nixpkgs / pkgs / development / interpreters / python / cpython / default.nix

{
  lib,
  stdenv,
  fetchurl,
  fetchpatch,
  fetchgit,

  # build dependencies
  autoconf-archive,
  autoreconfHook,
  nukeReferences,
  pkg-config,
  python-setup-hook,

  # high level switches
  withMinimalDeps ? false,

  # runtime dependencies
  bzip2,
  withExpat ? !withMinimalDeps,
  expat,
  libffi,
  libuuid,
  libxcrypt,
  withMpdecimal ? !withMinimalDeps,
  mpdecimal,
  ncurses,
  withOpenssl ? !withMinimalDeps,
  openssl,
  withSqlite ? !withMinimalDeps,
  sqlite,
  xz,
  zlib,
  zstd,

  # platform-specific dependencies
  bashNonInteractive,
  windows,

  # optional dependencies
  bluezSupport ? !withMinimalDeps && stdenv.hostPlatform.isLinux,
  bluez-headers,
  mimetypesSupport ? !withMinimalDeps,
  mailcap,
  tzdata,
  withGdbm ? !withMinimalDeps && !stdenv.hostPlatform.isWindows,
  gdbm,
  withReadline ? !withMinimalDeps && !stdenv.hostPlatform.isWindows,
  readline,

  # splicing/cross
  pythonAttr ? "python${sourceVersion.major}${sourceVersion.minor}",
  self,
  pkgsBuildBuild,
  pkgsBuildHost,
  pkgsBuildTarget,
  pkgsHostHost,
  pkgsTargetTarget,
  __splices ? { },

  # build customization
  sourceVersion,
  hash,
  passthruFun,
  stripConfig ? withMinimalDeps,
  stripIdlelib ? withMinimalDeps,
  stripTests ? withMinimalDeps,
  stripTkinter ? withMinimalDeps,
  rebuildBytecode ? !withMinimalDeps,
  stripBytecode ? true,
  includeSiteCustomize ? !withMinimalDeps,
  static ? stdenv.hostPlatform.isStatic,
  enableFramework ? false,
  noldconfigPatch ? ./. + "/${sourceVersion.major}.${sourceVersion.minor}/no-ldconfig.patch",
  enableGIL ? true,
  enableDebug ? false,

  # pgo (not reproducible) + -fno-semantic-interposition
  # https://docs.python.org/3/using/configure.html#cmdoption-enable-optimizations
  enableOptimizations ? false,

  # improves performance, but remains reproducible
  enableNoSemanticInterposition ? true,

  # enabling LTO on 32bit arch causes downstream packages to fail when linking
  enableLTO ?
    !withMinimalDeps
    && (stdenv.hostPlatform.isDarwin || (stdenv.hostPlatform.is64bit && stdenv.hostPlatform.isLinux)),

  # enable asserts to ensure the build remains reproducible
  reproducibleBuild ? false,

  # for the Python package set
  packageOverrides ? (self: super: { }),

  # tests
  testers,

  # allow pythonMinimal to prevent accidental dependencies it doesn't want
  # Having this as an option is useful to allow overriding, eg. adding things to
  # python3Minimal
  allowedReferenceNames ? if withMinimalDeps then [ "bashNonInteractive" ] else [ ],

}@inputs:

# Note: this package is used for bootstrapping fetchurl, and thus
# cannot use fetchpatch! All mutable patches (generated by GitHub or
# cgit) that are needed here should be included directly in Nixpkgs as
# files.

assert lib.assertMsg (
  enableFramework -> stdenv.hostPlatform.isDarwin
) "Framework builds are only supported on Darwin.";

assert lib.assertMsg (
  reproducibleBuild -> stripBytecode
) "Deterministic builds require stripping bytecode.";

assert lib.assertMsg (
  reproducibleBuild -> (!enableOptimizations)
) "Deterministic builds are not achieved when optimizations are enabled.";

assert lib.assertMsg (
  reproducibleBuild -> (!rebuildBytecode)
) "Deterministic builds are not achieved when (default unoptimized) bytecode is created.";

let
  inherit (lib)
    concatMapStringsSep
    concatStringsSep
    enableFeature
    getDev
    getLib
    optionals
    optionalString
    replaceStrings
    ;

