view hgeditor @ 35987:6010fe1da619

wireprotoserver: document and improve the httplib workaround

This workaround dates all the way back to a42d27bc809d in 2008.
The code is esoteric enough to warrant an inline explanation.
So I've added one.

At the time the code was written, the only wire protocol command
that accepted an HTTP request body was "unbundle." In the years
since, we've grown the ability to accept command arguments via
HTTP POST requests. So, the code has been changed to apply the
httplib workaround to all HTTP POST requests.

While staring at this code, I realized that the HTTP response
body in case of error is always the same. And, it appears to
mimic the behavior of a failed call to the "unbundle" command.
Since we can hit this code path on theoretically any protocol
request (since self.check_perm accepts custom auth checking
functions which may raise), I'm having a hard time believing
that clients react well to an "unbundle" response payload on
any wire protocol command. I wouldn't be surprised if our test
coverage for this feature only covers HTTP POST calls to
"unbundle." In other words, the experimental support for sending
arguments via HTTP POST request bodies may result in badness on
the client. Something to investigate another time perhaps...

Differential Revision: https://phab.mercurial-scm.org/D2064

#!/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 $?