path: root/eclass/python-utils-r1.eclass

# Copyright 1999-2024 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

# @ECLASS: python-utils-r1.eclass
# @MAINTAINER:
# Python team <python@gentoo.org>
# @AUTHOR:
# Author: Michał Górny <mgorny@gentoo.org>
# Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
# @SUPPORTED_EAPIS: 7 8
# @BLURB: Utility functions for packages with Python parts.
# @DESCRIPTION:
# A utility eclass providing functions to query Python implementations,
# install Python modules and scripts.
#
# This eclass does not set any metadata variables nor export any phase
# functions. It can be inherited safely.
#
# For more information, please see the Python Guide:
# https://projects.gentoo.org/python/guide/

# NOTE: When dropping support for EAPIs here, we need to update
# metadata/install-qa-check.d/60python-pyc
# See bug #704286, bug #781878

case ${EAPI} in
	7|8) ;;
	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
esac

if [[ ! ${_PYTHON_UTILS_R1_ECLASS} ]]; then
_PYTHON_UTILS_R1_ECLASS=1

[[ ${EAPI} == 7 ]] && inherit eapi8-dosym
inherit multiprocessing toolchain-funcs

# @ECLASS_VARIABLE: _PYTHON_ALL_IMPLS
# @INTERNAL
# @DESCRIPTION:
# All supported Python implementations, most preferred last.
_PYTHON_ALL_IMPLS=(
	pypy3
	python3_{10..13}
)
readonly _PYTHON_ALL_IMPLS

# @ECLASS_VARIABLE: _PYTHON_HISTORICAL_IMPLS
# @INTERNAL
# @DESCRIPTION:
# All historical Python implementations that are no longer supported.
_PYTHON_HISTORICAL_IMPLS=(
	jython2_7
	pypy pypy1_{8,9} pypy2_0
	python2_{5..7}
	python3_{1..9}
)
readonly _PYTHON_HISTORICAL_IMPLS

# @ECLASS_VARIABLE: PYTHON_COMPAT_NO_STRICT
# @INTERNAL
# @DESCRIPTION:
# Set to a non-empty value in order to make eclass tolerate (ignore)
# unknown implementations in PYTHON_COMPAT.
#
# This is intended to be set by the user when using ebuilds that may
# have unknown (newer) implementations in PYTHON_COMPAT. The assumption
# is that the ebuilds are intended to be used within multiple contexts
# which can involve revisions of this eclass that support a different
# set of Python implementations.

# @FUNCTION: _python_verify_patterns
# @USAGE: <pattern>...
# @INTERNAL
# @DESCRIPTION:
# Verify whether the patterns passed to the eclass function are correct
# (i.e. can match any valid implementation).  Dies on wrong pattern.
_python_verify_patterns() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	for pattern; do
		case ${pattern} in
			-[23]|3.[89]|3.1[0-3])
				continue
				;;
		esac

		for impl in "${_PYTHON_ALL_IMPLS[@]}" "${_PYTHON_HISTORICAL_IMPLS[@]}"
		do
			[[ ${impl} == ${pattern/./_} ]] && continue 2
		done

		die "Invalid implementation pattern: ${pattern}"
	done
}

# @FUNCTION: _python_set_impls
# @INTERNAL
# @DESCRIPTION:
# Check PYTHON_COMPAT for well-formedness and validity, then set
# two global variables:
#
# - _PYTHON_SUPPORTED_IMPLS containing valid implementations supported
#   by the ebuild (PYTHON_COMPAT - dead implementations),
#
# - and _PYTHON_UNSUPPORTED_IMPLS containing valid implementations that
#   are not supported by the ebuild.
#
# Implementations in both variables are ordered using the pre-defined
# eclass implementation ordering.
#
# This function must be called once in global scope by an eclass
# utilizing PYTHON_COMPAT.
_python_set_impls() {
	local i

	# TODO: drop BASH_VERSINFO check when we require EAPI 8
	if [[ ${BASH_VERSINFO[0]} -ge 5 ]]; then
		[[ ${PYTHON_COMPAT@a} == *a* ]]
	else
		[[ $(declare -p PYTHON_COMPAT) == "declare -a"* ]]
	fi
	if [[ ${?} -ne 0 ]]; then
		if ! declare -p PYTHON_COMPAT &>/dev/null; then
			die 'PYTHON_COMPAT not declared.'
		else
			die 'PYTHON_COMPAT must be an array.'
		fi
	fi

	local obsolete=()
	if [[ ! ${PYTHON_COMPAT_NO_STRICT} ]]; then
		for i in "${PYTHON_COMPAT[@]}"; do
			# check for incorrect implementations
			# we're using pattern matching as an optimization
			# please keep them in sync with _PYTHON_ALL_IMPLS
			# and _PYTHON_HISTORICAL_IMPLS
			case ${i} in
				pypy3|python3_9|python3_1[0-3])
					;;
				jython2_7|pypy|pypy1_[89]|pypy2_0|python2_[5-7]|python3_[1-9])
					obsolete+=( "${i}" )
					;;
				*)
					if has "${i}" "${_PYTHON_ALL_IMPLS[@]}" \
						"${_PYTHON_HISTORICAL_IMPLS[@]}"
					then
						die "Mis-synced patterns in _python_set_impls: missing ${i}"
					else
						die "Invalid implementation in PYTHON_COMPAT: ${i}"
					fi
			esac
		done
	fi

	local supp=() unsupp=()

	for i in "${_PYTHON_ALL_IMPLS[@]}"; do
		if has "${i}" "${PYTHON_COMPAT[@]}"; then
			supp+=( "${i}" )
		else
			unsupp+=( "${i}" )
		fi
	done

	if [[ ! ${supp[@]} ]]; then
		die "No supported implementation in PYTHON_COMPAT."
	fi

	if [[ ${_PYTHON_SUPPORTED_IMPLS[@]} ]]; then
		# set once already, verify integrity
		if [[ ${_PYTHON_SUPPORTED_IMPLS[@]} != ${supp[@]} ]]; then
			eerror "Supported impls (PYTHON_COMPAT) changed between inherits!"
			eerror "Before: ${_PYTHON_SUPPORTED_IMPLS[*]}"
			eerror "Now   : ${supp[*]}"
			die "_PYTHON_SUPPORTED_IMPLS integrity check failed"
		fi
		if [[ ${_PYTHON_UNSUPPORTED_IMPLS[@]} != ${unsupp[@]} ]]; then
			eerror "Unsupported impls changed between inherits!"
			eerror "Before: ${_PYTHON_UNSUPPORTED_IMPLS[*]}"
			eerror "Now   : ${unsupp[*]}"
			die "_PYTHON_UNSUPPORTED_IMPLS integrity check failed"
		fi
	else
		_PYTHON_SUPPORTED_IMPLS=( "${supp[@]}" )
		_PYTHON_UNSUPPORTED_IMPLS=( "${unsupp[@]}" )
		readonly _PYTHON_SUPPORTED_IMPLS _PYTHON_UNSUPPORTED_IMPLS
	fi
}