  withLibxcrypt =
    (!withMinimalDeps)
    &&
      # mixes libc and libxcrypt headers and libs and causes segfaults on importing crypt
      (!stdenv.hostPlatform.isFreeBSD)
    &&
      # crypt module was removed in 3.13
      passthru.pythonOlder "3.13";

  buildPackages = pkgsBuildHost;
  inherit (passthru) pythonOnBuildForHost;

  tzdataSupport = !withMinimalDeps && tzdata != null && passthru.pythonAtLeast "3.9";

  passthru =
    let
      # When we override the interpreter we also need to override the spliced versions of the interpreter
      inputs' = lib.filterAttrs (n: v: n != "passthruFun" && !lib.isDerivation v) inputs;
      # Memoization of the splices to avoid re-evaluating this function for all combinations of splices e.g.
      # python3.pythonOnBuildForHost.pythonOnBuildForTarget == python3.pythonOnBuildForTarget by consuming
      # __splices as an arg and using the cache if populated.
      splices = {
        pythonOnBuildForBuild = override pkgsBuildBuild.${pythonAttr};
        pythonOnBuildForHost = override pkgsBuildHost.${pythonAttr};
        pythonOnBuildForTarget = override pkgsBuildTarget.${pythonAttr};
        pythonOnHostForHost = override pkgsHostHost.${pythonAttr};
        pythonOnTargetForTarget = lib.optionalAttrs (lib.hasAttr pythonAttr pkgsTargetTarget) (
          override pkgsTargetTarget.${pythonAttr}
        );
      }
      // __splices;
      override =
        attr:
        let
          python = attr.override (
            inputs'
            // {
              self = python;
              __splices = splices;
            }
          );
        in
        python;
    in
    passthruFun rec {
      inherit self sourceVersion packageOverrides;
      implementation = "cpython";
      libPrefix = "python${pythonVersion}${lib.optionalString (!enableGIL) "t"}";
      executable = libPrefix;
      pythonVersion = with sourceVersion; "${major}.${minor}";
      sitePackages = "lib/${libPrefix}/site-packages";
      inherit hasDistutilsCxxPatch pythonAttr;
      inherit (splices)
        pythonOnBuildForBuild
        pythonOnBuildForHost
        pythonOnBuildForTarget
        pythonOnHostForHost
        pythonOnTargetForTarget
        ;

      pythonABITags = [
        "abi3"
        "none"
        "cp${sourceVersion.major}${sourceVersion.minor}${lib.optionalString (!enableGIL) "t"}"
      ];
    };

  version = with sourceVersion; "${major}.${minor}.${patch}${suffix}";

  nativeBuildInputs = [
    nukeReferences
  ]
  ++
    optionals
      (
        (!stdenv.hostPlatform.isDarwin && !withMinimalDeps)
        || (stdenv.hostPlatform != stdenv.buildPlatform && stdenv.hostPlatform.isFreeBSD)
      )
      [
        autoconf-archive # needed for AX_CHECK_COMPILE_FLAG
        autoreconfHook
      ]
  ++
    optionals ((!stdenv.hostPlatform.isDarwin || passthru.pythonAtLeast "3.14") && !withMinimalDeps)
      [
        pkg-config
      ]
  ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
    buildPackages.stdenv.cc
    pythonOnBuildForHost
  ]
  ++
    optionals
      (
        stdenv.cc.isClang
        && (!stdenv.hostPlatform.useAndroidPrebuilt or false)
        && (enableLTO || enableOptimizations)
      )
      [
        stdenv.cc.cc.libllvm.out
      ];

  buildInputs = lib.filter (p: p != null) (
    optionals (!withMinimalDeps) [
      bzip2
      libffi
      libuuid
      ncurses
      xz
      zlib
    ]
    ++ optionals withLibxcrypt [
      libxcrypt
    ]
    ++ optionals withOpenssl [
      openssl
    ]
    ++ optionals withSqlite [
      sqlite
    ]
    ++ optionals withMpdecimal [
      mpdecimal
    ]
    ++ optionals withExpat [
      expat
    ]
    ++ optionals (passthru.pythonAtLeast "3.14") [
      zstd
    ]
    ++ optionals bluezSupport [
      bluez-headers
    ]
    ++ optionals stdenv.hostPlatform.isMinGW [
      windows.dlfcn
      windows.pthreads
    ]
    ++ optionals tzdataSupport [
      tzdata
    ]
    ++ optionals withGdbm [
      gdbm
    ]
    ++ optionals withReadline [
      readline
    ]
  );

  hasDistutilsCxxPatch = !(stdenv.cc.isGNU or false);

  pythonOnBuildForHostInterpreter =
    if stdenv.hostPlatform == stdenv.buildPlatform then
      "$out/bin/python"
    else
      pythonOnBuildForHost.interpreter;

  src = fetchurl {
    url =
      with sourceVersion;
      "https://www.python.org/ftp/python/${major}.${minor}.${patch}/Python-${version}.tar.xz";
    inherit hash;
  };

