build: remove support for Python 2

PR-URL: nodejs#36691
Fixes: nodejs#25789
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Ujjwal Sharma <ryzokuken@disroot.org>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Beth Griggs <bgriggs@redhat.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>

BUILDING.md

@@ -19,7 +19,7 @@ file a new issue.
     * [OpenSSL asm support](#openssl-asm-support)
   * [Previous versions of this document](#previous-versions-of-this-document)
 * [Building Node.js on supported platforms](#building-nodejs-on-supported-platforms)
-  * [Note about Python 2 and Python 3](#note-about-python-2-and-python-3)
+  * [Note about Python](#note-about-python)
   * [Unix and macOS](#unix-and-macos)
     * [Unix prerequisites](#unix-prerequisites)
     * [macOS prerequisites](#macos-prerequisites)
@@ -225,29 +225,23 @@ Consult previous versions of this document for older versions of Node.js:
 
 ## Building Node.js on supported platforms
 
-### Note about Python 2 and Python 3
-
-The Node.js project supports both Python 3 and Python 2 for building.
-If both are installed Python 3 will be used. If only Python 2 is available
-it will be used instead. When possible we recommend that you build and
-test with Python 3.
+### Note about Python
 
+The Node.js project supports Python >= 3 for building and testing.
 ### Unix and macOS
 
 #### Unix prerequisites
 
 * `gcc` and `g++` >= 8.3 or newer, or
 * GNU Make 3.81 or newer
-* Python (see note above)
-  * Python 2.7
-  * Python 3.5, 3.6, 3.7, and 3.8
+* Python 3.6, 3.7, 3.8, and 3.9 (see note above)
 
 Installation via Linux package manager can be achieved with:
 
-* Ubuntu, Debian: `sudo apt-get install python g++ make`
-* Fedora: `sudo dnf install python gcc-c++ make`
-* CentOS and RHEL: `sudo yum install python gcc-c++ make`
-* OpenSUSE: `sudo zypper install python gcc-c++ make`
+* Ubuntu, Debian: `sudo apt-get install python3 g++ make`
+* Fedora: `sudo dnf install python3 gcc-c++ make`
+* CentOS and RHEL: `sudo yum install python3 gcc-c++ make`
+* OpenSUSE: `sudo zypper install python3 gcc-c++ make`
 * Arch Linux, Manjaro: `sudo pacman -S python gcc make`
 
 FreeBSD and OpenBSD users may also need to install `libexecinfo`.
@@ -256,10 +250,8 @@ Python 3 users may also need to install `python3-distutils`.
 
 #### macOS prerequisites
 
-* Xcode Command Line Tools >= 11 for macOS
-* Python (see note above)
-  * Python 2.7
-  * Python 3.5, 3.6, 3.7, and 3.8
+* Xcode Command Line Tools >= 10 for macOS
+* Python 3.6, 3.7, 3.8, and 3.9 (see note above)
 
 macOS users can install the `Xcode Command Line Tools` by running
 `xcode-select --install`. Alternatively, if you already have the full Xcode
@@ -568,7 +560,7 @@ to run it again before invoking `make -j4`.
 
 ##### Option 1: Manual install
 
-* [Python 3.8](https://www.python.org/downloads/)
+* [Python 3.9](https://www.microsoft.com/en-us/p/python-39/9p7qfqmjrfp7)
 * The "Desktop development with C++" workload from
   [Visual Studio 2019](https://visualstudio.microsoft.com/downloads/) or
   the "Visual C++ build tools" workload from the
@@ -606,8 +598,7 @@ packages:
 
 * [Git for Windows](https://chocolatey.org/packages/git) with the `git` and
   Unix tools added to the `PATH`
-* [Python 3.x](https://chocolatey.org/packages/python) and
-  [legacy Python](https://chocolatey.org/packages/python2)
+* [Python 3.x](https://chocolatey.org/packages/python)
 * [Visual Studio 2019 Build Tools](https://chocolatey.org/packages/visualstudio2019buildtools)
   with [Visual C++ workload](https://chocolatey.org/packages/visualstudio2019-workload-vctools)
 * [NetWide Assembler](https://chocolatey.org/packages/nasm)

configure

@@ -1,17 +1,14 @@
 #!/bin/sh
 
-# Locate an acceptable python interpreter and then re-execute the script.
+# Locate an acceptable Python interpreter and then re-execute the script.
 # Note that the mix of single and double quotes is intentional,
 # as is the fact that the ] goes on a new line.
 _=[ 'exec' '/bin/sh' '-c' '''
-test ${FORCE_PYTHON2} && exec python2 "$0" "$@"  # workaround for gclient
 command -v python3.9 >/dev/null && exec python3.9 "$0" "$@"
 command -v python3.8 >/dev/null && exec python3.8 "$0" "$@"
 command -v python3.7 >/dev/null && exec python3.7 "$0" "$@"
 command -v python3.6 >/dev/null && exec python3.6 "$0" "$@"
-command -v python3.5 >/dev/null && exec python3.5 "$0" "$@"
 command -v python3 >/dev/null && exec python3 "$0" "$@"
-command -v python2.7 >/dev/null && exec python2.7 "$0" "$@"
 exec python "$0" "$@"
 ''' "$0" "$@"
 ]
@@ -20,16 +17,15 @@ del _
 import sys
 from distutils.spawn import find_executable
 
-print('Node.js configure: Found Python {0}.{1}.{2}...'.format(*sys.version_info))
-acceptable_pythons = ((3, 9), (3, 8), (3, 7), (3, 6), (3, 5), (2, 7))
+print('Node.js configure: Found Python {}.{}.{}...'.format(*sys.version_info))
+acceptable_pythons = ((3, 9), (3, 8), (3, 7), (3, 6))
 if sys.version_info[:2] in acceptable_pythons:
   import configure
 else:
-  python_cmds = ['python{0}.{1}'.format(*vers) for vers in acceptable_pythons]
-  sys.stderr.write('Please use {0}.\n'.format(' or '.join(python_cmds)))
+  python_cmds = ['python{}.{}'.format(*vers) for vers in acceptable_pythons]
+  sys.stderr.write('Please use {}.\n'.format(' or '.join(python_cmds)))
   for python_cmd in python_cmds:
       python_cmd_path = find_executable(python_cmd)
       if python_cmd_path and 'pyenv/shims' not in python_cmd_path:
-        sys.stderr.write('\t{0} {1}\n'.format(python_cmd_path,
-                                              ' '.join(sys.argv[:1])))
+        sys.stderr.write('\t{} {}\n'.format(python_cmd_path, ' '.join(sys.argv[:1])))
   sys.exit(1)

configure.py

@@ -1827,7 +1827,7 @@ def make_bin_override():
   if sys.platform == 'win32':
     raise Exception('make_bin_override should not be called on win32.')
   # If the system python is not the python we are running (which should be
-  # python 2), then create a directory with a symlink called `python` to our
+  # python 3), then create a directory with a symlink called `python` to our
   # sys.executable. This directory will be prefixed to the PATH, so that
   # other tools that shell out to `python` will use the appropriate python
 

doc/guides/maintaining-the-build-files.md

@@ -8,7 +8,7 @@ On how to build the Node.js core, see [Building Node.js](../../BUILDING.md).
 
 There are three main build files that may be directly run when building Node.js:
 
-* `configure`: A Python 2 script that detects system capabilities and runs
+* `configure`: A Python script that detects system capabilities and runs
   [GYP][]. It generates `config.gypi` which includes parameters used by GYP to
   create platform-dependent build files. Its output is usually in one of these
   formats: Makefile, MSbuild, ninja, or XCode project files (the main