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tmux-persist: never let an empty snapshot clobber a saved manifest
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emo's 5 web-terminal tmux sessions were OOM-killed (the server died, no
reboot), and the 5-minute save tick then overwrote his session manifest with
0 bytes — wiping the record that restore needs. Root cause: the save guard
only checked that the tmux socket *file* existed, but an OOM-killed server
leaves a stale /tmp/tmux-<uid>/default behind; list-panes then returns
nothing and that empty capture was installed over the good manifest. Because
the restore service only runs at boot, an OOM (not a reboot) skips restore
entirely, so the clobbered manifest was the only record left — and it was
already gone.

Fix: only overwrite <user>.tsv when the snapshot captured >=1 live session;
otherwise keep the last good manifest (now covers no-server AND
stale-socket/dead-server). Verified by reproducing the 0-byte clobber on the
old script and confirming the new one preserves the manifest, plus a live
save that still captures every active session.

emo's 5 sessions were recovered from their transcripts and are back; this
keeps the next OOM from destroying the manifest again.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Viktor Barzin 2026-06-10 20:38:59 +00:00
parent 9fff77cbea
commit ac6f19dd3b
1 changed files with 18 additions and 6 deletions
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24
scripts/tmux-persist.sh
View file

@ -12,8 +12,9 @@
# transcript fd (~/.claude/projects/<slug>/<uuid>.jsonl), so it is
# correct regardless of how the session was launched (fresh via
# start-claude.sh or an explicit --resume). Runs every 5 min via
# tmux-persist-save.timer. A user with no tmux server keeps their last
# manifest (so a post-reboot save can't wipe it before restore).
# tmux-persist-save.timer. A snapshot that captures no live sessions
# (no server, OR a stale socket left behind by an OOM-killed server)
# keeps the user's last manifest, so it can't be wiped before restore.
# restore — recreate manifest sessions that don't currently exist, resuming
# each saved conversation (claude --resume <uuid>). Per-session
# idempotent: existing names are left alone, so it is safe both at
@ -70,10 +71,10 @@ uuid_of_claude() {
save() {
install -d -m 0755 "$STATE_DIR"
local u uid sess pane_pid pane_cwd cpid uuid tmp
local u uid sess pane_pid pane_cwd cpid uuid tmp n
for u in $(users); do
uid="$(id -u "$u" 2>/dev/null)" || continue
[[ -S "/tmp/tmux-$uid/default" ]] || continue # no server -> keep last manifest
[[ -S "/tmp/tmux-$uid/default" ]] || continue # no socket at all -> keep last manifest
tmp="$(mktemp)"
while IFS=$'\t' read -r sess pane_pid pane_cwd; do
[[ -n "$sess" ]] || continue
@ -82,8 +83,19 @@ save() {
printf '%s\t%s\t%s\n' "$sess" "$pane_cwd" "$uuid" >> "$tmp"
done < <(tmux_as "$u" list-panes -a -F $'#{session_name}\t#{pane_pid}\t#{pane_current_path}' 2>/dev/null \
| sort -u -t$'\t' -k1,1)
install -m 0600 "$tmp" "$STATE_DIR/$u.tsv"; rm -f "$tmp"
log "saved $(wc -l < "$STATE_DIR/$u.tsv") session(s) for $u"
# Only overwrite the manifest when we captured >=1 live session. A socket
# file can outlive its server (an OOM-killed tmux server leaves
# /tmp/tmux-<uid>/default behind); list-panes then yields nothing, and
# installing that empty result would clobber a good manifest right before
# restore needs it. Empty capture -> keep the last good manifest.
n=$(wc -l < "$tmp")
if (( n > 0 )); then
install -m 0600 "$tmp" "$STATE_DIR/$u.tsv"
log "saved $n session(s) for $u"
else
log "no live sessions for $u (stale socket or dead server) — keeping last manifest"
fi
rm -f "$tmp"
done
}