  # win32 is added by Fedora’s patch
  machdep = if stdenv.hostPlatform.isWindows then "win32" else stdenv.hostPlatform.parsed.kernel.name;

  # https://github.com/python/cpython/blob/e488e300f5c01289c10906c2e53a8e43d6de32d8/configure.ac#L428
  # The configure script uses "arm" as the CPU name for all 32-bit ARM
  # variants when cross-compiling, but native builds include the version
  # suffix, so we do the same.
  pythonHostPlatform =
    let
      cpu =
        {
          # According to PEP600, Python's name for the Power PC
          # architecture is "ppc", not "powerpc".  Without the Rosetta
          # Stone below, the PEP600 requirement that "${ARCH} matches
          # the return value from distutils.util.get_platform()" fails.
          # https://peps.python.org/pep-0600/
          powerpc = "ppc";
          powerpcle = "ppcle";
          powerpc64 = "ppc64";
          powerpc64le = "ppc64le";
        }
        .${stdenv.hostPlatform.parsed.cpu.name} or stdenv.hostPlatform.parsed.cpu.name;
    in
    "${machdep}-${cpu}";

  execSuffix = stdenv.hostPlatform.extensions.executable;
in
with passthru;
stdenv.mkDerivation (finalAttrs: {
  pname = "python3";
  inherit src version;

  inherit nativeBuildInputs;
  buildInputs =
    lib.optionals (!stdenv.hostPlatform.isWindows) [
      bashNonInteractive # only required for patchShebangs
    ]
    ++ buildInputs;

  prePatch = optionalString stdenv.hostPlatform.isDarwin ''
    substituteInPlace configure --replace-fail '`/usr/bin/arch`' '"i386"'
  '';

