drop support for Python 2.x as it is very much EOL

A follow-up to b96a5ad562deffa697d966c29546650aae645f48 where we stopped
having CI run tests on Python 2.x. This actually drops the few remaining
Python 2.x compatibility bits as Python 2.x has EOL'd a long time ago.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

12 files changed, 85 insertions, 252 deletions

diff --git a/README.rst b/README.rst
index a3469f5..8d31730 100644
--- a/README.rst
+++ b/README.rst
@@ -33,7 +33,7 @@ Overview
 
 Kconfiglib is a `Kconfig
 <https://github.com/torvalds/linux/blob/master/Documentation/kbuild/kconfig-language.rst>`__
-implementation in Python 2/3. It started out as a helper library, but now has a
+implementation in Python 3. It started out as a helper library, but now has a
 enough functionality to also work well as a standalone Kconfig implementation
 (including `terminal and GUI menuconfig interfaces <Menuconfig interfaces_>`_
 and `Kconfig extensions`_).
@@ -121,9 +121,7 @@ available in the C tools.
 the configuration and (optionally) information that can be used to rebuild only
 files that reference Kconfig symbols that have changed value.
 
-Starting with Kconfiglib version 12.2.0, all utilities are compatible with both
-Python 2 and Python 3. Previously, ``menuconfig.py`` only ran under Python 3
-(i.e., it's now more backwards compatible than before).
+All utilities run under Python 3.
 
 **Note:** If you install Kconfiglib with ``pip``'s ``--user`` flag, make sure
 that your ``PATH`` includes the directory where the executables end up. You can
@@ -164,18 +162,13 @@ Installation for the Linux kernel
 
 See the module docstring at the top of `kconfiglib.py <https://github.com/zephyrproject-rtos/Kconfiglib/blob/master/kconfiglib.py>`_.
 
-Python version compatibility (2.7/3.2+)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Python version compatibility
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Kconfiglib and all utilities run under both Python 2.7 and Python 3.2 and
-later. The code mostly uses basic Python features and has no third-party
-dependencies, so keeping it backwards-compatible is pretty low effort.
+Kconfiglib and all utilities run under Python 3.9 and later. The code mostly
+uses basic Python features and has no third-party dependencies.
 
-The 3.2 requirement comes from ``argparse``. ``format()`` with unnumbered
-``{}`` is used as well.
-
-A recent Python 3 version is recommended if you have a choice, as it'll give
-you better Unicode handling.
+A recent Python 3 version is recommended for better Unicode handling.
 
 Getting started
 ---------------
@@ -502,9 +495,9 @@ Other features
 
 - **Windows support**
 
-  Nothing Linux-specific is used. Universal newlines mode is used for both
-  Python 2 and Python 3.
-  
+  Nothing Linux-specific is used. Universal newlines mode is used for
+  interoperability between Linux and Windows.
+
   The `Zephyr <https://www.zephyrproject.org/>`_ project uses Kconfiglib to
   generate ``.config`` files and C headers on Linux as well as Windows.
 
@@ -562,16 +555,15 @@ Three configuration interfaces are currently available:
   the terminal menuconfig. Only this mode distinguishes between symbols defined
   with ``config`` and symbols defined with ``menuconfig``.
 
-  ``guiconfig.py`` has been tested on X11, Windows, and macOS, and is
-  compatible with both Python 2 and Python 3.
+  ``guiconfig.py`` has been tested on X11, Windows, and macOS.
 
   Despite being part of the Python standard library, ``tkinter`` often isn't
   included by default in Python installations on Linux. These commands will
   install it on a few different distributions:
 
-  - Ubuntu: ``sudo apt install python-tk``/``sudo apt install python3-tk``
+  - Ubuntu: ``sudo apt install python3-tk``
 
-  - Fedora: ``dnf install python2-tkinter``/``dnf install python3-tkinter``
+  - Fedora: ``dnf install python3-tkinter``
 
   - Arch: ``sudo pacman -S tk``
 
@@ -591,10 +583,6 @@ Three configuration interfaces are currently available:
   I did my best with the images, but some are definitely only art adjacent.
   Touch-ups are welcome. :)
 
-- `pymenuconfig <https://github.com/RomaVis/pymenuconfig>`_, built by `RomaVis
-  <https://github.com/RomaVis>`_, is an older portable Python 2/3 TkInter
-  menuconfig implementation.
-
   Screenshot below:
 
   .. image:: https://raw.githubusercontent.com/RomaVis/pymenuconfig/master/screenshot.PNG
@@ -784,7 +772,7 @@ configurations generated by the C tools, for a number of cases. See
 for the available options.
 
