#!/bin/bash
errors_terminate=$2

# Usage of %_python_bytecompile_extra is not allowed anymore
# See: https://fedoraproject.org/wiki/Changes/No_more_automagic_Python_bytecompilation_phase_3
# Therefore $1 ($default_python) is not needed and is invoked with "" by default.
# $default_python stays in the arguments for backward compatibility and $extra for the following check:
extra=$3
if [ 0$extra -eq 1 ]; then
    echo -e "%_python_bytecompile_extra is discontinued, use %py_byte_compile instead.\nSee: https://fedoraproject.org/wiki/Changes/No_more_automagic_Python_bytecompilation_phase_3" >/dev/stderr
    exit 1
fi

compileall_flags="$4"

# If using normal root, avoid changing anything.
if [ -z "$RPM_BUILD_ROOT" -o "$RPM_BUILD_ROOT" = "/" ]; then
	exit 0
fi

# This function clamps the source mtime, see https://fedoraproject.org/wiki/Changes/ReproducibleBuildsClampMtimes
function python_clamp_source_mtime()
{
    local _=$1
    local python_binary=$2
    local _=$3
    local python_libdir="$4"
    PYTHONPATH=/usr/lib/rpm/redhat/ $python_binary -B -m clamp_source_mtime -q "$python_libdir"
}

# This function now implements Python byte-compilation in three different ways:
# Python >= 3.4 and < 3.9 uses a new module compileall2 - https://github.com/fedora-python/compileall2
# In Python >= 3.9, compileall2 was merged back to standard library (compileall) so we can use it directly again.
# Python < 3.4 (inc. Python 2) uses compileall module from stdlib with some hacks
function python_bytecompile()
{
    local options=$1
    local python_binary=$2
    local exclude=$3
    local python_libdir="$4"
    local compileall_flags="$5"

    python_version=$($python_binary -c "import sys; sys.stdout.write('{0.major}{0.minor}'.format(sys.version_info))")

    #
    # Python 3.4 and higher
    #
    if [ "$python_version" -ge 34 ]; then

        # We compile all opt levels in one go: only when $options is empty.
        if [ -n "$options" ]; then
            return
        fi

        if [ "$python_version" -ge 39 ]; then
            # For Pyhon 3.9+, use the standard library
            compileall_module=compileall
        else
            # For older Pythons, use compileall2
            compileall_module=compileall2
        fi

        if [ "$python_version" -ge 37 ]; then
            # Force the TIMESTAMP invalidation mode
            invalidation_option=--invalidation-mode=timestamp
        else
            # For older Pythons, the option does not exist
            # as the invalidation is always based on size+mtime
            invalidation_option=
        fi

        [ ! -z $exclude ] && exclude="-x '$exclude'"

        # PYTHONPATH is needed for compileall2, but doesn't hurt for the stdlib
        # -o 0 -o 1 are the optimization levels
        # -q disables verbose output
        # -f forces the process to overwrite existing compiled files
        # -x excludes paths defined by regex
        # -e excludes symbolic links pointing outside the build root
        # -x and -e together implements the same functionality as the Filter class below
        # -s strips $RPM_BUILD_ROOT from the path
        # -p prepends the leading slash to the path to make it absolute
        PYTHONPATH=/usr/lib/rpm/redhat/ $python_binary -B -m $compileall_module $compileall_flags -o 0 -o 1 -q -f $exclude -s "$RPM_BUILD_ROOT" -p / --hardlink-dupes $invalidation_option -e "$RPM_BUILD_ROOT" "$python_libdir"

    else
#
# Python 3.3 and lower (incl. Python 2)
#

local real_libdir=${python_libdir/$RPM_BUILD_ROOT/}

cat << EOF | $python_binary $options
import compileall, sys, os, re

python_libdir = "$python_libdir"
depth = sys.getrecursionlimit()
real_libdir = "$real_libdir"
build_root = "$RPM_BUILD_ROOT"
exclude = r"$exclude"

class Filter:
    def search(self, path):
        ret = not os.path.realpath(path).startswith(build_root)
        if exclude:
            ret = ret or re.search(exclude, path)
        return ret

sys.exit(not compileall.compile_dir(python_libdir, depth, real_libdir, force=1, rx=Filter(), quiet=1))
EOF

fi
}

# .pyc/.pyo files embed a "magic" value, identifying the ABI version of Python
# bytecode that they are for.
#
# The files below RPM_BUILD_ROOT could be targeting multiple versions of
# python (e.g. a single build that emits several subpackages e.g. a
# python26-foo subpackage, a python31-foo subpackage etc)
#
# Support this by assuming that below each /usr/lib/python$VERSION/, all
# .pyc/.pyo files are to be compiled for /usr/bin/python$VERSION.
#
# For example, below /usr/lib/python2.6/, we're targeting /usr/bin/python2.6
# and below /usr/lib/python3.1/, we're targeting /usr/bin/python3.1

# Disable Python hash seed randomization
# This should help with byte-compilation reproducibility: https://bugzilla.redhat.com/show_bug.cgi?id=1686078
# Python 3.11+ no longer needs this: https://github.com/python/cpython/pull/27926 (but we support older Pythons as well)
export PYTHONHASHSEED=0

shopt -s nullglob
find "$RPM_BUILD_ROOT" -type d -print0|grep -z -E "/(usr|app)/lib(64)?/python[0-9]\.[0-9]+$" | while read -d "" python_libdir;
do
	python_binary=$(basename "$python_libdir")
	echo "Bytecompiling .py files below $python_libdir using $python_binary"

	# Generate normal (.pyc) byte-compiled files.
	python_clamp_source_mtime "" "$python_binary" "" "$python_libdir" ""
	if [ $? -ne 0 -a 0$errors_terminate -ne 0 ]; then
		# One or more of the files had inaccessible mtime
		exit 1
	fi
	python_bytecompile "" "$python_binary" "" "$python_libdir" "$compileall_flags"
	if [ $? -ne 0 -a 0$errors_terminate -ne 0 ]; then
		# One or more of the files had a syntax error
		exit 1
	fi

	# Generate optimized (.pyo) byte-compiled files.
	# N.B. For Python 3.4+, this call does nothing
	python_bytecompile "-O" "$python_binary" "" "$python_libdir" "$compileall_flags"
	if [ $? -ne 0 -a 0$errors_terminate -ne 0 ]; then
		# One or more of the files had a syntax error
		exit 1
	fi
done