# @FUNCTION: _python_impl_matches
# @USAGE: <impl> [<pattern>...]
# @INTERNAL
# @DESCRIPTION:
# Check whether the specified <impl> matches at least one
# of the patterns following it. Return 0 if it does, 1 otherwise.
# Matches if no patterns are provided.
#
# <impl> can be in PYTHON_COMPAT or EPYTHON form. The patterns
# can either be fnmatch-style or stdlib versions, e.g. "3.8", "3.9".
# In the latter case, pypy3 will match if there is at least one pypy3
# version matching the stdlib version.
_python_impl_matches() {
	[[ ${#} -ge 1 ]] || die "${FUNCNAME}: takes at least 1 parameter"
	[[ ${#} -eq 1 ]] && return 0

	local impl=${1/./_} pattern
	shift

	for pattern; do
		case ${pattern} in
			-2|python2*|pypy)
				if [[ ${EAPI} != 7 ]]; then
					eerror
					eerror "Python 2 is no longer supported in Gentoo, please remove Python 2"
					eerror "${FUNCNAME[1]} calls."
					die "Passing ${pattern} to ${FUNCNAME[1]} is banned in EAPI ${EAPI}"
				fi
				;;
			-3)
				# NB: "python3*" is fine, as "not pypy3"
				if [[ ${EAPI} != 7 ]]; then
					eerror
					eerror "Python 2 is no longer supported in Gentoo, please remove Python 2"
					eerror "${FUNCNAME[1]} calls."
					die "Passing ${pattern} to ${FUNCNAME[1]} is banned in EAPI ${EAPI}"
				fi
				return 0
				;;
			3.10)
				[[ ${impl} == python${pattern/./_} || ${impl} == pypy3 ]] &&
					return 0
				;;
			3.8|3.9|3.1[1-3])
				[[ ${impl} == python${pattern/./_} ]] && return 0
				;;
			*)
				# unify value style to allow lax matching
				[[ ${impl} == ${pattern/./_} ]] && return 0
				;;
		esac
	done

	return 1
}

# @ECLASS_VARIABLE: PYTHON
# @DEFAULT_UNSET
# @DESCRIPTION:
# The absolute path to the current Python interpreter.
#
# This variable is set automatically in the following contexts:
#
# python-r1: Set in functions called by python_foreach_impl() or after
# calling python_setup().
#
# python-single-r1: Set after calling python-single-r1_pkg_setup().
#
# distutils-r1: Set within any of the python sub-phase functions.
#
# Example value:
# @CODE
# /usr/bin/python2.7
# @CODE

# @ECLASS_VARIABLE: EPYTHON
# @DEFAULT_UNSET
# @DESCRIPTION:
# The executable name of the current Python interpreter.
#
# This variable is set automatically in the following contexts:
#
# python-r1: Set in functions called by python_foreach_impl() or after
# calling python_setup().
#
# python-single-r1: Set after calling python-single-r1_pkg_setup().
#
# distutils-r1: Set within any of the python sub-phase functions.
#
# Example value:
# @CODE
# python2.7
# @CODE

# @FUNCTION: _python_export
# @USAGE: [<impl>] <variables>...
# @INTERNAL
# @DESCRIPTION:
# Set and export the Python implementation-relevant variables passed
# as parameters.
#
# The optional first parameter may specify the requested Python
# implementation (either as PYTHON_TARGETS value, e.g. python2_7,
# or an EPYTHON one, e.g. python2.7). If no implementation passed,
# the current one will be obtained from ${EPYTHON}.
#
# The variables which can be exported are: PYTHON, EPYTHON,
# PYTHON_SITEDIR. They are described more completely in the eclass
# variable documentation.
_python_export() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl var

	case "${1}" in
		python*|jython*)
			impl=${1/_/.}
			shift
			;;
		pypy|pypy3)
			impl=${1}
			shift
			;;
		*)
			impl=${EPYTHON}
			if [[ -z ${impl} ]]; then
				die "_python_export called without a python implementation and EPYTHON is unset"
			fi
			;;
	esac
	debug-print "${FUNCNAME}: implementation: ${impl}"

	for var; do
		case "${var}" in
			EPYTHON)
				export EPYTHON=${impl}
				debug-print "${FUNCNAME}: EPYTHON = ${EPYTHON}"
				;;
			PYTHON)
				# Under EAPI 7+, this should just use ${BROOT}, but Portage
				# <3.0.50 was buggy, and prefix users need this to update.
				export PYTHON=${BROOT-${EPREFIX}}/usr/bin/${impl}
				if [[ " python jython pypy pypy3 " != *" ${PN} "* ]] \
				&& [[ ! -x ${EPREFIX}/usr/bin/${impl} ]] \
				&& { has prefix-stack ${USE} || has stacked-prefix ${FEATURES} ;} ; then
					# Need to look in build prefix
					if [[ -x ${BROOT-${PORTAGE_OVERRIDE_EPREFIX}}/usr/bin/${impl} ]]; then
						PYTHON=${BROOT-${PORTAGE_OVERRIDE_EPREFIX}}/usr/bin/${impl}
					fi
				fi
				debug-print "${FUNCNAME}: PYTHON = ${PYTHON}"
				;;
			PYTHON_STDLIB)
				[[ -n ${PYTHON} ]] || die "PYTHON needs to be set for ${var} to be exported, or requested before it"
				PYTHON_STDLIB=$(
					"${PYTHON}" - "${EPREFIX}/usr" <<-EOF || die
						import sys, sysconfig
						print(sysconfig.get_path("stdlib", vars={"installed_base": sys.argv[1]}))
					EOF
				)
				export PYTHON_STDLIB
				debug-print "${FUNCNAME}: PYTHON_STDLIB = ${PYTHON_STDLIB}"
				;;
			PYTHON_SITEDIR)
				[[ -n ${PYTHON} ]] || die "PYTHON needs to be set for ${var} to be exported, or requested before it"
				PYTHON_SITEDIR=$(
					"${PYTHON}" - "${EPREFIX}/usr" <<-EOF || die
						import sys, sysconfig
						print(sysconfig.get_path("purelib", vars={"base": sys.argv[1]}))
					EOF
				)
				export PYTHON_SITEDIR
				debug-print "${FUNCNAME}: PYTHON_SITEDIR = ${PYTHON_SITEDIR}"
				;;
			PYTHON_INCLUDEDIR)
				[[ -n ${PYTHON} ]] || die "PYTHON needs to be set for ${var} to be exported, or requested before it"
				PYTHON_INCLUDEDIR=$(
					"${PYTHON}" - "${ESYSROOT}/usr" <<-EOF || die
						import sys, sysconfig
						print(sysconfig.get_path("platinclude", vars={"installed_platbase": sys.argv[1]}))
					EOF
				)
				export PYTHON_INCLUDEDIR
				debug-print "${FUNCNAME}: PYTHON_INCLUDEDIR = ${PYTHON_INCLUDEDIR}"

