Restore support for EntryPoint access by item. Fixes #348.

importlib_metadata/__init__.py

@@ -125,7 +125,33 @@ def valid(line):
         return line and not line.startswith('#')
 
 
-class EntryPoint:
+class DeprecatedTuple:
+    """
+    Provide subscript item access for backward compatibility.
+
+    >>> recwarn = getfixture('recwarn')
+    >>> ep = EntryPoint(name='name', value='value', group='group')
+    >>> ep[:]
+    ('name', 'value', 'group')
+    >>> ep[0]
+    'name'
+    >>> len(recwarn)
+    1
+    """
+
+    _warn = functools.partial(
+        warnings.warn,
+        "EntryPoint tuple interface is deprecated. Access members by name.",
+        DeprecationWarning,
+        stacklevel=pypy_partial(2),
+    )
+
+    def __getitem__(self, item):
+        self._warn()
+        return self._key()[item]
+
+
+class EntryPoint(DeprecatedTuple):
     """An entry point as defined by Python packaging conventions.
 
     See `the packaging docs on entry points