feat(engine): retire a broadcast with coord-send --retract

Nothing could remove a message from _broadcast/inbox/. coord-done is
directed-only and never touches the broadcast queue, so the backlog could
only grow: every new repo received the entire standing history at its first
session, including announcements that had since become false.

--retract <filename> archives the message into _broadcast/archive/, so no
future repo is served it. Three deliberate limits, all pinned by tests:

- Un-send, not recall. Repos that already received it keep it;
  _broadcast/seen/ is delivery history and is left untouched.
- Only the sender may retract (from: must match the repo identity). --from
  overrides it, as everywhere else in the engine, which makes the check an
  accident guard rather than a security boundary.
- Nothing is deleted, mirroring coord-done. Retracting twice is a no-op.

The branch runs before every send-side validation and before the stdin body
read, since a retract carries no subject and no body.

Selftest 70 -> 82 (new section 19). Also fixes two README defects the
feature exposed: the install command still named coord@ after the v0.3.0
rename, and the docs advised pruning _broadcast/inbox/ by hand, which
contradicted the rule that the script owns mailbox files.
This commit is contained in:
Kjell Tore Guttormsen 2026-07-25 15:11:47 +02:00
commit 316b8acdd2
8 changed files with 184 additions and 15 deletions

View file

@ -235,6 +235,49 @@ printf '%s' "$aerr" | grep -q 'unknown argument: --bogus-flag'; check "inbox: un
aout="$("$INBOX" --repo argrepo --bogus-flag 2>/dev/null)"; rc=$?
[ "$rc" -eq 0 ] && printf '%s' "$aout" | grep -q 'ARG-BODY'; check "inbox: unknown argument still reads the inbox and exits 0" $?
# 19. A broadcast can be retired. Without this, the broadcast backlog grows
# monotonically: every NEW repo receives the whole history at its first session,
# including announcements that have since become false. Retract is sender-side
# ("un-send"), archives rather than deletes, and is NOT recall - repos that
# already received the message keep it. Every invocation reads from /dev/null so
# a regression that falls through to the stdin body read fails instead of hanging.
"$SEND" --broadcast --from retractor --subject "oops" --message "RETRACT-ME-BODY" >/dev/null
rbase="$(basename "$(ls "$CLAUDE_COORD_DIR"/_broadcast/inbox/*-from-retractor.md 2>/dev/null | head -1)")"
"$SEND" --broadcast --from keeper --subject "keep" --message "KEEP-BC-BODY" >/dev/null
nr="$("$SEND" --retract "$rbase" --from someone-else </dev/null 2>&1)"; rc=$?
[ "$rc" -eq 2 ] && printf '%s' "$nr" | grep -q 'sent by retractor'; check "retract by a non-sender is refused" $?
[ -e "$CLAUDE_COORD_DIR/_broadcast/inbox/$rbase" ]; check "refused retract leaves the broadcast pending" $?
vo="$("$SEND" --retract </dev/null 2>&1)"; rc=$?
[ "$rc" -eq 2 ] && printf '%s' "$vo" | grep -q 'requires a value'; check "retract: missing value is a usage error" $?
uo="$("$SEND" --retract no-such-broadcast.md --from retractor </dev/null 2>&1)"; rc=$?
[ "$rc" -eq 2 ] && printf '%s' "$uo" | grep -q 'not found'; check "retract of an unknown broadcast exits 2" $?
bad_rc=0
for bad in . .. sub/dir; do
bo="$("$SEND" --retract "$bad" --from retractor </dev/null 2>&1)"; brc=$?
{ [ "$brc" -eq 2 ] && printf '%s' "$bo" | grep -q 'invalid --retract'; } || bad_rc=1
done
[ "$bad_rc" -eq 0 ]; check "retract rejects . / .. / path names as invalid" $?
comb_rc=0
for combo in --broadcast "--to:x" "--reply-to:y"; do
cflag="${combo%%:*}"; cval="${combo#*:}"
if [ "$cval" = "$combo" ]; then
co="$("$SEND" --retract "$rbase" "$cflag" --from retractor </dev/null 2>&1)"; crc=$?
else
co="$("$SEND" --retract "$rbase" "$cflag" "$cval" --from retractor </dev/null 2>&1)"; crc=$?
fi
{ [ "$crc" -eq 2 ] && printf '%s' "$co" | grep -q 'cannot be combined'; } || comb_rc=1
done
[ "$comb_rc" -eq 0 ]; check "retract cannot be combined with --to/--broadcast/--reply-to" $?
ro="$("$SEND" --retract "$rbase" --from retractor </dev/null 2>&1)"; rc=$?
[ "$rc" -eq 0 ]; check "retract by the sender exits 0" $?
[ ! -e "$CLAUDE_COORD_DIR/_broadcast/inbox/$rbase" ]; check "retracted broadcast leaves the broadcast inbox" $?
[ -e "$CLAUDE_COORD_DIR/_broadcast/archive/$rbase" ]; check "retracted broadcast is archived, never deleted" $?
fout="$("$INBOX" --repo fresh-reader)"
[ "$(printf '%s' "$fout" | grep -c 'RETRACT-ME-BODY')" -eq 0 ]; check "retracted broadcast is never delivered to a new repo" $?
printf '%s' "$fout" | grep -q 'KEEP-BC-BODY'; check "unretracted broadcasts still reach that repo" $?
io="$("$SEND" --retract "$rbase" --from retractor </dev/null 2>&1)"; rc=$?
[ "$rc" -eq 0 ] && printf '%s' "$io" | grep -q 'already retracted'; check "re-retracting an already retracted broadcast is a no-op (exit 0)" $?
echo "----"
echo "PASS=$PASS FAIL=$FAIL"
[ "$FAIL" -eq 0 ]