  patches = [
    # Disable the use of ldconfig in ctypes.util.find_library (since
    # ldconfig doesn't work on NixOS), and don't use
    # ctypes.util.find_library during the loading of the uuid module
    # (since it will do a futile invocation of gcc (!) to find
    # libuuid, slowing down program startup a lot).
    noldconfigPatch
  ]
  ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform && stdenv.hostPlatform.isFreeBSD) [
    # Cross compilation only supports a limited number of "known good"
    # configurations. If you're reading this and it's been a long time
    # since this diff, consider submitting this patch upstream!
    ./freebsd-cross.patch
  ]
  ++ optionals (pythonOlder "3.13") [
    # Make sure that the virtualenv activation scripts are
    # owner-writable, so venvs can be recreated without permission
    # errors.
    ./virtualenv-permissions.patch
  ]
  ++ optionals (pythonAtLeast "3.13") [
    ./3.13/virtualenv-permissions.patch
  ]
  ++ optionals mimetypesSupport [
    # Make the mimetypes module refer to the right file
    ./mimetypes.patch
  ]
  ++ optionals (pythonAtLeast "3.9" && pythonOlder "3.11" && stdenv.hostPlatform.isDarwin) [
    # Stop checking for TCL/TK in global macOS locations
    ./3.9/darwin-tcl-tk.patch
  ]
  ++ optionals (hasDistutilsCxxPatch && pythonOlder "3.12") [
    # Fix for http://bugs.python.org/issue1222585
    # Upstream distutils is calling C compiler to compile C++ code, which
    # only works for GCC and Apple Clang. This makes distutils to call C++
    # compiler when needed.
    (
      if pythonAtLeast "3.7" && pythonOlder "3.11" then
        ./3.7/python-3.x-distutils-C++.patch
      else if pythonAtLeast "3.11" then
        ./3.11/python-3.x-distutils-C++.patch
      else
        fetchpatch {
          url = "https://bugs.python.org/file48016/python-3.x-distutils-C++.patch";
          sha256 = "1h18lnpx539h5lfxyk379dxwr8m2raigcjixkf133l4xy3f4bzi2";
        }
    )
  ]
  ++ optionals (pythonAtLeast "3.7" && pythonOlder "3.12") [
    # LDSHARED now uses $CC instead of gcc. Fixes cross-compilation of extension modules.
    ./3.8/0001-On-all-posix-systems-not-just-Darwin-set-LDSHARED-if.patch
    # Use sysconfigdata to find headers. Fixes cross-compilation of extension modules.
    ./3.7/fix-finding-headers-when-cross-compiling.patch
  ]
  ++ optionals (pythonOlder "3.12") [
    # https://github.com/python/cpython/issues/90656
    ./loongarch-support.patch
    # fix failing tests with openssl >= 3.4
    # https://github.com/python/cpython/pull/127361
  ]
  ++ optionals (pythonAtLeast "3.11" && pythonOlder "3.13") [
    # backport fix for https://github.com/python/cpython/issues/95855
    ./platform-triplet-detection.patch
  ]
  ++ optionals (version == "3.13.10" || version == "3.14.1") [
    # https://github.com/python/cpython/issues/142218
    ./${lib.versions.majorMinor version}/gh-142218.patch
  ]
  ++ optionals (stdenv.hostPlatform.isMinGW) (
    let
      # https://src.fedoraproject.org/rpms/mingw-python3
      mingw-patch = fetchgit {
        name = "mingw-python-patches";
        url = "https://src.fedoraproject.org/rpms/mingw-python3.git";
        rev = "3edecdbfb4bbf1276d09cd5e80e9fb3dd88c9511"; # for python 3.11.9 at the time of writing.
        hash = "sha256-kpXoIHlz53+0FAm/fK99ZBdNUg0u13erOr1XP2FSkQY=";
      };
    in
    (map (f: "${mingw-patch}/${f}") [
      # The other patches in that repo are already applied to 3.11.10
      "mingw-python3_distutils.patch"
      "mingw-python3_frozenmain.patch"
      "mingw-python3_make-sysconfigdata.py-relocatable.patch"
      "mingw-python3_mods-failed.patch"
      "mingw-python3_module-select.patch"
      "mingw-python3_module-socket.patch"
      "mingw-python3_modules.patch"
      "mingw-python3_platform-mingw.patch"
      "mingw-python3_posix-layout.patch"
      "mingw-python3_pthread_threadid.patch"
      "mingw-python3_pythonw.patch"
      "mingw-python3_setenv.patch"
      "mingw-python3_win-modules.patch"
    ])
  );

  postPatch =
    optionalString (!stdenv.hostPlatform.isWindows) ''
      substituteInPlace Lib/subprocess.py \
        --replace-fail "'/bin/sh'" "'${bashNonInteractive}/bin/sh'"
    ''
    + optionalString mimetypesSupport ''
      substituteInPlace Lib/mimetypes.py \
        --replace-fail "@mime-types@" "${mailcap}"
    '';

  env = {
    CPPFLAGS = concatStringsSep " " (map (p: "-I${getDev p}/include") buildInputs);
    LDFLAGS = concatStringsSep " " (map (p: "-L${getLib p}/lib") buildInputs);
    LIBS = "${optionalString (!stdenv.hostPlatform.isDarwin && withLibxcrypt) "-lcrypt"}";
    NIX_LDFLAGS = lib.optionalString (stdenv.cc.isGNU && !stdenv.hostPlatform.isStatic) (
      {
        "glibc" = "-lgcc_s";
        "musl" = "-lgcc_eh";
      }
      ."${stdenv.hostPlatform.libc}" or ""
    );
    # Determinism: We fix the hashes of str, bytes and datetime objects.
    PYTHONHASHSEED = 0;
  };

  # https://docs.python.org/3/using/configure.html
  configureFlags = [
    "--without-ensurepip"
  ]
  ++ optionals withExpat [
    "--with-system-expat"
  ]
  ++ optionals withMpdecimal [
    "--with-system-libmpdec"
  ]
  ++ optionals withOpenssl [
    "--with-openssl=${openssl.dev}"
  ]
  ++ optionals tzdataSupport [
    "--with-tzpath=${tzdata}/share/zoneinfo"
  ]
  ++ optionals (execSuffix != "") [
    "--with-suffix=${execSuffix}"
  ]
  ++ optionals enableLTO [
    "--with-lto"
  ]
  ++ optionals (!static && !enableFramework) [
    "--enable-shared"
  ]
  ++ optionals enableFramework [
    "--enable-framework=${placeholder "out"}/Library/Frameworks"
  ]
  ++ optionals (pythonAtLeast "3.13") [
    (enableFeature enableGIL "gil")
  ]
  ++ optionals enableOptimizations [
    "--enable-optimizations"
  ]
  ++ optionals enableDebug [
    "--with-pydebug"
  ]
  ++ optionals withSqlite [
    "--enable-loadable-sqlite-extensions"
  ]
  ++ optionals withLibxcrypt [
    "CFLAGS=-I${libxcrypt}/include"
    "LIBS=-L${libxcrypt}/lib"
  ]
  ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
    "ac_cv_buggy_getaddrinfo=no"
    # Assume little-endian IEEE 754 floating point when cross compiling
    "ac_cv_little_endian_double=yes"
    "ac_cv_big_endian_double=no"
    "ac_cv_mixed_endian_double=no"
    "ac_cv_x87_double_rounding=yes"
    "ac_cv_tanh_preserves_zero_sign=yes"
    # Generally assume that things are present and work
    "ac_cv_posix_semaphores_enabled=yes"
    "ac_cv_broken_sem_getvalue=no"
    "ac_cv_wchar_t_signed=yes"
    "ac_cv_rshift_extends_sign=yes"
    "ac_cv_broken_nice=no"
    "ac_cv_broken_poll=no"
    "ac_cv_working_tzset=yes"
    "ac_cv_have_long_long_format=yes"
    "ac_cv_have_size_t_format=yes"
    "ac_cv_computed_gotos=yes"
    # Both fail when building for windows, normally configure checks this by itself but on other platforms this is set to yes always.
    "ac_cv_file__dev_ptmx=${lib.boolToYesNo (!stdenv.hostPlatform.isWindows)}"
    "ac_cv_file__dev_ptc=${lib.boolToYesNo (!stdenv.hostPlatform.isWindows)}"
  ]
  ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform && pythonAtLeast "3.11") [
    "--with-build-python=${pythonOnBuildForHostInterpreter}"
  ]
  ++ optionals stdenv.hostPlatform.isLinux [
    # Never even try to use lchmod on linux,
    # don't rely on detecting glibc-isms.
    "ac_cv_func_lchmod=no"
  ]
  ++ optionals static [
    "--disable-test-modules"
    "LDFLAGS=-static"
    "MODULE_BUILDTYPE=static"
  ]
  ++ optionals (stdenv.hostPlatform.isStatic && stdenv.hostPlatform.isMusl) [
    # dlopen is a no-op in static musl builds, and since we build everything without -fPIC it's better not to pretend.
    "ac_cv_func_dlopen=no"
  ];

  preConfigure = ''
    # Attempt to purify some of the host info collection
    sed -E -i -e 's/uname -r/echo/g' -e 's/uname -n/echo nixpkgs/g' config.guess
    sed -E -i -e 's/uname -r/echo/g' -e 's/uname -n/echo nixpkgs/g' configure
  ''
  + optionalString (pythonOlder "3.12") ''
    # Improve purity
    for path in /usr /sw /opt /pkg; do
      substituteInPlace ./setup.py --replace-warn $path /no-such-path
    done
  ''
  + optionalString (stdenv.hostPlatform.isDarwin && pythonOlder "3.12") ''
    # Fix _ctypes module compilation
    export NIX_CFLAGS_COMPILE+=" -DUSING_APPLE_OS_LIBFFI=1"
  ''
  + optionalString stdenv.hostPlatform.isDarwin ''
    # Override the auto-detection in setup.py, which assumes a universal build
    export PYTHON_DECIMAL_WITH_MACHINE=${if stdenv.hostPlatform.isAarch64 then "uint128" else "x64"}
    # Ensure that modern platform features are enabled on Darwin in spite of having no version suffix.
    sed -E -i -e 's|Darwin/\[12\]\[0-9\]\.\*|Darwin/*|' configure
  ''
  + optionalString (pythonAtLeast "3.11") ''
    # Also override the auto-detection in `configure`.
    substituteInPlace configure \
      --replace-fail 'libmpdec_machine=universal' 'libmpdec_machine=${
        if stdenv.hostPlatform.isAarch64 then "uint128" else "x64"
      }'
  ''
  + optionalString stdenv.hostPlatform.isWindows ''
    export NIX_CFLAGS_COMPILE+=" -Wno-error=incompatible-pointer-types"
  ''
  + optionalString stdenv.hostPlatform.isMusl ''
    export NIX_CFLAGS_COMPILE+=" -DTHREAD_STACK_SIZE=0x100000"
  ''
  +

    # enableNoSemanticInterposition essentially sets that CFLAG -fno-semantic-interposition
    # which changes how symbols are looked up. This essentially means we can't override
    # libpython symbols via LD_PRELOAD anymore. This is common enough as every build
    # that uses --enable-optimizations has the same "issue".
    #
    # The Fedora wiki has a good article about their journey towards enabling this flag:
    # https://fedoraproject.org/wiki/Changes/PythonNoSemanticInterpositionSpeedup
    optionalString enableNoSemanticInterposition ''
      export CFLAGS_NODIST="-fno-semantic-interposition"
    '';

  setupHook = python-setup-hook sitePackages;

  postInstall =
    let
      # References *not* to nuke from (sys)config files
      keep-references = concatMapStringsSep " " (val: "-e ${val}") (
        [
          (placeholder "out")
        ]
        ++ lib.optional withLibxcrypt libxcrypt
        ++ lib.optional tzdataSupport tzdata
      );
    in
    lib.optionalString enableFramework ''
      for dir in include lib share; do
        ln -s $out/Library/Frameworks/Python.framework/Versions/Current/$dir $out/$dir
      done
    ''
    + ''
      # needed for some packages, especially packages that backport functionality
      # to 2.x from 3.x
      for item in $out/lib/${libPrefix}/test/*; do
        if [[ "$item" != */test_support.py*
           && "$item" != */test/support
           && "$item" != */test/libregrtest
           && "$item" != */test/regrtest.py* ]]; then
          rm -rf "$item"
        else
          echo $item
        fi
      done
    ''
    + lib.optionalString (!static) ''
      touch $out/lib/${libPrefix}/test/__init__.py
    ''
    + ''

      # Determinism: Windows installers were not deterministic.
      # We're also not interested in building Windows installers.
      find "$out" -name 'wininst*.exe' | xargs -r rm -f

      # Use Python3 as default python
      ln -s "$out/bin/idle3" "$out/bin/idle"
      ln -s "$out/bin/pydoc3" "$out/bin/pydoc"
      ln -s "$out/bin/python3${execSuffix}" "$out/bin/python${execSuffix}"
      ln -s "$out/bin/python3-config" "$out/bin/python-config"
      ln -s "$out/lib/pkgconfig/python3.pc" "$out/lib/pkgconfig/python.pc"
      ln -sL "$out/share/man/man1/python3.1.gz" "$out/share/man/man1/python.1.gz"

      # Get rid of retained dependencies on -dev packages, and remove
      # some $TMPDIR references to improve binary reproducibility.
      # Note that the .pyc file of _sysconfigdata.py should be regenerated!
      for i in $out/lib/${libPrefix}/_sysconfigdata*.py $out/lib/${libPrefix}/config-${sourceVersion.major}.${sourceVersion.minor}*/Makefile; do
         sed -i $i -e "s|$TMPDIR|/no-such-path|g"
      done

      # Further get rid of references. https://github.com/NixOS/nixpkgs/issues/51668
      find $out/lib/python*/config-* -type f -print -exec nuke-refs ${keep-references} '{}' +
      find $out/lib -name '_sysconfigdata*.py*' -print -exec nuke-refs ${keep-references} '{}' +

      # Make the sysconfigdata module accessible on PYTHONPATH
      # This allows build Python to import host Python's sysconfigdata
      mkdir -p "$out/${sitePackages}"
      ln -s "$out/lib/${libPrefix}/"_sysconfigdata*.py "$out/${sitePackages}/"
    ''
    + optionalString (pythonAtLeast "3.14") ''
      # Get rid of retained dependencies on -dev packages, and remove from _sysconfig_vars*.json introduced with Python3.14
      for i in $out/lib/${libPrefix}/_sysconfig_vars*.json; do
         sed -i $i -e "s|$TMPDIR|/no-such-path|g"
      done
      find $out/lib -name '_sysconfig_vars*.json*' -print -exec nuke-refs ${keep-references} '{}' +
      ln -s "$out/lib/${libPrefix}/"_sysconfig_vars*.json "$out/${sitePackages}/"
    ''
    + optionalString stripConfig ''
      rm -R $out/bin/python*-config $out/lib/python*/config-*
    ''
    + optionalString stripIdlelib ''
      # Strip IDLE (and turtledemo, which uses it)
      rm -R $out/bin/idle* $out/lib/python*/{idlelib,turtledemo}
    ''
    + optionalString stripTkinter ''
      rm -R $out/lib/python*/tkinter
    ''
    + optionalString stripTests ''
      # Strip tests
      rm -R $out/lib/python*/test $out/lib/python*/**/test{,s}
    ''
    + optionalString includeSiteCustomize ''
      # Include a sitecustomize.py file
      cp ${../sitecustomize.py} $out/${sitePackages}/sitecustomize.py
    ''
    + optionalString stripBytecode ''
      # Determinism: deterministic bytecode
      # First we delete all old bytecode.
      find $out -type d -name __pycache__ -print0 | xargs -0 -I {} rm -rf "{}"
    ''
    + optionalString rebuildBytecode ''
      # Python 3.7 implements PEP 552, introducing support for deterministic bytecode.
      # compileall uses the therein introduced checked-hash method by default when
      # `SOURCE_DATE_EPOCH` is set.
      # We exclude lib2to3 because that's Python 2 code which fails
      # We build 3 levels of optimized bytecode. Note the default level, without optimizations,
      # is not reproducible yet. https://bugs.python.org/issue29708
      # Not creating bytecode will result in a large performance loss however, so we do build it.
      find $out -name "*.py" | ${pythonOnBuildForHostInterpreter} -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | ${pythonOnBuildForHostInterpreter} -O  -m compileall -q -f -x "lib2to3" -i -
      find $out -name "*.py" | ${pythonOnBuildForHostInterpreter} -OO -m compileall -q -f -x "lib2to3" -i -
    ''
    + ''
      # *strip* shebang from libpython gdb script - it should be dual-syntax and
      # interpretable by whatever python the gdb in question is using, which may
      # not even match the major version of this python. doing this after the
      # bytecode compilations for the same reason - we don't want bytecode generated.
      mkdir -p $out/share/gdb
      sed '/^#!/d' Tools/gdb/libpython.py > $out/share/gdb/libpython.py

      # Disable system-wide pip installation. See https://peps.python.org/pep-0668/.
      cat <<'EXTERNALLY_MANAGED' > $out/lib/${libPrefix}/EXTERNALLY-MANAGED
      [externally-managed]
      Error=This command has been disabled as it tries to modify the immutable
       `/nix/store` filesystem.

       To use Python with Nix and nixpkgs, have a look at the online documentation:
       <https://nixos.org/manual/nixpkgs/stable/#python>.
      EXTERNALLY_MANAGED
    ''
    + optionalString stdenv.hostPlatform.isWindows ''
      # Shebang files that link against the build python. Shebang don’t work on windows
      rm $out/bin/2to3*
      rm $out/bin/idle*
      rm $out/bin/pydoc*

      echo linking DLLs for python’s compiled librairies
      linkDLLsInfolder $out/lib/python*/lib-dynload/
    '';

  preFixup = lib.optionalString (stdenv.hostPlatform != stdenv.buildPlatform) ''
    # Ensure patch-shebangs uses shebangs of host interpreter.
    export PATH=${lib.makeBinPath [ "$out" ]}:$PATH
  '';

  # Add CPython specific setup-hook that configures distutils.sysconfig to
  # always load sysconfigdata from host Python.
  postFixup = lib.optionalString (!stdenv.hostPlatform.isDarwin) ''
    # https://github.com/python/cpython/blob/e488e300f5c01289c10906c2e53a8e43d6de32d8/configure.ac#L78
    sysconfigdataName="$(make --eval $'print-sysconfigdata-name:
    \t@echo _sysconfigdata_$(ABIFLAGS)_$(MACHDEP)_$(MULTIARCH) ' print-sysconfigdata-name)"