 The `tests/reltest <https://github.com/zephyrproject-rtos/Kconfiglib/blob/master/tests/reltest>`_ script runs the test suite
-and all the example scripts for both Python 2 and Python 3, verifying that everything works.
+and all the example scripts, verifying that everything works.
 
 Rarely, the output from the C tools is changed slightly (most recently due to a
 `change <https://www.spinics.net/lists/linux-kbuild/msg17074.html>`_ I added).
diff --git a/examples/menuconfig_example.py b/examples/menuconfig_example.py
index 606f756..9221e4c 100755
--- a/examples/menuconfig_example.py
+++ b/examples/menuconfig_example.py
@@ -130,11 +130,6 @@ from kconfiglib import Kconfig, \
                        TRI_TO_STR
 
 
-# Python 2/3 compatibility hack
-if sys.version_info[0] < 3:
-    input = raw_input
-
-
 def indent_print(s, indent):
     print(indent*" " + s)
 
diff --git a/genconfig.py b/genconfig.py
index 62f065b..aa0b472 100755
--- a/genconfig.py
+++ b/genconfig.py
@@ -131,24 +131,15 @@ only supported for backwards compatibility).
         kconf.sync_deps(args.sync_deps)
 
     if args.file_list is not None:
-        with _open_write(args.file_list) as f:
+        with open(args.file_list, "w", encoding="utf-8") as f:
             for path in kconf.kconfig_filenames:
                 f.write(path + "\n")
 
     if args.env_list is not None:
-        with _open_write(args.env_list) as f:
+        with open(args.env_list, "w", encoding="utf-8") as f:
             for env_var in kconf.env_vars:
                 f.write("{}={}\n".format(env_var, os.environ[env_var]))
 
 
-def _open_write(path):
-    # Python 2/3 compatibility. io.open() is available on both, but makes
-    # write() expect 'unicode' strings on Python 2.
-
-    if sys.version_info[0] < 3:
-        return open(path, "w")
-    return open(path, "w", encoding="utf-8")
-
-
 if __name__ == "__main__":
     main()
diff --git a/guiconfig.py b/guiconfig.py
index 21f034e..da3b486 100755
--- a/guiconfig.py
+++ b/guiconfig.py
@@ -9,7 +9,7 @@ Overview
 
 A Tkinter-based menuconfig implementation, based around a treeview control and
 a help display. The interface should feel familiar to people used to qconf
-('make xconfig'). Compatible with both Python 2 and Python 3.
+('make xconfig').
 
 The display can be toggled between showing the full tree and showing just a
 single menu (like menuconfig.py). Only single-menu mode distinguishes between
@@ -55,23 +55,11 @@ $srctree is supported through Kconfiglib.
 import errno
 import os
 import re
-import sys
-
-_PY2 = sys.version_info[0] < 3
-
-if _PY2:
-    # Python 2
-    from Tkinter import *
-    import ttk
-    import tkFont as font
-    import tkFileDialog as filedialog
-    import tkMessageBox as messagebox
-else:
-    # Python 3
-    from tkinter import *
-    import tkinter.ttk as ttk
-    import tkinter.font as font
-    from tkinter import filedialog, messagebox
+
+from tkinter import *
+import tkinter.ttk as ttk
+import tkinter.font as font
+from tkinter import filedialog, messagebox
 
 from kconfiglib import Symbol, Choice, MENU, COMMENT, MenuNode, \
                        BOOL, TRISTATE, STRING, INT, HEX, \
@@ -438,8 +426,7 @@ def _init_misc_ui():
     _dark_mode = _detect_system_dark_mode()
 
     _root.title(_kconf.mainmenu_text)
-    # iconphoto() isn't available in Python 2's Tkinter
-    _root.tk.call("wm", "iconphoto", _root._w, "-default", _icon_img)
+    _root.iconphoto(True, _icon_img)
     # Reducing the width of the window to 1 pixel makes it move around, at
     # least on GNOME. Prevent weird stuff like that.
     _root.minsize(128, 128)
@@ -616,9 +603,7 @@ def _create_kconfig_tree_and_desc(parent):
             desc["state"] = "disabled"
             return
 
