._get_parser_compound(parse_file, parse_list),
-            'license': parse_file,
+            'license': exclude_files_parser('license'),
             'description': parse_file,
             'long_description': parse_file,
             'version': self._parse_version,