Remove egg and wininst support

changelog/1195.removal.txt

@@ -0,0 +1,2 @@
+- Remove support for ``egg`` and ``wininst` distribution types. These are not
+  accepted by PyPI and not produced by any modern build-backeds.

docs/internal/twine.rst

@@ -15,4 +15,3 @@ twine package
    twine.settings
    twine.utils
    twine.wheel
-   twine.wininst

tests/test_package.py

@@ -463,12 +463,14 @@ def test_malformed_from_file(monkeypatch):
     assert "Invalid distribution file" in err.value.args[0]
 
 
-def test_package_from_egg():
-    filename = "tests/fixtures/twine-3.3.0-py3.9.egg"
-    package_file.PackageFile.from_filename(filename, comment=None)
-
-
 def test_package_from_sdist():
     filename = "tests/fixtures/twine-1.5.0.tar.gz"
     p = package_file.PackageFile.from_filename(filename, comment=None)
     assert p.python_version == "source"
+
+
+def test_package_from_unrecognized_file_error():
+    filename = "twine/package.py"
+    with pytest.raises(exceptions.InvalidDistribution) as err:
+        package_file.PackageFile.from_filename(filename, comment=None)
+    assert "Unknown distribution format" in err.value.args[0]

twine/package.py

@@ -44,19 +44,14 @@
 
 from twine import exceptions
 from twine import wheel
-from twine import wininst
 
 DIST_TYPES = {
-    "bdist_wheel": wheel.Wheel,
-    "bdist_wininst": wininst.WinInst,
-    "bdist_egg": pkginfo.BDist,
+    "wheel": wheel.Wheel,
     "sdist": pkginfo.SDist,
 }
 
 DIST_EXTENSIONS = {
-    ".whl": "bdist_wheel",
-    ".exe": "bdist_wininst",
-    ".egg": "bdist_egg",
+    ".whl": "wheel",
     ".tar.bz2": "sdist",
     ".tar.gz": "sdist",
     ".zip": "sdist",
@@ -157,13 +152,8 @@ def from_filename(cls, filename: str, comment: Optional[str]) -> "PackageFile":
                 )
             raise exceptions.InvalidDistribution(msg)
 
-        if dtype == "bdist_egg":
-            (dist,) = importlib_metadata.Distribution.discover(path=[filename])
-            py_version = dist.metadata["Version"]
-        elif dtype == "bdist_wheel":
+        if dtype == "wheel":
             py_version = cast(wheel.Wheel, meta).py_version
-        elif dtype == "bdist_wininst":
-            py_version = cast(wininst.WinInst, meta).py_version
         elif dtype == "sdist":
             py_version = "source"
         else: