In egg_info, port use of pkg_resources.EntryPoint to importlib.metadata

2 files changed, 34 insertions, 3 deletions

diff --git a/setuptools/_itertools.py b/setuptools/_itertools.py
new file mode 100644
index 00000000..b8bf6d21
--- /dev/null
+++ b/setuptools/_itertools.py
@@ -0,0 +1,23 @@
+from setuptools.extern.more_itertools import consume  # noqa: F401
+
+
+# copied from jaraco.itertools 6.1
+def ensure_unique(iterable, key=lambda x: x):
+    """
+    Wrap an iterable to raise a ValueError if non-unique values are encountered.
+
+    >>> list(ensure_unique('abc'))
+    ['a', 'b', 'c']
+    >>> consume(ensure_unique('abca'))
+    Traceback (most recent call last):
+    ...
+    ValueError: Duplicate element 'a' encountered.
+    """
+    seen = set()
+    seen_add = seen.add
+    for element in iterable:
+        k = key(element)
+        if k in seen:
+            raise ValueError(f"Duplicate element {element!r} encountered.")
+        seen_add(k)
+        yield element
diff --git a/setuptools/command/egg_info.py b/setuptools/command/egg_info.py
index afab5cd6..2ed58eef 100644
--- a/setuptools/command/egg_info.py
+++ b/setuptools/command/egg_info.py
@@ -16,8 +16,10 @@ import io
 import warnings
 import time
 import collections
+import operator
 
 from .._importlib import metadata
+from .._itertools import ensure_unique
 
 from setuptools import Command
 from setuptools.command.sdist import sdist
@@ -26,7 +28,7 @@ from setuptools.command.setopt import edit_config
 from setuptools.command import bdist_egg
 from pkg_resources import (
     Requirement, safe_name, parse_version,
-    safe_version, yield_lines, EntryPoint, to_filename)
+    safe_version, yield_lines, to_filename)
 import setuptools.unicode_utils as unicode_utils
 from setuptools.glob import glob
 
@@ -721,8 +723,14 @@ def entry_point_definition_to_str(value):
     Given a value of an entry point or series of entry points,
     return each entry point on a single line.
     """
-    parsed = EntryPoint.parse_group('anything', value)
-    return '\n'.join(sorted(map(str, parsed.values())))
+    # normalize to a single sequence of lines
+    lines = yield_lines(value)
+    parsed = metadata.EntryPoints._from_text('[x]\n' + '\n'.join(lines))
+    valid = ensure_unique(parsed, key=operator.attrgetter('name'))
+
+    def ep_to_str(ep):
+        return f'{ep.name} = {ep.value}'
+    return '\n'.join(sorted(map(ep_to_str, valid)))
 
 
 entry_point_definition_to_str.register(str, lambda x: x)