-        # Text.replace() is not available in Python 2's Tkinter
-        desc.delete("1.0", "end")
-        desc.insert("end", _info_str(_id_to_node[sel[0]]))
+        desc.replace("1.0", "end", _info_str(_id_to_node[sel[0]]))
 
         desc["state"] = "disabled"
 
@@ -1230,11 +1215,6 @@ def _change_node(node, parent):
     if sc.type in (INT, HEX, STRING):
         s = _set_val_dialog(node, parent)
 
-        # Tkinter can return 'unicode' strings on Python 2, which Kconfiglib
-        # can't deal with. UTF-8-encode the string to work around it.
-        if _PY2 and isinstance(s, unicode):
-            s = s.encode("utf-8", "ignore")
-
         if s is not None:
             _set_val(sc, s)
 
@@ -1286,9 +1266,10 @@ def _set_val_dialog(node, parent):
     # Pops up a dialog for setting the value of the string/int/hex
     # symbol at node 'node'. 'parent' is the parent window.
 
+    _entry_res = None
+
     def ok(_=None):
-        # No 'nonlocal' in Python 2
-        global _entry_res
+        nonlocal _entry_res
 
         s = entry.get()
         if sym.type == HEX and not s.startswith(("0x", "0X")):
@@ -1299,7 +1280,7 @@ def _set_val_dialog(node, parent):
             dialog.destroy()
 
     def cancel(_=None):
-        global _entry_res
+        nonlocal _entry_res
         _entry_res = None
         dialog.destroy()
 
diff --git a/kconfiglib.py b/kconfiglib.py
index ce40eb7..2bbc517 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -5,7 +5,7 @@
 Overview
 ========
 
-Kconfiglib is a Python 2/3 library for scripting and extracting information
+Kconfiglib is a Python 3 library for scripting and extracting information
 from Kconfig (https://www.kernel.org/doc/Documentation/kbuild/kconfig-language.txt)
 configuration systems.
 
@@ -52,17 +52,14 @@ sections.
 make kmenuconfig
 ----------------
 
-This target runs the curses menuconfig interface with Python 3. As of
-Kconfiglib 12.2.0, both Python 2 and Python 3 are supported (previously, only
-Python 3 was supported, so this was a backport).
+This target runs the curses menuconfig interface with Python 3.
 
 
 make guiconfig
 --------------
 
-This target runs the Tkinter menuconfig interface. Both Python 2 and Python 3
-are supported. To change the Python interpreter used, pass
-PYTHONCMD=<executable> to 'make'. The default is 'python'.
+This target runs the Tkinter menuconfig interface. To change the Python
+interpreter used, pass PYTHONCMD=<executable> to 'make'. The default is 'python'.
 
 
 make [ARCH=<arch>] iscriptconfig
@@ -878,11 +875,8 @@ class Kconfig(object):
 
         Raises KconfigError on syntax/semantic errors, and OSError or (possibly
         a subclass of) IOError on IO errors ('errno', 'strerror', and
-        'filename' are available). Note that IOError is an alias for OSError on
-        Python 3, so it's enough to catch OSError there. If you need Python 2/3
-        compatibility, it's easiest to catch EnvironmentError, which is a
-        common base class of OSError/IOError on Python 2 and an alias for
-        OSError on Python 3.
+        'filename' are available). Note that IOError is an alias for OSError in
+        Python 3, so it's enough to catch OSError.
 
         filename (default: "Kconfig"):
           The Kconfig file to load. For the Linux kernel, you'll want "Kconfig"
@@ -925,11 +919,6 @@ class Kconfig(object):
           The "utf-8" default avoids exceptions on systems that are configured
           to use the C locale, which implies an ASCII encoding.
 
