cmd2 now uses pyreadline3 when running any version of Python on Windows

Author: kmvanbrunt

CHANGELOG.md

@@ -5,6 +5,7 @@
 * Enhancements
   * Added broader exception handling when enabling clipboard functionality via `pyperclip`.
   * Added `PassThroughException` to `__init__.py` imports.
+  * cmd2 now uses pyreadline3 when running any version of Python on Windows
 * Deletions (potentially breaking changes)
   * Deleted `cmd2.fg` and `cmd2.bg` which were deprecated in 2.3.0. Use `cmd2.Fg` and `cmd2.Bg` instead.
 

Pipfile

@@ -22,8 +22,7 @@ ipython = "*"
 isort = "*"
 mock = {version = "*",markers = "python_version < '3.6'"}
 mypy = "*"
-pyreadline = {version = "*",sys_platform = "== 'win32'",markers = "python_version < '3.8'"}
-pyreadline3 = {version = "*",sys_platform = "== 'win32'",markers = "python_version >= '3.8'"}
+pyreadline3 = {version = ">=3.4",sys_platform = "== 'win32'"}
 pytest = "*"
 pytest-cov = "*"
 pytest-mock = "*"

cmd2/cmd2.py

@@ -155,7 +155,7 @@
 
     if rl_type == RlType.PYREADLINE:
 
-        # Save the original pyreadline display completion function since we need to override it and restore it
+        # Save the original pyreadline3 display completion function since we need to override it and restore it
         # noinspection PyProtectedMember,PyUnresolvedReferences
         orig_pyreadline_display = readline.rl.mode._display_completions
 
@@ -1747,7 +1747,7 @@ def _pad_matches_to_display(matches_to_display: List[str]) -> Tuple[List[str], i
             padding = 2 * ' '
 
         elif rl_type == RlType.PYREADLINE:
-            # Add 3 to the padding of 1 that pyreadline uses for a total of 4.
+            # Add 3 to the padding of 1 that pyreadline3 uses for a total of 4.
             padding = 3 * ' '
 
         else:
@@ -1820,7 +1820,7 @@ def _display_matches_gnu_readline(
             rl_force_redisplay()
 
     def _display_matches_pyreadline(self, matches: List[str]) -> None:  # pragma: no cover
-        """Prints a match list using pyreadline's _display_completions()
+        """Prints a match list using pyreadline3's _display_completions()
 
         :param matches: the tab completion matches to display
         """
@@ -1841,7 +1841,7 @@ def _display_matches_pyreadline(self, matches: List[str]) -> None:  # pragma: no
                 # Redraw the prompt and input lines
                 rl_force_redisplay()
 
-            # Otherwise use pyreadline's formatter
+            # Otherwise use pyreadline3's formatter
             else:
                 # Check if we should show display_matches
                 if self.display_matches:

cmd2/rl_utils.py

@@ -26,13 +26,12 @@
 # The workaround for Python environments using libedit is to install the gnureadline Python library.
 #########################################################################################################################
 
-# Prefer statically linked gnureadline if available due to issues with libedit
+# Prefer statically linked gnureadline if installed due to compatibility issues with libedit
 try:
     # noinspection PyPackageRequirements
     import gnureadline as readline  # type: ignore[import]
 except ImportError:
-    # Try to import readline, but allow failure for convenience in Windows unit testing.
-    # Note: If this actually fails, you should install gnureadline on Linux/Mac or pyreadline on Windows.
+    # Note: If this actually fails, you should install gnureadline on Linux/Mac or pyreadline3 on Windows.
     try:
         # noinspection PyUnresolvedReferences
         import readline  # type: ignore[no-redef]
@@ -57,8 +56,8 @@ class RlType(Enum):
 # Explanation for why Readline wasn't loaded
 _rl_warn_reason = ''
 
-# The order of this check matters since importing pyreadline/pyreadline3 will also show readline in the modules list
-if 'pyreadline' in sys.modules or 'pyreadline3' in sys.modules:
+# The order of this check matters since importing pyreadline3 will also show readline in the modules list
+if 'pyreadline3' in sys.modules:
     rl_type = RlType.PYREADLINE
 
     import atexit
@@ -109,7 +108,7 @@ def enable_win_vt100(handle: HANDLE) -> bool:
         vt100_support = vt100_stdout_support and vt100_stderr_support
 
