Merge pull request pypa#2635 from cdce8p/refactor-dist

Refactor ``read_pkg_file``

Author: jaraco

setuptools/dist.py

@@ -16,6 +16,8 @@
 from distutils.debug import DEBUG
 from distutils.fancy_getopt import translate_longopt
 import itertools
+import textwrap
+from typing import List, Optional, TYPE_CHECKING
 
 from collections import defaultdict
 from email import message_from_file
@@ -36,6 +38,9 @@
 from setuptools.config import parse_configuration
 import pkg_resources
 
+if TYPE_CHECKING:
+    from email.message import Message
+
 __import__('setuptools.extern.packaging.specifiers')
 __import__('setuptools.extern.packaging.version')
 
@@ -67,53 +72,75 @@ def get_metadata_version(self):
     return mv
 
 
-def read_pkg_file(self, file):
-    """Reads the metadata values from a file object."""
-    msg = message_from_file(file)
+def rfc822_unescape(content: str) -> str:
+    """Reverse RFC-822 escaping by removing leading whitespaces from content."""
+    lines = content.splitlines()
+    if len(lines) == 1:
+        return lines[0].lstrip()
+    return '\n'.join(
+        (lines[0].lstrip(),
+         textwrap.dedent('\n'.join(lines[1:]))))
+
+
+def _read_field_from_msg(msg: "Message", field: str) -> Optional[str]:
+    """Read Message header field."""
+    value = msg[field]
+    if value == 'UNKNOWN':
+        return None
+    return value
+
 
-    def _read_field(name):
-        value = msg[name]
-        if value == 'UNKNOWN':
-            return None
+def _read_field_unescaped_from_msg(msg: "Message", field: str) -> Optional[str]:
+    """Read Message header field and apply rfc822_unescape."""
+    value = _read_field_from_msg(msg, field)
+    if value is None:
         return value
+    return rfc822_unescape(value)
 
-    def _read_list(name):
-        values = msg.get_all(name, None)
-        if values == []:
-            return None
-        return values
+
+def _read_list_from_msg(msg: "Message", field: str) -> Optional[List[str]]:
+    """Read Message header field and return all results as list."""
+    values = msg.get_all(field, None)
+    if values == []:
+        return None
+    return values
+
+
+def read_pkg_file(self, file):
+    """Reads the metadata values from a file object."""
+    msg = message_from_file(file)
 
     self.metadata_version = StrictVersion(msg['metadata-version'])
-    self.name = _read_field('name')
-    self.version = _read_field('version')
-    self.description = _read_field('summary')
+    self.name = _read_field_from_msg(msg, 'name')
+    self.version = _read_field_from_msg(msg, 'version')
+    self.description = _read_field_from_msg(msg, 'summary')
     # we are filling author only.
-    self.author = _read_field('author')
+    self.author = _read_field_from_msg(msg, 'author')
     self.maintainer = None
-    self.author_email = _read_field('author-email')
+    self.author_email = _read_field_from_msg(msg, 'author-email')
     self.maintainer_email = None
-    self.url = _read_field('home-page')
-    self.license = _read_field('license')
+    self.url = _read_field_from_msg(msg, 'home-page')
+    self.license = _read_field_from_msg(msg, 'license')
 
     if 'download-url' in msg:
-        self.download_url = _read_field('download-url')
+        self.download_url = _read_field_from_msg(msg, 'download-url')
     else:
         self.download_url = None
 
-    self.long_description = _read_field('description')
-    self.description = _read_field('summary')
+    self.long_description = _read_field_unescaped_from_msg(msg, 'description')
+    self.description = _read_field_from_msg(msg, 'summary')
 
     if 'keywords' in msg:
-        self.keywords = _read_field('keywords').split(',')
+        self.keywords = _read_field_from_msg(msg, 'keywords').split(',')
 
-    self.platforms = _read_list('platform')
-    self.classifiers = _read_list('classifier')
+    self.platforms = _read_list_from_msg(msg, 'platform')
+    self.classifiers = _read_list_from_msg(msg, 'classifier')
 
     # PEP 314 - these fields only exist in 1.1
     if self.metadata_version == StrictVersion('1.1'):
-        self.requires = _read_list('requires')
-        self.provides = _read_list('provides')
-        self.obsoletes = _read_list('obsoletes')
+        self.requires = _read_list_from_msg(msg, 'requires')
+        self.provides = _read_list_from_msg(msg, 'provides')
+        self.obsoletes = _read_list_from_msg(msg, 'obsoletes')
     else:
         self.requires = None
         self.provides = None

setuptools/tests/test_dist.py

@@ -10,6 +10,8 @@
     check_package_data,
     DistDeprecationWarning,
     check_specifier,
+    rfc822_escape,
+    rfc822_unescape,
 )
 from setuptools import sic
 from setuptools import Distribution
@@ -85,6 +87,9 @@ def __read_test_cases():
         ('Metadata version 1.1: Provides', params(
             provides=['package'],
         )),
+        ('Metadata Version 1.0: Short long description', params(
+            long_description='Short long description',
+        )),
         ('Metadata version 1.1: Obsoletes', params(
             obsoletes=['foo'],
         )),
@@ -162,6 +167,7 @@ def test_read_metadata(name, attrs):
         ('metadata_version', dist_class.get_metadata_version),
         ('provides', dist_class.get_provides),
         ('description', dist_class.get_description),
+        ('long_description', dist_class.get_long_description),
         ('download_url', dist_class.get_download_url),
         ('keywords', dist_class.get_keywords),
         ('platforms', dist_class.get_platforms),
@@ -336,3 +342,37 @@ def test_check_specifier():
     attrs = {'name': 'foo', 'python_requires': ['>=3.0', '!=3.1']}
     with pytest.raises(DistutilsSetupError):
         dist = Distribution(attrs)
+
+
+@pytest.mark.parametrize(
+    'content, result',
+    (
+        pytest.param(
+            "Just a single line",
+            None,
+            id="single_line",
+        ),
+        pytest.param(
+            "Multiline\nText\nwithout\nextra indents\n",
+            None,
+            id="multiline",
+        ),
+        pytest.param(
+            "Multiline\n    With\n\nadditional\n  indentation",
+            None,
+            id="multiline_with_indentation",
+        ),
+        pytest.param(
+            "  Leading whitespace",
+            "Leading whitespace",
+            id="remove_leading_whitespace",
+        ),
+        pytest.param(
+            "  Leading whitespace\nIn\n    Multiline comment",
+            "Leading whitespace\nIn\n    Multiline comment",
+            id="remove_leading_whitespace_multiline",
+        ),
+    )
+)
+def test_rfc822_unescape(content, result):
+    assert (result or content) == rfc822_unescape(rfc822_escape(content))