				# Jython gives a non-existing directory
				if [[ ! -d ${PYTHON_INCLUDEDIR} ]]; then
					die "${impl} does not install any header files!"
				fi
				;;
			PYTHON_LIBPATH)
				[[ -n ${PYTHON} ]] || die "PYTHON needs to be set for ${var} to be exported, or requested before it"
				PYTHON_LIBPATH=$(
					"${PYTHON}" - <<-EOF || die
						import os.path, sysconfig
						print(
							os.path.join(
								sysconfig.get_config_var("LIBDIR"),
								sysconfig.get_config_var("LDLIBRARY"))
							if sysconfig.get_config_var("LDLIBRARY")
							else "")
					EOF
				)
				export PYTHON_LIBPATH
				debug-print "${FUNCNAME}: PYTHON_LIBPATH = ${PYTHON_LIBPATH}"

				if [[ ! ${PYTHON_LIBPATH} ]]; then
					die "${impl} lacks a (usable) dynamic library"
				fi
				;;
			PYTHON_CFLAGS)
				local val

				case "${impl}" in
					python*)
						# python-2.7, python-3.2, etc.
						val=$($(tc-getPKG_CONFIG) --cflags ${impl/n/n-}) || die
						;;
					*)
						die "${impl}: obtaining ${var} not supported"
						;;
				esac

				export PYTHON_CFLAGS=${val}
				debug-print "${FUNCNAME}: PYTHON_CFLAGS = ${PYTHON_CFLAGS}"
				;;
			PYTHON_LIBS)
				local val

				case "${impl}" in
					python*)
						# python3.8+
						val=$($(tc-getPKG_CONFIG) --libs ${impl/n/n-}-embed) || die
						;;
					*)
						die "${impl}: obtaining ${var} not supported"
						;;
				esac

				export PYTHON_LIBS=${val}
				debug-print "${FUNCNAME}: PYTHON_LIBS = ${PYTHON_LIBS}"
				;;
			PYTHON_CONFIG)
				local flags val

				case "${impl}" in
					python*)
						[[ -n ${PYTHON} ]] || die "PYTHON needs to be set for ${var} to be exported, or requested before it"
						flags=$(
							"${PYTHON}" - <<-EOF || die
								import sysconfig
								print(sysconfig.get_config_var("ABIFLAGS")
									or "")
							EOF
						)
						val=${PYTHON}${flags}-config
						;;
					*)
						die "${impl}: obtaining ${var} not supported"
						;;
				esac

				export PYTHON_CONFIG=${val}
				debug-print "${FUNCNAME}: PYTHON_CONFIG = ${PYTHON_CONFIG}"
				;;
			PYTHON_PKG_DEP)
				local d
				case ${impl} in
					python*)
						PYTHON_PKG_DEP="dev-lang/python:${impl#python}"
						;;
					pypy3)
						PYTHON_PKG_DEP="dev-python/${impl}:="
						;;
					*)
						die "Invalid implementation: ${impl}"
				esac

				# use-dep
				if [[ ${PYTHON_REQ_USE} ]]; then
					PYTHON_PKG_DEP+=[${PYTHON_REQ_USE}]
				fi

				export PYTHON_PKG_DEP
				debug-print "${FUNCNAME}: PYTHON_PKG_DEP = ${PYTHON_PKG_DEP}"
				;;
			PYTHON_SCRIPTDIR)
				local dir
				export PYTHON_SCRIPTDIR=${EPREFIX}/usr/lib/python-exec/${impl}
				if [[ " python jython pypy pypy3 " != *" ${PN} "* ]] \
				&& [[ ! -x ${EPREFIX}/usr/bin/${impl} ]] \
				&& { has prefix-stack ${USE} || has stacked-prefix ${FEATURES} ;} ; then
					# Need to look in build prefix
					if [[ -x ${BROOT-${PORTAGE_OVERRIDE_EPREFIX}}/usr/bin/${impl} ]]; then
						PYTHON_SCRIPTDIR=${BROOT-${PORTAGE_OVERRIDE_EPREFIX}}/usr/lib/python-exec/${impl}
					fi
				fi
				debug-print "${FUNCNAME}: PYTHON_SCRIPTDIR = ${PYTHON_SCRIPTDIR}"
				;;
			*)
				die "_python_export: unknown variable ${var}"
		esac
	done
}

# @FUNCTION: python_get_stdlib
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the 'stdlib' path for the given implementation. If no
# implementation is provided, ${EPYTHON} will be used.
python_get_stdlib() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_STDLIB
	echo "${PYTHON_STDLIB}"
}

# @FUNCTION: python_get_sitedir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the 'site-packages' path for the given
# implementation. If no implementation is provided, ${EPYTHON} will
# be used.
python_get_sitedir() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_SITEDIR
	echo "${PYTHON_SITEDIR}"
}

# @FUNCTION: python_get_includedir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the include path for the given implementation. If no
# implementation is provided, ${EPYTHON} will be used.
python_get_includedir() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_INCLUDEDIR
	echo "${PYTHON_INCLUDEDIR}"
}

# @FUNCTION: python_get_library_path
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the Python library path for the given implementation.
# If no implementation is provided, ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only. Use
# in another implementation will result in a fatal failure.
python_get_library_path() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_LIBPATH
	echo "${PYTHON_LIBPATH}"
}

# @FUNCTION: python_get_CFLAGS
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the compiler flags for building against Python,
# for the given implementation. If no implementation is provided,
# ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only.
# It requires Python and pkg-config installed, and therefore proper
# build-time dependencies need be added to the ebuild.
python_get_CFLAGS() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_CFLAGS
	echo "${PYTHON_CFLAGS}"
}

# @FUNCTION: python_get_LIBS
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the compiler flags for linking against Python,
# for the given implementation. If no implementation is provided,
# ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only.
# It requires Python and pkg-config installed, and therefore proper
# build-time dependencies need be added to the ebuild.
python_get_LIBS() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_LIBS
	echo "${PYTHON_LIBS}"
}

# @FUNCTION: python_get_PYTHON_CONFIG
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the PYTHON_CONFIG location for the given
# implementation. If no implementation is provided, ${EPYTHON} will be
# used.
#
# Please note that this function can be used with CPython only.
# It requires Python installed, and therefore proper build-time
# dependencies need be added to the ebuild.
python_get_PYTHON_CONFIG() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_CONFIG
	echo "${PYTHON_CONFIG}"
}

