hgeditor

cext: use sys.executable instead of deprecated Py_GetProgramFullPath

Fix warning with Python 3.13:

    mercurial/cext/parsers.c: In function 'check_python_version':
    mercurial/cext/parsers.c:1243:30: warning: 'Py_GetProgramFullPath' is deprecated [-Wdeprecated-declarations]
     1243 |                              Py_GetProgramFullPath());
          |                              ^~~~~~~~~~~~~~~~~~~~~
    In file included from /usr/include/python3.13/Python.h:119,
                     from mercurial/cext/parsers.c:11:
    /usr/include/python3.13/pylifecycle.h:43:43: note: declared here
       43 | Py_DEPRECATED(3.13) PyAPI_FUNC(wchar_t *) Py_GetProgramFullPath(void);
          |                                           ^~~~~~~~~~~~~~~~~~~~~

At this point in time, the PyConfig struct memory has been released and the PyConfig API can't be used.

https://docs.python.org/3.13/c-api/init.html#c.Py_GetProgramFullPath recommands
using sys.executable instead. Let's assume that will work in all versions.

It would perhaps be better to use PySys_GetObject, but I prefer to stay
consistent with how the same function is retrieving sys.hexversion.

#!/bin/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while committing.

# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
    "")
        EDITOR="vi"
        ;;
    emacs)
        EDITOR="$EDITOR -nw"
        ;;
    gvim|vim)
        EDITOR="$EDITOR -f -o"
        ;;
esac


HGTMP=""
cleanup_exit() {
    rm -rf "$HGTMP"
}

# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" HUP INT QUIT ABRT TERM

HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX)
[ x$HGTMP != x -a -d $HGTMP ] || {
  echo "Could not create temporary directory! Exiting." 1>&2
  exit 1
}

(
    grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
        "$HG" diff "$changed" >> "$HGTMP/diff"
    done
)

cat "$1" > "$HGTMP/msg"

MD5=$(which md5sum 2>/dev/null) || \
    MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
    $EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
    $EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)

mv "$HGTMP/msg" "$1"

exit $?