View file

@ -6,9 +6,13 @@
# coord-send.sh --to <repo> --subject "<subject>" [--from <repo>] [--message "<text>"]
# coord-send.sh --broadcast --subject "<subject>" [--from <repo>] [--message "<text>"]
# coord-send.sh --reply-to <file> [--subject "Re: ..."] [--from <repo>] [--message "<text>"]
# coord-send.sh --retract <file> [--from <repo>]
# Body comes from --message, or from stdin (heredoc) when --message is omitted.
# --reply-to <basename> replies to a message in THIS repo's inbox/archive: it
# routes to the original sender and marks the original handled (coord-done).
# --retract <basename> retires one of YOUR OWN broadcasts: it is archived out of
# the broadcast queue so no future repo receives it. This is un-send, not
# recall - repos that already received it are unaffected.
# --from overrides the sender/self identity (default: basename of git toplevel/cwd).
#
# Exit: 0 delivered, 2 usage/IO error. ASCII only, bash 3.2 safe.
@ -18,6 +22,7 @@ export LC_ALL=C
COORD="${CLAUDE_COORD_DIR:-$HOME/.claude/coord}"
TO=""; BROADCAST=0; SUBJECT=""; FROM=""; MESSAGE=""; HAVE_MESSAGE=0; REPLYTO=""; REPLY_ORIG=""
RETRACT=""
# bash 3.2: `shift 2` past the end of $# is a no-op, so a trailing value-flag
# without its value would loop forever. Every two-arg flag must check first.
@ -30,6 +35,7 @@ while [ $# -gt 0 ]; do
--to) require_value --to $#; TO="$2"; shift 2 ;;
--broadcast) BROADCAST=1; shift ;;
--reply-to) require_value --reply-to $#; REPLYTO="$2"; shift 2 ;;
--retract) require_value --retract $#; RETRACT="$2"; shift 2 ;;
--subject) require_value --subject $#; SUBJECT="$2"; shift 2 ;;
--from) require_value --from $#; FROM="$2"; shift 2 ;;
--message) require_value --message $#; MESSAGE="$2"; HAVE_MESSAGE=1; shift 2 ;;
@ -52,6 +58,46 @@ fi
sanitize_field() { printf '%s' "$1" | tr '\r\n' ' ' | tr -d '\000-\037'; }
FROM="$(sanitize_field "$FROM")"
# --- Retract mode: retire one of our own broadcasts ---
# A broadcast has no per-repo owner that can close it: coord-done is directed-only
# and never touches _broadcast/. Without this branch a stale announcement stays in
# the queue and is delivered to every FUTURE repo forever, so the backlog can only
# grow. Runs before every send-side validation and before the stdin body read: a
# retract carries no subject and no body.
# The sender check is an accident guard, not a security boundary - --from
# redefines identity here exactly as it does everywhere else in this script. It
# exists so a wrong filename cannot silently retire another repo's announcement.
if [ -n "$RETRACT" ]; then
if [ "$BROADCAST" -eq 1 ] || [ -n "$TO" ] || [ -n "$REPLYTO" ]; then
echo "coord-send: --retract cannot be combined with --to/--broadcast/--reply-to" >&2; exit 2
fi
case "$RETRACT" in */*|.|..|"") echo "coord-send: invalid --retract name: $RETRACT" >&2; exit 2 ;; esac
BC_INBOX="$COORD/_broadcast/inbox"
BC_ARCHIVE="$COORD/_broadcast/archive"
if [ ! -e "$BC_INBOX/$RETRACT" ]; then
# Idempotent like coord-done: retracting twice is a no-op, not an error.
if [ -e "$BC_ARCHIVE/$RETRACT" ]; then
echo "coord-send: broadcast already retracted ($RETRACT)"; exit 0
fi
echo "coord-send: --retract broadcast not found: $RETRACT" >&2; exit 2
fi
ORIG_FROM="$(grep -m1 '^from:' "$BC_INBOX/$RETRACT" 2>/dev/null | sed 's/^from:[[:space:]]*//')"
if [ "$ORIG_FROM" != "$FROM" ]; then
echo "coord-send: refusing to retract a broadcast sent by ${ORIG_FROM:-unknown} (you are $FROM); pass --from ${ORIG_FROM:-<sender>} if that is really you" >&2
exit 2
fi
# Archived, never deleted (coord-done's rule), and the move stays inside
# _broadcast/ so it is a same-filesystem rename: no half-retracted state.
mkdir -p "$BC_ARCHIVE" 2>/dev/null || { echo "coord-send: cannot create $BC_ARCHIVE" >&2; exit 2; }
if ! mv "$BC_INBOX/$RETRACT" "$BC_ARCHIVE/$RETRACT" 2>/dev/null; then
echo "coord-send: retract failed for $RETRACT" >&2; exit 2
fi
# _broadcast/seen/* is deliberately left alone: those entries are delivery
# history, and one naming an archived file is inert.
echo "coord-send: retracted broadcast ($RETRACT); repos that already received it are unaffected"
exit 0
fi
# --- Reply mode: resolve target + default subject from the original message ---
if [ -n "$REPLYTO" ]; then
if [ "$BROADCAST" -eq 1 ] || [ -n "$TO" ]; then