# @FUNCTION: python_get_scriptdir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the script install path for the given
# implementation. If no implementation is provided, ${EPYTHON} will
# be used.
python_get_scriptdir() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_export "${@}" PYTHON_SCRIPTDIR
	echo "${PYTHON_SCRIPTDIR}"
}

# @FUNCTION: python_optimize
# @USAGE: [<directory>...]
# @DESCRIPTION:
# Compile and optimize Python modules in specified directories (absolute
# paths). If no directories are provided, the default system paths
# are used (prepended with ${D}).
python_optimize() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local PYTHON=${PYTHON}
	[[ ${PYTHON} ]] || _python_export PYTHON
	[[ -x ${PYTHON} ]] || die "PYTHON (${PYTHON}) is not executable"

	# default to sys.path
	if [[ ${#} -eq 0 ]]; then
		local f
		while IFS= read -r -d '' f; do
			# 1) accept only absolute paths
			#    (i.e. skip '', '.' or anything like that)
			# 2) skip paths which do not exist
			#    (python2.6 complains about them verbosely)

			if [[ ${f} == /* && -d ${D%/}${f} ]]; then
				set -- "${D%/}${f}" "${@}"
			fi
		done < <(
			"${PYTHON}" - <<-EOF || die
				import sys
				print("".join(x + "\0" for x in sys.path))
			EOF
		)

		debug-print "${FUNCNAME}: using sys.path: ${*/%/;}"
	fi

	local jobs=$(makeopts_jobs)
	local d
	for d; do
		# make sure to get a nice path without //
		local instpath=${d#${D%/}}
		instpath=/${instpath##/}

		einfo "Optimize Python modules for ${instpath}"
		case "${EPYTHON}" in
			python3.8)
				# both levels of optimization are separate since 3.5
				"${PYTHON}" -m compileall -j "${jobs}" -q -f -d "${instpath}" "${d}"
				"${PYTHON}" -O -m compileall -j "${jobs}" -q -f -d "${instpath}" "${d}"
				"${PYTHON}" -OO -m compileall -j "${jobs}" -q -f -d "${instpath}" "${d}"
				;;
			python*|pypy3)
				# Python 3.9+
				"${PYTHON}" -m compileall -j "${jobs}" -o 0 -o 1 -o 2 --hardlink-dupes -q -f -d "${instpath}" "${d}"
				;;
			pypy|jython2.7)
				"${PYTHON}" -m compileall -q -f -d "${instpath}" "${d}"
				;;
			*)
				die "${FUNCNAME}: unexpected EPYTHON=${EPYTHON}"
				;;
		esac
	done
}

# @FUNCTION: python_scriptinto
# @USAGE: <new-path>
# @DESCRIPTION:
# Set the directory to which files passed to python_doexe(),
# python_doscript(), python_newexe() and python_newscript()
# are going to be installed. The new value needs to be relative
# to the installation root (${ED}).
#
# If not set explicitly, the directory defaults to /usr/bin.
#
# Example:
# @CODE
# src_install() {
#   python_scriptinto /usr/sbin
#   python_foreach_impl python_doscript foo
# }
# @CODE
python_scriptinto() {
	debug-print-function ${FUNCNAME} "${@}"

	_PYTHON_SCRIPTROOT=${1}
}

# @FUNCTION: python_doexe
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given executables into the executable install directory,
# for the current Python implementation (${EPYTHON}).
#
# The executable will be wrapped properly for the Python implementation,
# though no shebang mangling will be performed.
python_doexe() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} != install ]] &&
		die "${FUNCNAME} can only be used in src_install"

	local f
	for f; do
		python_newexe "${f}" "${f##*/}"
	done
}

# @FUNCTION: python_newexe
# @USAGE: <path> <new-name>
# @DESCRIPTION:
# Install the given executable into the executable install directory,
# for the current Python implementation (${EPYTHON}).
#
# The executable will be wrapped properly for the Python implementation,
# though no shebang mangling will be performed. It will be renamed
# to <new-name>.
python_newexe() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} != install ]] &&
		die "${FUNCNAME} can only be used in src_install"
	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
	[[ ${#} -eq 2 ]] || die "Usage: ${FUNCNAME} <path> <new-name>"

	local wrapd=${_PYTHON_SCRIPTROOT:-/usr/bin}

	local f=${1}
	local newfn=${2}

	local scriptdir=$(python_get_scriptdir)
	local d=${scriptdir#${EPREFIX}}

	(
		dodir "${wrapd}"
		exeopts -m 0755
		exeinto "${d}"
		newexe "${f}" "${newfn}" || return ${?}
	)

	# install the wrapper
	local dosym=dosym
	[[ ${EAPI} == 7 ]] && dosym=dosym8
	"${dosym}" -r /usr/lib/python-exec/python-exec2 "${wrapd}/${newfn}"

	# don't use this at home, just call python_doscript() instead
	if [[ ${_PYTHON_REWRITE_SHEBANG} ]]; then
		python_fix_shebang -q "${ED%/}/${d}/${newfn}"
	fi
}

# @FUNCTION: python_doscript
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given scripts into the executable install directory,
# for the current Python implementation (${EPYTHON}).
#
# All specified files must start with a 'python' shebang. The shebang
# will be converted, and the files will be wrapped properly
# for the Python implementation.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_doscript ${PN}
# }
# @CODE
python_doscript() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} != install ]] &&
		die "${FUNCNAME} can only be used in src_install"

	local _PYTHON_REWRITE_SHEBANG=1
	python_doexe "${@}"
}

# @FUNCTION: python_newscript
# @USAGE: <path> <new-name>
# @DESCRIPTION:
# Install the given script into the executable install directory
# for the current Python implementation (${EPYTHON}), and name it
# <new-name>.
#
# The file must start with a 'python' shebang. The shebang will be
# converted, and the file will be wrapped properly for the Python
# implementation. It will be renamed to <new-name>.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_newscript foo.py foo
# }
# @CODE
python_newscript() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} != install ]] &&
		die "${FUNCNAME} can only be used in src_install"

	local _PYTHON_REWRITE_SHEBANG=1
	python_newexe "${@}"
}

# @FUNCTION: python_moduleinto
# @USAGE: <new-path>
# @DESCRIPTION:
# Set the Python module install directory for python_domodule().
# The <new-path> can either be an absolute target system path (in which
# case it needs to start with a slash, and ${ED} will be prepended to
# it) or relative to the implementation's site-packages directory
# (then it must not start with a slash). The relative path can be
# specified either using the Python package notation (separated by dots)
# or the directory notation (using slashes).
#
# When not set explicitly, the modules are installed to the top
# site-packages directory.
#
# In the relative case, the exact path is determined directly
# by each python_domodule invocation. Therefore, python_moduleinto
# can be safely called before establishing the Python interpreter and/or
# a single call can be used to set the path correctly for multiple
# implementations, as can be seen in the following example.
#
# Example:
# @CODE
# src_install() {
#   python_moduleinto bar
#   # installs ${PYTHON_SITEDIR}/bar/baz.py
#   python_foreach_impl python_domodule baz.py
# }
# @CODE
python_moduleinto() {
	debug-print-function ${FUNCNAME} "${@}"