    # The CPython interpreter contains a _sysconfigdata_<platform specific suffix>
    # module that is imported by the sysconfig and distutils.sysconfig modules.
    # The sysconfigdata module is generated at build time and contains settings
    # required for building Python extension modules, such as include paths and
    # other compiler flags. By default, the sysconfigdata module is loaded from
    # the currently running interpreter (ie. the build platform interpreter), but
    # when cross-compiling we want to load it from the host platform interpreter.
    # This can be done using the _PYTHON_SYSCONFIGDATA_NAME environment variable.
    # The _PYTHON_HOST_PLATFORM variable also needs to be set to get the correct
    # platform suffix on extension modules. The correct values for these variables
    # are not documented, and must be derived from the configure script (see links
    # below).
    cat <<EOF >> "$out/nix-support/setup-hook"
    sysconfigdataHook() {
      if [ "\$1" = '$out' ]; then
        export _PYTHON_HOST_PLATFORM='${pythonHostPlatform}'
        export _PYTHON_SYSCONFIGDATA_NAME='$sysconfigdataName'
      fi
    }

    addEnvHooks "\$hostOffset" sysconfigdataHook
    EOF
  '';

  # Enforce that we don't have references to the OpenSSL -dev package, which we
  # explicitly specify in our configure flags above.
  disallowedReferences =
    lib.optionals (withOpenssl && !static && !enableFramework) [
      openssl.dev
    ]
    ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
      # Ensure we don't have references to build-time packages.
      # These typically end up in shebangs.
      pythonOnBuildForHost
      buildPackages.bashNonInteractive
    ];

  # Optionally set allowedReferences to guarantee minimal dependencies
  # Allows python3Minimal to stay minimal and not have deps added by accident
  # Doesn't do anything if allowedReferenceNames is empty (was not set)
  ${if allowedReferenceNames != [ ] then "allowedReferences" else null} =
    # map allowed names to their derivations
    (map (name: inputs.${name}) allowedReferenceNames) ++ [
      # any version of python depends on libc and libgcc
      stdenv.cc.cc.lib
      stdenv.cc.libc
      # allows python referring to its own store path
      "out"
    ];

  separateDebugInfo = true;
  __structuredAttrs = true;

  passthru = passthru // {
    doc = stdenv.mkDerivation {
      inherit src;
      name = "python${pythonVersion}-${version}-doc";

      postPatch = lib.optionalString (pythonAtLeast "3.9" && pythonOlder "3.11") ''
        substituteInPlace Doc/tools/extensions/pyspecific.py \
          --replace-fail "from sphinx.util import status_iterator" "from sphinx.util.display import status_iterator"
      '';

      dontConfigure = true;

      dontBuild = true;

      sphinxRoot = "Doc";

      postInstallSphinx = ''
        mv $out/share/doc/* $out/share/doc/python${pythonVersion}-${version}
      '';

      nativeBuildInputs = with pkgsBuildBuild.python3.pkgs; [
        sphinxHook
        python-docs-theme
      ];
    };

    tests = passthru.tests // {
      pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;
    };
  };

  enableParallelBuilding = true;

  meta = {
    homepage = "https://www.python.org";
    changelog =
      let
        majorMinor = lib.versions.majorMinor version;
        dashedVersion = lib.replaceStrings [ "." "a" "b" ] [ "-" "-alpha-" "-beta-" ] version;
      in
      if sourceVersion.suffix == "" then
        "https://docs.python.org/release/${version}/whatsnew/changelog.html"
      else
        "https://docs.python.org/${majorMinor}/whatsnew/changelog.html#python-${dashedVersion}";
    description = "High-level dynamically-typed programming language";
    longDescription = ''
      Python is a remarkably powerful dynamic programming language that
      is used in a wide variety of application domains. Some of its key
      distinguishing features include: clear, readable syntax; strong
      introspection capabilities; intuitive object orientation; natural
      expression of procedural code; full modularity, supporting
      hierarchical packages; exception-based error handling; and very
      high level dynamic data types.
    '';
    license = lib.licenses.psfl;
    pkgConfigModules = [ "python3" ];
    platforms =
      lib.platforms.linux ++ lib.platforms.darwin ++ lib.platforms.windows ++ lib.platforms.freebsd;
    mainProgram = executable;
    teams = [ lib.teams.python ];
    # static build on x86_64-darwin/aarch64-darwin breaks with:
    # configure: error: C compiler cannot create executables

    # mingw patches only apply to Python 3.11 currently
    broken =
      (lib.versions.minor version != "11" && stdenv.hostPlatform.isWindows)
      || (stdenv.hostPlatform.isStatic && stdenv.hostPlatform.isDarwin);
  };
})