-          This parameter has no effect on Python 2, due to implementation
-          issues (regular strings turning into Unicode strings, which are
-          distinct in Python 2). Python 2 doesn't decode regular strings
-          anyway.
-
           Related PEP: https://www.python.org/dev/peps/pep-0538/
 
         suppress_traceback (default: False):
@@ -2118,18 +2107,12 @@ class Kconfig(object):
             try:
                 return self._open(join(self.srctree, filename), "r")
             except EnvironmentError as e2:
-                # This is needed for Python 3, because e2 is deleted after
-                # the try block:
-                #
-                # https://docs.python.org/3/reference/compound_stmts.html#the-try-statement
-                e = e2
-
-            raise _KconfigIOError(
-                e, "Could not open '{}' ({}: {}). Check that the $srctree "
-                   "environment variable ({}) is set correctly."
-                   .format(filename, errno.errorcode[e.errno], e.strerror,
-                           "set to '{}'".format(self.srctree) if self.srctree
-                               else "unset or blank"))
+                raise _KconfigIOError(
+                    e2, "Could not open '{}' ({}: {}). Check that the $srctree "
+                    "environment variable ({}) is set correctly."
+                    .format(filename, errno.errorcode[e.errno], e.strerror,
+                            "set to '{}'".format(self.srctree) if self.srctree
+                                else "unset or blank"))
 
     def _enter_file(self, filename):
         # Jumps to the beginning of a sourced Kconfig file, saving the previous
@@ -3895,41 +3878,8 @@ class Kconfig(object):
         self._parse_error("extra tokens at end of line")
 
     def _open(self, filename, mode):
-        # open() wrapper:
-        #
-        # - Enable universal newlines mode on Python 2 to ease
-        #   interoperability between Linux and Windows. It's already the
-        #   default on Python 3.
-        #
-        #   The "U" flag would currently work for both Python 2 and 3, but it's
-        #   deprecated on Python 3, so play it future-safe.
-        #
-        #   io.open() defaults to universal newlines on Python 2 (and is an
-        #   alias for open() on Python 3), but it returns 'unicode' strings and
-        #   slows things down:
-        #
-        #     Parsing x86 Kconfigs on Python 2
-        #
-        #     with open(..., "rU"):
-        #
-        #       real  0m0.930s
-        #       user  0m0.905s
-        #       sys   0m0.025s
-        #
-        #     with io.open():
-        #
-        #       real  0m1.069s
-        #       user  0m1.040s
-        #       sys   0m0.029s
-        #
-        #   There's no appreciable performance difference between "r" and
-        #   "rU" for parsing performance on Python 2.
-        #
-        # - For Python 3, force the encoding. Forcing the encoding on Python 2
-        #   turns strings into Unicode strings, which gets messy. Python 2
-        #   doesn't decode regular strings anyway.
-        return open(filename, "rU" if mode == "r" else mode) if _IS_PY2 else \
-               open(filename, mode, encoding=self._encoding)
+        # open() wrapper that forces the encoding
+        return open(filename, mode, encoding=self._encoding)
 
     def _check_undef_syms(self):
         # Prints warnings for all references to undefined symbols within the
@@ -3958,7 +3908,7 @@ class Kconfig(object):
 
             return True
 
-        for sym in (self.syms.viewvalues if _IS_PY2 else self.syms.values)():
+        for sym in self.syms.values():
             # - sym.nodes empty means the symbol is undefined (has no
             #   definition locations)
             #
@@ -6513,16 +6463,9 @@ def _save_old(path):
     if islink(path):
         # Preserve symlinks
         copy_fn = copy
-    elif hasattr(os, "replace"):
-        # Python 3 (3.3+) only. Best choice when available, because it
-        # removes <filename>.old on both *nix and Windows.
-        copy_fn = os.replace
-    elif os.name == "posix":
-        # Removes <filename>.old on POSIX systems
-        copy_fn = os.rename
     else:
-        # Fall back on copying
-        copy_fn = copy
+        # atomic replace of <filename>.old
+        copy_fn = os.replace
 
     try:
         copy_fn(path, path + ".old")
@@ -6894,30 +6837,21 @@ def _error_if_fn(kconf, _, cond, msg):
 def _shell_fn(kconf, _, command):
     import subprocess  # Only import as needed, to save some startup time
 
-    stdout, stderr = subprocess.Popen(
-        command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE
-    ).communicate()
-
-    if not _IS_PY2:
-        try:
-            stdout = stdout.decode(kconf._encoding)
-            stderr = stderr.decode(kconf._encoding)
-        except UnicodeDecodeError as e:
-            _decoding_error(e, kconf.filename, kconf.linenr)
+    result = subprocess.run(
+        command,
+        shell=True,
+        capture_output=True,
+        text=True,
+        encoding=kconf._encoding
+    )
 