	_PYTHON_MODULEROOT=${1}
}

# @FUNCTION: python_domodule
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given modules (or packages) into the current Python module
# installation directory. The list can mention both modules (files)
# and packages (directories). All listed files will be installed
# for all enabled implementations, and compiled afterwards.
#
# The files are installed into ${D} when run in src_install() phase.
# Otherwise, they are installed into ${BUILD_DIR}/install location
# that is suitable for picking up by distutils-r1 in PEP517 mode.
#
# Example:
# @CODE
# src_install() {
#   # (${PN} being a directory)
#   python_foreach_impl python_domodule ${PN}
# }
# @CODE
python_domodule() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local d
	if [[ ${_PYTHON_MODULEROOT} == /* ]]; then
		# absolute path
		d=${_PYTHON_MODULEROOT}
	else
		# relative to site-packages
		local sitedir=$(python_get_sitedir)
		d=${sitedir#${EPREFIX}}/${_PYTHON_MODULEROOT//.//}
	fi

	if [[ ${EBUILD_PHASE} == install ]]; then
		(
			insopts -m 0644
			insinto "${d}"
			doins -r "${@}" || return ${?}
		)
		python_optimize "${ED%/}/${d}"
	elif [[ -n ${BUILD_DIR} ]]; then
		local dest=${BUILD_DIR}/install${EPREFIX}/${d}
		mkdir -p "${dest}" || die
		cp -pR "${@}" "${dest}/" || die
		(
			cd "${dest}" &&
			chmod -R a+rX "${@##*/}"
		) || die
	else
		die "${FUNCNAME} can only be used in src_install or with BUILD_DIR set"
	fi
}

# @FUNCTION: python_doheader
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given headers into the implementation-specific include
# directory. This function is unconditionally recursive, i.e. you can
# pass directories instead of files.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_doheader foo.h bar.h
# }
# @CODE
python_doheader() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} != install ]] &&
		die "${FUNCNAME} can only be used in src_install"
	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local includedir=$(python_get_includedir)
	local d=${includedir#${ESYSROOT}}

	(
		insopts -m 0644
		insinto "${d}"
		doins -r "${@}" || return ${?}
	)
}

# @FUNCTION: _python_wrapper_setup
# @USAGE: [<path> [<impl>]]
# @INTERNAL
# @DESCRIPTION:
# Create proper 'python' executable and pkg-config wrappers
# (if available) in the directory named by <path>. Set up PATH
# and PKG_CONFIG_PATH appropriately. <path> defaults to ${T}/${EPYTHON}.
#
# The wrappers will be created for implementation named by <impl>,
# or for one named by ${EPYTHON} if no <impl> passed.
#
# If the named directory contains a python symlink already, it will
# be assumed to contain proper wrappers already and only environment
# setup will be done. If wrapper update is requested, the directory
# shall be removed first.
_python_wrapper_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	local workdir=${1:-${T}/${EPYTHON}}
	local impl=${2:-${EPYTHON}}

	[[ ${workdir} ]] || die "${FUNCNAME}: no workdir specified."
	[[ ${impl} ]] || die "${FUNCNAME}: no impl nor EPYTHON specified."

	if [[ ! -x ${workdir}/bin/python ]]; then
		mkdir -p "${workdir}"/{bin,pkgconfig} || die

		# Clean up, in case we were supposed to do a cheap update.
		rm -f "${workdir}"/bin/python{,2,3}{,-config} || die
		rm -f "${workdir}"/bin/2to3 || die
		rm -f "${workdir}"/pkgconfig/python{2,3}{,-embed}.pc || die

		local EPYTHON PYTHON
		_python_export "${impl}" EPYTHON PYTHON

		# Python interpreter
		# note: we don't use symlinks because python likes to do some
		# symlink reading magic that breaks stuff
		# https://bugs.gentoo.org/show_bug.cgi?id=555752
		cat > "${workdir}/bin/python" <<-_EOF_ || die
			#!/bin/sh
			exec "${PYTHON}" "\${@}"
		_EOF_
		cp "${workdir}/bin/python" "${workdir}/bin/python3" || die
		chmod +x "${workdir}/bin/python" "${workdir}/bin/python3" || die

		local nonsupp=( python2 python2-config )

		# CPython-specific
		if [[ ${EPYTHON} == python* ]]; then
			cat > "${workdir}/bin/python-config" <<-_EOF_ || die
				#!/bin/sh
				exec "${PYTHON}-config" "\${@}"
			_EOF_
			cp "${workdir}/bin/python-config" \
				"${workdir}/bin/python3-config" || die
			chmod +x "${workdir}/bin/python-config" \
				"${workdir}/bin/python3-config" || die

			# Python 2.6+.
			ln -s "${PYTHON/python/2to3-}" "${workdir}"/bin/2to3 || die

			# Python 2.7+.
			ln -s "${EPREFIX}"/usr/$(get_libdir)/pkgconfig/${EPYTHON/n/n-}.pc \
				"${workdir}"/pkgconfig/python3.pc || die

			# Python 3.8+.
			ln -s "${EPREFIX}"/usr/$(get_libdir)/pkgconfig/${EPYTHON/n/n-}-embed.pc \
				"${workdir}"/pkgconfig/python3-embed.pc || die
		else
			nonsupp+=( 2to3 python-config python3-config )
		fi

		local x
		for x in "${nonsupp[@]}"; do
			cat >"${workdir}"/bin/${x} <<-_EOF_ || die
				#!/bin/sh
				echo "${ECLASS}: ${FUNCNAME}: ${x} is not supported by ${EPYTHON} (PYTHON_COMPAT)" >&2
				exit 127
			_EOF_
			chmod +x "${workdir}"/bin/${x} || die
		done
	fi

	# Now, set the environment.
	# But note that ${workdir} may be shared with something else,
	# and thus already on top of PATH.
	if [[ ${PATH##:*} != ${workdir}/bin ]]; then
		PATH=${workdir}/bin${PATH:+:${PATH}}
	fi
	if [[ ${PKG_CONFIG_PATH##:*} != ${workdir}/pkgconfig ]]; then
		PKG_CONFIG_PATH=${workdir}/pkgconfig${PKG_CONFIG_PATH:+:${PKG_CONFIG_PATH}}
	fi
	export PATH PKG_CONFIG_PATH
}