     ############################################################################################################
-    # pyreadline is incomplete in terms of the Python readline API. Add the missing functions we need.
+    # pyreadline3 is incomplete in terms of the Python readline API. Add the missing functions we need.
     ############################################################################################################
     # readline.redisplay()
     try:
@@ -125,7 +124,7 @@ def enable_win_vt100(handle: HANDLE) -> bool:
         # noinspection PyProtectedMember,PyUnresolvedReferences
         def pyreadline_remove_history_item(pos: int) -> None:
             """
-            An implementation of remove_history_item() for pyreadline
+            An implementation of remove_history_item() for pyreadline3
             :param pos: The 0-based position in history to remove
             """
             # Save of the current location of the history cursor
@@ -162,7 +161,7 @@ def pyreadline_remove_history_item(pos: int) -> None:
     if not _rl_warn_reason:
         _rl_warn_reason = (
             "no supported version of readline was found. To resolve this, install\n"
-            "pyreadline on Windows or gnureadline on Linux/Mac."
+            "pyreadline3 on Windows or gnureadline on Linux/Mac."
         )
     rl_warning = "Readline features including tab completion have been disabled because\n" + _rl_warn_reason + '\n\n'
 else:

docs/overview/integrating.rst

@@ -26,13 +26,10 @@ Windows Considerations
 
 If you would like to use :ref:`features/completion:Completion`, and you want
 your application to run on Windows, you will need to ensure you install the
-``pyreadline3`` or ``pyreadline`` package. Make sure to include the following
+``pyreadline3`` package. Make sure to include the following
 in your ``setup.py``::
 
   install_requires=[
     'cmd2>=1,<2',
-    ":sys_platform=='win32'": [
-        "pyreadline ; python_version<'3.8'",
-        "pyreadline3 ; python_version>='3.8'",  # pyreadline3 is a drop-in replacement for Python 3.8 and above
-    ],
+    ":sys_platform=='win32'": ['pyreadline3'],
   ]

setup.py

@@ -51,9 +51,8 @@
 ]
 
 EXTRAS_REQUIRE = {
-    # Windows also requires pyreadline or the replacement, pyreadline3, to ensure tab completion works
-    ":sys_platform=='win32' and python_version<'3.8'": ["pyreadline"],
-    ":sys_platform=='win32' and python_version>='3.8'": ["pyreadline3"],
+    # Windows also requires pyreadline3 to ensure tab completion works
+    ":sys_platform=='win32'": ['pyreadline3'],
     # Extra dependencies for running unit tests
     'test': [
         "gnureadline; sys_platform=='darwin'",  # include gnureadline on macOS to ensure it is available in nox env

tests/conftest.py

@@ -21,22 +21,13 @@
 )
 
 import cmd2
+from cmd2.rl_utils import (
+    readline,
+)
 from cmd2.utils import (
     StdSim,
 )
 
-# Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit)
-try:
-    import gnureadline as readline
-except ImportError:
-    # Try to import readline, but allow failure for convenience in Windows unit testing
-    # Note: If this actually fails, you should install readline on Linux or Mac or pyreadline on Windows
-    try:
-        # noinspection PyUnresolvedReferences
-        import readline
-    except ImportError:
-        pass
-
 
 def verify_help_text(
     cmd2_app: cmd2.Cmd, help_output: Union[str, List[str]], verbose_strings: Optional[List[str]] = None

tests/test_argparse.py

@@ -16,18 +16,6 @@
     run_cmd,
 )
 
-# Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit)
-try:
-    import gnureadline as readline
-except ImportError:
-    # Try to import readline, but allow failure for convenience in Windows unit testing
-    # Note: If this actually fails, you should install readline on Linux or Mac or pyreadline on Windows
-    try:
-        # noinspection PyUnresolvedReferences
-        import readline
-    except ImportError:
-        pass
-
 
 class ArgparseApp(cmd2.Cmd):
     def __init__(self):

tests_isolated/test_commandset/conftest.py

@@ -24,22 +24,13 @@
 )
 
 import cmd2
+from cmd2.rl_utils import (
+    readline,
+)
 from cmd2.utils import (
     StdSim,
 )
 
-# Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit)
-try:
-    import gnureadline as readline
-except ImportError:
-    # Try to import readline, but allow failure for convenience in Windows unit testing
-    # Note: If this actually fails, you should install readline on Linux or Mac or pyreadline on Windows
-    try:
-        # noinspection PyUnresolvedReferences
-        import readline
-    except ImportError:
-        pass
-
 
 def verify_help_text(
     cmd2_app: cmd2.Cmd, help_output: Union[str, List[str]], verbose_strings: Optional[List[str]] = None