-    if stderr:
+    if result.stderr:
         kconf._warn("'{}' wrote to stderr: {}".format(
-                        command, "\n".join(stderr.splitlines())),
+                        command, "\n".join(result.stderr.splitlines())),
                     kconf.loc)
 
-    # Universal newlines with splitlines() (to prevent e.g. stray \r's in
-    # command output on Windows), trailing newline removal, and
-    # newline-to-space conversion.
-    #
-    # On Python 3 versions before 3.6, it's not possible to specify the
-    # encoding when passing universal_newlines=True to Popen() (the 'encoding'
-    # parameter was added in 3.6), so we do this manual version instead.
-    return "\n".join(stdout.splitlines()).rstrip("\n").replace("\n", " ")
+    # Trailing newline removal, and newline-to-space conversion.
+    return result.stdout.rstrip("\n").replace("\n", " ")
 
 #
 # Global constants
@@ -6940,9 +6874,6 @@ STR_TO_TRI = {
 # Symbol will do. We test this with 'is'.
 _NO_CACHED_SELECTION = 0
 
-# Are we running on Python 2?
-_IS_PY2 = sys.version_info[0] < 3
-
 try:
     _UNAME_RELEASE = os.uname()[2]
 except AttributeError:
@@ -7231,15 +7162,14 @@ KIND_TO_STR = {
 # Helper functions for getting compiled regular expressions, with the needed
 # matching function returned directly as a small optimization.
 #
-# Use ASCII regex matching on Python 3. It's already the default on Python 2.
-
+# Use ASCII regex matching on Python 3.
 
 def _re_match(regex):
-    return re.compile(regex, 0 if _IS_PY2 else re.ASCII).match
+    return re.compile(regex, re.ASCII).match
 
 
 def _re_search(regex):
-    return re.compile(regex, 0 if _IS_PY2 else re.ASCII).search
+    return re.compile(regex, re.ASCII).search
 
 
 # Various regular expressions used during parsing
diff --git a/listnewconfig.py b/listnewconfig.py
index 8276de1..18209ce 100755
--- a/listnewconfig.py
+++ b/listnewconfig.py
@@ -15,6 +15,7 @@ from __future__ import print_function
 
 import argparse
 import sys
+import textwrap
 
 from kconfiglib import Kconfig, BOOL, TRISTATE, INT, HEX, STRING, TRI_TO_STR
 
@@ -65,10 +66,8 @@ def main():
             if args.show_help:
                 for node in sym.nodes:
                     if node.help is not None:
-                        # Indent by two spaces. textwrap.indent() is not
-                        # available in Python 2 (it's 3.3+).
-                        print("\n".join("  " + line
-                                        for line in node.help.split("\n")))
+                        # Indent by two spaces.
+                        print(textwrap.indent(node.help, "  "))
                         break
 
 
diff --git a/menuconfig.py b/menuconfig.py
index 178fbc1..01ac624 100755
--- a/menuconfig.py
+++ b/menuconfig.py
@@ -7,7 +7,7 @@
 Overview
 ========
 
-A curses-based Python 2/3 menuconfig implementation. The interface should feel
+A curses-based Python 3 menuconfig implementation. The interface should feel
 familiar to people used to mconf ('make menuconfig').
 
 Supports the same keys as mconf, and also supports a set of keybindings
@@ -989,12 +989,7 @@ def _init():
     # Looking for this in addition to KEY_BACKSPACE (which is unreliable) makes
     # backspace work with TERM=vt100. That makes it likely to work in sane
     # environments.
-    _ERASE_CHAR = curses.erasechar()
-    if sys.version_info[0] >= 3:
-        # erasechar() returns a one-byte bytes object on Python 3. This sets
-        # _ERASE_CHAR to a blank string if it can't be decoded, which should be
-        # harmless.
-        _ERASE_CHAR = _ERASE_CHAR.decode("utf-8", "ignore")
+    _ERASE_CHAR = curses.erasechar().decode("utf-8", "ignore")
 
     _init_styles()
 
@@ -2141,11 +2136,7 @@ def _jump_to_dialog():
 
             except re.error as e:
                 # Bad regex. Remember the error message so we can show it.
-                bad_re = "Bad regular expression"
-                # re.error.msg was added in Python 3.5
-                if hasattr(e, "msg"):
-                    bad_re += ": " + e.msg
-
+                bad_re = f"Bad regular expression: {e.msg}"
                 matches = []
 