# @FUNCTION: python_fix_shebang
# @USAGE: [-f|--force] [-q|--quiet] <path>...
# @DESCRIPTION:
# Replace the shebang in Python scripts with the full path
# to the current Python implementation (PYTHON, including EPREFIX).
# If a directory is passed, works recursively on all Python scripts
# found inside the directory tree.
#
# Only files having a Python shebang (a path to any known Python
# interpreter, optionally preceded by env(1) invocation) will
# be processed.  Files with any other shebang will either be skipped
# silently when a directory was passed, or an error will be reported
# for any files without Python shebangs specified explicitly.
#
# Shebangs that are compatible with the current Python version will be
# mangled unconditionally.  Incompatible shebangs will cause a fatal
# error, unless --force is specified.
#
# --force causes the function to replace shebangs with incompatible
# Python version (but not non-Python shebangs).  --quiet causes
# the function not to list modified files verbosely.
python_fix_shebang() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die "${FUNCNAME}: EPYTHON unset (pkg_setup not called?)"

	local force quiet
	while [[ ${@} ]]; do
		case "${1}" in
			-f|--force) force=1; shift;;
			-q|--quiet) quiet=1; shift;;
			--) shift; break;;
			*) break;;
		esac
	done

	[[ ${1} ]] || die "${FUNCNAME}: no paths given"

	local path f
	for path; do
		local any_fixed is_recursive

		[[ -d ${path} ]] && is_recursive=1

		while IFS= read -r -d '' f; do
			local shebang i
			local error= match=

			# note: we can't ||die here since read will fail if file
			# has no newline characters
			IFS= read -r shebang <"${f}"

			# First, check if it's shebang at all...
			if [[ ${shebang} == '#!'* ]]; then
				local split_shebang=()
				read -r -a split_shebang <<<${shebang#"#!"} || die

				local in_path=${split_shebang[0]}
				local from='^#! *[^ ]*'
				# if the first component is env(1), skip it
				if [[ ${in_path} == */env ]]; then
					in_path=${split_shebang[1]}
					from+=' *[^ ]*'
				fi

				case ${in_path##*/} in
					"${EPYTHON}")
						match=1
						;;
					python|python3)
						match=1
						;;
					python2|python[23].[0-9]|python3.[1-9][0-9]|pypy|pypy3|jython[23].[0-9])
						# Explicit mismatch.
						match=1
						error=1
						;;
				esac
			fi

			# disregard mismatches in force mode
			[[ ${force} ]] && error=

			if [[ ! ${match} ]]; then
				# Non-Python shebang. Allowed in recursive mode,
				# disallowed when specifying file explicitly.
				[[ ${is_recursive} ]] && continue
				error=1
			fi

			if [[ ! ${quiet} ]]; then
				einfo "Fixing shebang in ${f#${D%/}}."
			fi

			if [[ ! ${error} ]]; then
				debug-print "${FUNCNAME}: in file ${f#${D%/}}"
				debug-print "${FUNCNAME}: rewriting shebang: ${shebang}"
				sed -i -e "1s@${from}@#!${EPREFIX}/usr/bin/${EPYTHON}@" "${f}" || die
				any_fixed=1
			else
				eerror "The file has incompatible shebang:"
				eerror "  file: ${f#${D%/}}"
				eerror "  current shebang: ${shebang}"
				eerror "  requested impl: ${EPYTHON}"
				die "${FUNCNAME}: conversion of incompatible shebang requested"
			fi
		done < <(find -H "${path}" -type f -print0 || die)

		if [[ ! ${any_fixed} ]]; then
			eerror "QA error: ${FUNCNAME}, ${path#${D%/}} did not match any fixable files."
			eerror "There are no Python files in specified directory."
			die "${FUNCNAME} did not match any fixable files"
		fi
	done
}

# @FUNCTION: _python_check_locale_sanity
# @USAGE: <locale>
# @RETURN: 0 if sane, 1 otherwise
# @INTERNAL
# @DESCRIPTION:
# Check whether the specified locale sanely maps between lowercase
# and uppercase ASCII characters.
_python_check_locale_sanity() {
	local -x LC_ALL=${1}
	local IFS=

	local lc=( {a..z} )
	local uc=( {A..Z} )
	local input="${lc[*]}${uc[*]}"

	local output=$(tr '[:lower:][:upper:]' '[:upper:][:lower:]' <<<"${input}")
	[[ ${output} == "${uc[*]}${lc[*]}" ]]
}

# @FUNCTION: python_export_utf8_locale
# @RETURN: 0 on success, 1 on failure.
# @DESCRIPTION:
# Attempts to export a usable UTF-8 locale in the LC_CTYPE variable. Does
# nothing if LC_ALL is defined, or if the current locale uses a UTF-8 charmap.
# This may be used to work around the quirky open() behavior of python3.
python_export_utf8_locale() {
	debug-print-function ${FUNCNAME} "${@}"

	# If the locale program isn't available, just return.
	type locale &>/dev/null || return 0

	if [[ $(locale charmap) != UTF-8 ]]; then
		# Try English first, then everything else.
		local lang locales="C.UTF-8 en_US.UTF-8 en_GB.UTF-8 $(locale -a)"

		for lang in ${locales}; do
			if [[ $(LC_ALL=${lang} locale charmap 2>/dev/null) == UTF-8 ]]; then
				if _python_check_locale_sanity "${lang}"; then
					export LC_CTYPE=${lang}
					if [[ -n ${LC_ALL} ]]; then
						export LC_NUMERIC=${LC_ALL}
						export LC_TIME=${LC_ALL}
						export LC_COLLATE=${LC_ALL}
						export LC_MONETARY=${LC_ALL}
						export LC_MESSAGES=${LC_ALL}
						export LC_PAPER=${LC_ALL}
						export LC_NAME=${LC_ALL}
						export LC_ADDRESS=${LC_ALL}
						export LC_TELEPHONE=${LC_ALL}
						export LC_MEASUREMENT=${LC_ALL}
						export LC_IDENTIFICATION=${LC_ALL}
						export LC_ALL=
					fi
					return 0
				fi
			fi
		done

		ewarn "Could not find a UTF-8 locale. This may trigger build failures in"
		ewarn "some python packages. Please ensure that a UTF-8 locale is listed in"
		ewarn "/etc/locale.gen and run locale-gen."
		return 1
	fi

	return 0
}

# @FUNCTION: build_sphinx
# @USAGE: <directory>
# @DESCRIPTION:
# Build HTML documentation using dev-python/sphinx in the specified
# <directory>.  Takes care of disabling Intersphinx and appending
# to HTML_DOCS.
#
# If <directory> is relative to the current directory, care needs
# to be taken to run einstalldocs from the same directory
# (usually ${S}).
build_sphinx() {
	debug-print-function ${FUNCNAME} "${@}"
	[[ ${#} -eq 1 ]] || die "${FUNCNAME} takes 1 arg: <directory>"

