Issue #19410: Put back in special-casing of '' for

importlib.machinery.FileFinder.

While originally moved to stop special-casing '' as PathFinder farther
up the typical call chain now uses the cwd in the instance of '', it
was deemed an unnecessary risk to breaking subclasses of FileFinder to
take the special-casing out.

Doc/library/importlib.rst

@@ -753,9 +753,6 @@ find and load modules.
 
    .. versionadded:: 3.3
 
-   .. versionchanged:: 3.4
-      The empty string is no longer special-cased to be changed into ``'.'``.
-
    .. attribute:: path
 
       The path the finder will search in.

Doc/whatsnew/3.4.rst

@@ -812,6 +812,3 @@ that may require changes to your code.
   working directory will also now have an absolute path, including when using
   ``-m`` with the interpreter (this does not influence when the path to a file
   is specified on the command-line).
-
-* :class:`importlib.machinery.FileFinder` no longer special-cases the empty string
-  to be changed to ``'.'``.

Lib/importlib/_bootstrap.py

@@ -1375,7 +1375,7 @@ class FileFinder:
             loaders.extend((suffix, loader) for suffix in suffixes)
         self._loaders = loaders
         # Base (directory) path
-        self.path = path
+        self.path = path or '.'
         self._path_mtime = -1
         self._path_cache = set()
         self._relaxed_path_cache = set()

Misc/NEWS

@@ -31,6 +31,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #19410: Undo the special-casing removal of '' for
+  importlib.machinery.FileFinder.
+
 - Issue #19424: Fix the warnings module to accept filename containing surrogate
   characters.