             # Reset scroll and jump to the top of the list of matches
@@ -2648,7 +2639,7 @@ def _help_info(sc):
 
     for node in sc.nodes:
         if node.help is not None:
-            s += "Help:\n\n{}\n\n".format(_indent(node.help, 2))
+            s += "Help:\n\n{}\n\n".format(textwrap.indent(node.help, "  "))
 
     return s
 
@@ -2790,7 +2781,7 @@ def _kconfig_def_info(item):
              .format(node.filename, node.linenr,
                      _include_path_info(node),
                      _menu_path_info(node),
-                     _indent(node.custom_str(_name_and_val_str), 2))
+                     textwrap.indent(node.custom_str(_name_and_val_str), "  "))
 
     return s
 
@@ -2822,13 +2813,6 @@ def _menu_path_info(node):
     return "(Top)" + path
 
 
-def _indent(s, n):
-    # Returns 's' with each line indented 'n' spaces. textwrap.indent() is not
-    # available in Python 2 (it's 3.3+).
-
-    return "\n".join(n*" " + line for line in s.split("\n"))
-
-
 def _name_and_val_str(sc):
     # Custom symbol/choice printer that shows symbol values after symbols
 
@@ -3155,9 +3139,7 @@ def _is_num(name):
 
 
 def _getch_compat(win):
-    # Uses get_wch() if available (Python 3.3+) and getch() otherwise.
-    #
-    # Also falls back on getch() if get_wch() raises curses.error, to work
+    # Fall back on getch() if get_wch() raises curses.error, to work
     # around an issue when resizing the terminal on at least macOS Catalina.
     # See https://github.com/ulfalizer/Kconfiglib/issues/84.
     #
diff --git a/oldconfig.py b/oldconfig.py
index 53434b2..b66c842 100755
--- a/oldconfig.py
+++ b/oldconfig.py
@@ -32,11 +32,6 @@ import sys
 from kconfiglib import Symbol, Choice, BOOL, TRISTATE, HEX, standard_kconfig
 
 
-# Python 2/3 compatibility hack
-if sys.version_info[0] < 3:
-    input = raw_input
-
-
 def _main():
     # Earlier symbols in Kconfig files might depend on later symbols and become
     # visible if their values change. This flag is set to True if the value of
diff --git a/setup.cfg b/setup.cfg
index 185845e..7604a2c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,7 +1,3 @@
-[bdist_wheel]
-# We support both Python 2 and Python 3
-universal = 1
-
 [metadata]
 # Include the license file in wheels
 license_file = LICENSE.txt
diff --git a/setup.py b/setup.py
index 6b8d905..ca308d2 100644
--- a/setup.py
+++ b/setup.py
@@ -9,17 +9,11 @@ setuptools.setup(
     # MAJOR.MINOR.PATCH, per http://semver.org
     version="14.1.1a4",
     description="A flexible Python Kconfig implementation",
-
-    # Make sure that README.rst decodes on Python 3 in environments that use
+    # Make sure that README.rst decodes correctly in environments that use
     # the C locale (which implies ASCII), by explicitly giving the encoding.
-    #
-    # io.open() has the 'encoding' parameter on both Python 2 and 3. open()
-    # doesn't have it on Python 2. This lets us use the same code for both.
     long_description=io.open(
-        os.path.join(os.path.dirname(__file__), "README.rst"),
-        encoding="utf-8"
+        os.path.join(os.path.dirname(__file__), "README.rst"), encoding="utf-8"
     ).read(),
-
     url="https://github.com/zephyrproject-rtos/Kconfiglib",
     author='Zephyr Project',
     author_email="ci@zephyrproject.org",
@@ -64,9 +58,7 @@ setuptools.setup(
     # Note: windows-curses is not automatically installed on Windows anymore,
     # because it made Kconfiglib impossible to install on MSYS2 with pip
 