	local dir=${1}

	sed -i -e 's:^intersphinx_mapping:disabled_&:' \
		"${dir}"/conf.py || die
	# 1. not all packages include the Makefile in pypi tarball,
	# so we call sphinx-build directly
	# 2. if autodoc is used, we need to call sphinx via EPYTHON,
	# to ensure that PEP 517 venv is respected
	# 3. if autodoc is not used, then sphinx might not be installed
	# for the current impl, so we need a fallback to sphinx-build
	local command=( "${EPYTHON}" -m sphinx.cmd.build )
	if ! "${EPYTHON}" -c "import sphinx.cmd.build" 2>/dev/null; then
		command=( sphinx-build )
	fi
	command+=(
		-b html
		-d "${dir}"/_build/doctrees
		"${dir}"
		"${dir}"/_build/html
	)
	echo "${command[@]}" >&2
	"${command[@]}" || die

	HTML_DOCS+=( "${dir}/_build/html/." )
}

# @FUNCTION: _python_check_EPYTHON
# @INTERNAL
# @DESCRIPTION:
# Check if EPYTHON is set, die if not.
_python_check_EPYTHON() {
	if [[ -z ${EPYTHON} ]]; then
		die "EPYTHON unset, invalid call context"
	fi
}

# @FUNCTION: _python_check_occluded_packages
# @INTERNAL
# @DESCRIPTION:
# Check if the current directory does not contain any incomplete
# package sources that would block installed packages from being used
# (and effectively e.g. make it impossible to load compiled extensions).
_python_check_occluded_packages() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ -z ${BUILD_DIR} || ! -d ${BUILD_DIR}/install ]] && return

	local sitedir="${BUILD_DIR}/install$(python_get_sitedir)"
	# avoid unnecessarily checking if we are inside install dir
	[[ ${sitedir} -ef . ]] && return

	local f fn diff l
	for f in "${sitedir}"/*/; do
		f=${f%/}
		fn=${f##*/}

		# skip metadata directories
		[[ ${fn} == *.dist-info || ${fn} == *.egg-info ]] && continue

		if [[ -d ${fn} ]]; then
			diff=$(
				comm -1 -3 <(
					find "${fn}" -type f -not -path '*/__pycache__/*' |
						sort
					assert
				) <(
					cd "${sitedir}" &&
						find "${fn}" -type f -not -path '*/__pycache__/*' |
						sort
					assert
				)
			)

			if [[ -n ${diff} ]]; then
				eqawarn "The directory ${fn} occludes package installed for ${EPYTHON}."
				eqawarn "The installed package includes additional files:"
				eqawarn
				while IFS= read -r l; do
					eqawarn "    ${l}"
				done <<<"${diff}"
				eqawarn

				if [[ ! ${_PYTHON_WARNED_OCCLUDED_PACKAGES} ]]; then
					eqawarn "For more information on occluded packages, please see:"
					eqawarn "https://projects.gentoo.org/python/guide/test.html#importerrors-for-c-extensions"
					_PYTHON_WARNED_OCCLUDED_PACKAGES=1
				fi
			fi
		fi
	done
}

# @VARIABLE: EPYTEST_DESELECT
# @DEFAULT_UNSET
# @DESCRIPTION:
# Specifies an array of tests to be deselected via pytest's --deselect
# parameter, when calling epytest.  The list can include file paths,
# specific test functions or parametrized test invocations.
#
# Note that the listed files will still be subject to collection,
# i.e. modules imported in global scope will need to be available.
# If this is undesirable, EPYTEST_IGNORE can be used instead.

# @VARIABLE: EPYTEST_IGNORE
# @DEFAULT_UNSET
# @DESCRIPTION:
# Specifies an array of paths to be ignored via pytest's --ignore
# parameter, when calling epytest.  The listed files will be entirely
# skipped from test collection.

# @ECLASS_VARIABLE: EPYTEST_TIMEOUT
# @DEFAULT_UNSET
# @DESCRIPTION:
# If set to a non-empty value, enables pytest-timeout plugin and sets
# test timeout to the specified value.  This variable can be either set
# in ebuilds that are known to hang, or by user to prevent hangs
# in automated test environments.  If this variable is set prior
# to calling distutils_enable_tests in distutils-r1, a test dependency
# on dev-python/pytest-timeout is added automatically.

# @ECLASS_VARIABLE: EPYTEST_XDIST
# @DEFAULT_UNSET
# @DESCRIPTION:
# If set to a non-empty value, enables running tests in parallel
# via pytest-xdist plugin.  If this variable is set prior to calling
# distutils_enable_tests in distutils-r1, a test dependency
# on dev-python/pytest-xdist is added automatically.

# @ECLASS_VARIABLE: EPYTEST_JOBS
# @USER_VARIABLE
# @DEFAULT_UNSET
# @DESCRIPTION:
# Specifies the number of jobs for parallel (pytest-xdist) test runs.
# When unset, defaults to -j from MAKEOPTS, or the current nproc.

# @ECLASS_VARIABLE: EPYTEST_FLAGS
# @USER_VARIABLE
# @DEFAULT_UNSET
# @DESCRIPTION:
# Additional flags to pass to pytest.  This is intended to be set
# in the environment when debugging packages (options such as -x or -s
# are useful here), rather than globally.  It must not be set
# in ebuilds.

# @FUNCTION: epytest
# @USAGE: [<args>...]
# @DESCRIPTION:
# Run pytest, passing the standard set of pytest options, then
# --deselect and --ignore options based on EPYTEST_DESELECT
# and EPYTEST_IGNORE, then user-specified options.
#
# This command dies on failure and respects nonfatal.
epytest() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_check_EPYTHON
	_python_check_occluded_packages

	local color=yes
	[[ ${NO_COLOR} ]] && color=no

	local args=(
		# verbose progress reporting and tracebacks
		-vv
		# list all non-passed tests in the summary for convenience
		# (includes failures, skips, xfails...)
		-ra
		# print local variables in tracebacks, useful for debugging
		-l
		# override filterwarnings=error, we do not really want -Werror
		# for end users, as it tends to fail on new warnings from deps
		-Wdefault
		# however, do error out if the package failed to load
		# an appropriate async plugin
		-Werror::pytest.PytestUnhandledCoroutineWarning
		# override color output
		"--color=${color}"
		# count is more precise when we're dealing with a large number
		# of tests
		-o console_output_style=count
		# minimize the temporary directory retention, the test suites
		# of some packages can grow them pretty large and normally
		# we don't need to preserve them
		-o tmp_path_retention_count=0
		-o tmp_path_retention_policy=failed
	)

