1 files changed, 39 insertions, 7 deletions

diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 7d0b1d8aef..735ad9d63e 100644
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -2614,18 +2614,50 @@ def browse(port=0, *, open_browser=True, hostname='localhost'):
 def ispath(x):
     return isinstance(x, str) and x.find(os.sep) >= 0
 
+def _get_revised_path(given_path, argv0):
+    """Ensures current directory is on returned path, and argv0 directory is not
+
+    Exception: argv0 dir is left alone if it's also pydoc's directory.
+
+    Returns a new path entry list, or None if no adjustment is needed.
+    """
+    # Scripts may get the current directory in their path by default if they're
+    # run with the -m switch, or directly from the current directory.
+    # The interactive prompt also allows imports from the current directory.
+
+    # Accordingly, if the current directory is already present, don't make
+    # any changes to the given_path
+    if '' in given_path or os.curdir in given_path or os.getcwd() in given_path:
+        return None
+
+    # Otherwise, add the current directory to the given path, and remove the
+    # script directory (as long as the latter isn't also pydoc's directory.
+    stdlib_dir = os.path.dirname(__file__)
+    script_dir = os.path.dirname(argv0)
+    revised_path = given_path.copy()
+    if script_dir in given_path and not os.path.samefile(script_dir, stdlib_dir):
+        revised_path.remove(script_dir)
+    revised_path.insert(0, os.getcwd())
+    return revised_path
+
+
+# Note: the tests only cover _get_revised_path, not _adjust_cli_path itself
+def _adjust_cli_sys_path():
+    """Ensures current directory is on sys.path, and __main__ directory is not
+
+    Exception: __main__ dir is left alone if it's also pydoc's directory.
+    """
+    revised_path = _get_revised_path(sys.path, sys.argv[0])
+    if revised_path is not None:
+        sys.path[:] = revised_path
+
+
 def cli():
     """Command-line interface (looks at sys.argv to decide what to do)."""
     import getopt
     class BadUsage(Exception): pass
 
-    # Scripts don't get the current directory in their path by default
-    # unless they are run with the '-m' switch
-    if '' not in sys.path:
-        scriptdir = os.path.dirname(sys.argv[0])
-        if scriptdir in sys.path:
-            sys.path.remove(scriptdir)
-        sys.path.insert(0, '.')
+    _adjust_cli_sys_path()
 
     try:
         opts, args = getopt.getopt(sys.argv[1:], 'bk:n:p:w')