-    # Needs support for unnumbered {} in format() and argparse
-    python_requires=">=2.7,!=3.0.*,!=3.1.*",
-
+    python_requires=">=3.9",
     project_urls={
         "GitHub repository": "https://github.com/zephyrproject-rtos/Kconfiglib",
         "Examples": "https://github.com/zephyrproject-rtos/Kconfiglib/tree/master/examples",
@@ -80,16 +72,7 @@ setuptools.setup(
         "License :: OSI Approved :: ISC License (ISCL)",
         "Operating System :: POSIX",
         "Operating System :: Microsoft :: Windows",
-        "Programming Language :: Python :: 2",
-        "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.2",
-        "Programming Language :: Python :: 3.3",
-        "Programming Language :: Python :: 3.4",
-        "Programming Language :: Python :: 3.5",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
diff --git a/tests/reltest b/tests/reltest
index f0c0645..2a1d8db 100755
--- a/tests/reltest
+++ b/tests/reltest
@@ -1,8 +1,8 @@
 #!/usr/bin/env bash
 
-# Runs the test suite and all examples scripts with Python 2 and Python 3,
-# bailing immediately if anything fails. For the examples that aren't tested in
-# the test suite, we just confirm that they at least run.
+# Runs the test suite and all examples scripts, bailing immediately if anything
+# fails. For the examples that aren't tested in  the test suite, we just confirm
+# that they at least run.
 #
 # Should be run from the kernel root with  $ Kconfiglib/tests/reltest
 
@@ -21,7 +21,7 @@ test_script() {
 }
 
 if [ $# == "0" ]; then
-    py_execs="python2 python3"
+    py_execs="python3"
 else
     py_execs=$@
 fi
diff --git a/testsuite.py b/testsuite.py
index b4f5e2b..7bc9804 100644
--- a/testsuite.py
+++ b/testsuite.py
@@ -2699,16 +2699,12 @@ config PRINT_ME_TOO
 
     sys.path.pop(0)
 
-    # This test can fail on older Python 3.x versions, because they don't
-    # preserve dict insertion order during iteration. The output is still
-    # correct, just different.
-    if not (3, 0) <= sys.version_info <= (3, 5):
-        print("Testing KCONFIG_WARN_UNDEF")
+    print("Testing KCONFIG_WARN_UNDEF")
 
-        os.environ["KCONFIG_WARN_UNDEF"] = "y"
-        c = Kconfig("Kconfiglib/tests/Kundef", warn_to_stderr=False)
+    os.environ["KCONFIG_WARN_UNDEF"] = "y"
+    c = Kconfig("Kconfiglib/tests/Kundef", warn_to_stderr=False)
 
-        verify_equal("\n".join(c.warnings), """
+    verify_equal("\n".join(c.warnings), """
 warning: the int symbol INT (defined at Kconfiglib/tests/Kundef:8) has a non-int range [UNDEF_2 (undefined), 8 (undefined)]
 warning: undefined symbol UNDEF_1:
 
@@ -2747,7 +2743,7 @@ menu "menu"
 	visible if UNDEF_3
 """[1:-1])
 
-        os.environ.pop("KCONFIG_WARN_UNDEF")
+    os.environ.pop("KCONFIG_WARN_UNDEF")
 
 
     print("\nAll selftests passed\n" if all_passed else
@@ -2760,8 +2756,8 @@ def run_compatibility_tests():
 
     # Referenced inside the kernel Kconfig files.
     #
-    # The str() makes the type of the value 'str' on both Python 2 and Python 3,
-    # which is nice for some later dictionary key sanity checks.
+    # The str() makes the type of the value 'str', which is nice for some later
+    # dictionary key sanity checks.
 
     os.environ["KERNELVERSION"] = str(
         subprocess.check_output("make kernelversion", shell=True)
@@ -2932,13 +2928,10 @@ def test_sanity(arch, srcarch):
 
     kconf.write_autoconf("/dev/null")
 
-    # No tempfile.TemporaryDirectory in Python 2
-    tmpdir = tempfile.mkdtemp()
-    kconf.sync_deps(os.path.join(tmpdir, "deps"))  # Create
-    kconf.sync_deps(os.path.join(tmpdir, "deps"))  # Update
-    shutil.rmtree(tmpdir)
+    with tempfile.TemporaryDirectory() as tmpdir:
+        kconf.sync_deps(os.path.join(tmpdir, "deps"))  # Create
+        kconf.sync_deps(os.path.join(tmpdir, "deps"))  # Update
 
-    # Python 2/3 compatible
     for key, sym in kconf.syms.items():
         verify(isinstance(key, str), "weird key '{}' in syms dict".format(key))