	if [[ ! ${PYTEST_DISABLE_PLUGIN_AUTOLOAD} ]]; then
		args+=(
			# disable the undesirable-dependency plugins by default to
			# trigger missing argument strips.  strip options that require
			# them from config files.  enable them explicitly via "-p ..."
			# if you *really* need them.
			-p no:cov
			-p no:flake8
			-p no:flakes
			-p no:pylint
			# sterilize pytest-markdown as it runs code snippets from all
			# *.md files found without any warning
			-p no:markdown
			# pytest-sugar undoes everything that's good about pytest output
			# and makes it hard to read logs
			-p no:sugar
			# pytest-xvfb automatically spawns Xvfb for every test suite,
			# effectively forcing it even when we'd prefer the tests
			# not to have DISPLAY at all, causing crashes sometimes
			# and causing us to miss missing virtualx usage
			-p no:xvfb
			# intrusive packages that break random test suites
			-p no:pytest-describe
			-p no:plus
			-p no:tavern
			# does something to logging
			-p no:salt-factories
		)
	fi

	if [[ -n ${EPYTEST_TIMEOUT} ]]; then
		if [[ ${PYTEST_PLUGINS} != *pytest_timeout* ]]; then
			args+=(
				-p timeout
			)
		fi

		args+=(
			"--timeout=${EPYTEST_TIMEOUT}"
		)
	fi

	if [[ ${EPYTEST_XDIST} ]]; then
		local jobs=${EPYTEST_JOBS:-$(makeopts_jobs)}
		if [[ ${jobs} -gt 1 ]]; then
			if [[ ${PYTEST_PLUGINS} != *xdist.plugin* ]]; then
				args+=(
					# explicitly enable the plugin, in case the ebuild was
					# using PYTEST_DISABLE_PLUGIN_AUTOLOAD=1
					-p xdist
				)
			fi
			args+=(
				-n "${jobs}"
				# worksteal ensures that workers don't end up idle when heavy
				# jobs are unevenly distributed
				--dist=worksteal
			)
		fi
	fi

	local x
	for x in "${EPYTEST_DESELECT[@]}"; do
		args+=( --deselect "${x}" )
	done
	for x in "${EPYTEST_IGNORE[@]}"; do
		args+=( --ignore "${x}" )
	done
	set -- "${EPYTHON}" -m pytest "${args[@]}" "${@}" ${EPYTEST_FLAGS}

	echo "${@}" >&2
	"${@}"
	local ret=${?}

	# remove common temporary directories left over by pytest plugins
	rm -rf .hypothesis .pytest_cache || die
	# pytest plugins create additional .pyc files while testing
	# see e.g. https://bugs.gentoo.org/847235
	if [[ -n ${BUILD_DIR} && -d ${BUILD_DIR} ]]; then
		find "${BUILD_DIR}" -name '*-pytest-*.pyc' -delete || die
	fi

	[[ ${ret} -ne 0 ]] && die -n "pytest failed with ${EPYTHON}"
	return ${ret}
}

# @FUNCTION: eunittest
# @USAGE: [<args>...]
# @DESCRIPTION:
# Run unit tests using dev-python/unittest-or-fail, passing the standard
# set of options, followed by user-specified options.
#
# This command dies on failure and respects nonfatal.
eunittest() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_check_EPYTHON
	_python_check_occluded_packages

	# unittest fails with "no tests" correctly since Python 3.12
	local runner=unittest
	if _python_impl_matches "${EPYTHON}" 3.{9..11}; then
		runner=unittest_or_fail
	fi
	set -- "${EPYTHON}" -m "${runner}" discover -v "${@}"

	echo "${@}" >&2
	"${@}" || die -n "Tests failed with ${EPYTHON}"
	return ${?}
}

# @FUNCTION: _python_run_check_deps
# @INTERNAL
# @USAGE: <impl>
# @DESCRIPTION:
# Verify whether <impl> is an acceptable choice to run any-r1 style
# code.  Checks whether the interpreter is installed, runs
# python_check_deps() if declared.
_python_run_check_deps() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl=${1}

	einfo "Checking whether ${impl} is suitable ..."

	local PYTHON_PKG_DEP
	_python_export "${impl}" PYTHON_PKG_DEP
	ebegin "  ${PYTHON_PKG_DEP}"
	has_version -b "${PYTHON_PKG_DEP}"
	eend ${?} || return 1
	declare -f python_check_deps >/dev/null || return 0

	local PYTHON_USEDEP="python_targets_${impl}(-)"
	local PYTHON_SINGLE_USEDEP="python_single_target_${impl}(-)"
	ebegin "  python_check_deps"
	python_check_deps
	eend ${?}
}

# @FUNCTION: python_has_version
# @USAGE: [-b|-d|-r] <atom>...
# @DESCRIPTION:
# A convenience wrapper for has_version() with verbose output and better
# defaults for use in python_check_deps().
#
# The wrapper accepts -b/-d/-r options to indicate the root to perform
# the lookup on.  Unlike has_version, the default is -b.
#
# The wrapper accepts multiple package specifications.  For the check
# to succeed, *all* specified atoms must match.
python_has_version() {
	debug-print-function ${FUNCNAME} "${@}"

	local root_arg=( -b )
	case ${1} in
		-b|-d|-r)
			root_arg=( "${1}" )
			shift
			;;
	esac

	local pkg
	for pkg; do
		ebegin "    ${pkg}"
		has_version "${root_arg[@]}" "${pkg}"
		eend ${?} || return
	done

	return 0
}

# @FUNCTION: _python_sanity_checks
# @INTERNAL
# @DESCRIPTION:
# Perform additional environment sanity checks.
_python_sanity_checks() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${_PYTHON_SANITY_CHECKED} ]] && return

	if [[ -v PYTHONPATH ]]; then
		local x paths=()
		mapfile -d ':' -t paths <<<${PYTHONPATH}

		for x in "${paths[@]}"; do
			if [[ ${x} != /* ]]; then
				eerror "Relative path found in PYTHONPATH:"
				eerror
				eerror "  PYTHONPATH=${PYTHONPATH@Q}"
				eerror
				eerror "This is guaranteed to cause random breakage.  Please make sure that"
				eerror "your PYTHONPATH contains absolute paths only (and only if necessary)."
				eerror "Note that empty values (including ':' at either end and an empty"
				eerror "PYTHONPATH) count as the current directory.  If no PYTHONPATH"
				eerror "is intended, it needs to be unset instead."
				die "Relative paths in PYTHONPATH are forbidden: ${x@Q}"
			fi
		done

		elog "PYTHONPATH=${PYTHONPATH@Q}"
	fi

	_PYTHON_SANITY_CHECKED=1
}

fi