feat(log): per-line cwd + source-aware emit label (#33)

* feat(log): per-line cwd + source-aware emit label

Two annoyances surfaced when dogfooding v0.2.0 across multiple
projects:

1. Lines in the global `~/.context-revive/hook.log` did not carry
   any project context. With revive wired in 5+ repos, the same
   `post-compact: forcing emit` message could be from any of them
   — un-debuggable.
2. The forcing-emit log line said `post-compact:` even when the
   trigger was `/clear`, because both paths shared one signal file
   and `cadence_gate` had no idea which command wrote it.

Fixes:

- `log()` now prepends `[<cwd>]` after the timestamp, with a
  tilde substitution for paths under $HOME. A subtle bash gotcha:
  `${VAR/old/\~}` leaks the backslash; bash does NOT tilde-expand
  inside parameter-substitution replacements, so the literal `~`
  is correct (and was wrong on my first attempt — caught in
  smoke before commit).

- `cmd_mark_compact` and `cmd_mark_clear` write `compact` / `clear`
  to the signal file (was: a unix timestamp, never read). The
  signal filename stays `revive-compact.signal` to keep the
  on-disk path stable across upgrades.

- `cadence_gate` reads the payload, sanitizes via
  `tr -cd '[:lower:]'`, and emits either `post-compact:` or
  `post-clear:` accordingly. Unknown / malformed content falls
  back to a neutral `post-context-loss:` label.

4 new tests cover: cwd field present in log, compact label,
clear label, malformed payload → neutral label without crashing.

* test(log): hold cwd-format regex in a variable for portability

The inline `[[ "$output" =~ \[[^]]+\]\ \[[^]]+\]\ post-compact ]]`
passed on macOS bats but failed on Ubuntu bats in CI — bash 3.2 vs
5.x differ on how literal `\[` inside the pattern is parsed. The
canonical workaround is to bind the pattern to a local variable
and reference it as `$re`. No content change to the assertion.

* fix(log): match $HOME on path boundary only (codex P2)

`${PWD/#$HOME/~}` did a string-prefix rewrite without a path
boundary check, so a checkout in `$HOME-something/...` (e.g.
HOME=/Users/alice and PWD=/Users/alice-work/project) would log
as `~-work/project` — wrong project name in a feature that
exists specifically to disambiguate projects.

Replace with a case statement that fires only on the exact
$HOME match or the `$HOME/` prefix; falls through to the
absolute path otherwise.

New test pins this: stages a sibling worktree at `$WORKDIR-other`
with HOME=$WORKDIR, runs mark-compact, and asserts the log line
does NOT contain the `~-other` splice artefact.

* test(log): clean up compact-source test setup (copilot)

Replaced the convoluted `printf > .claude/... 2>/dev/null
|| mkdir -p .claude && printf > .claude/...` with the same
two-line pattern the sibling clear-source and garbage-payload
tests already use. Bash redirect failures land on the original
stderr before `2>/dev/null` is applied, so the old form would
have leaked an error noise even when functionally correct.

Author: justi

bin/revive

@@ -53,7 +53,18 @@ cmd_version() { echo "revive $VERSION"; }
 
 log() {
   mkdir -p "$LOG_DIR" 2>/dev/null || return 0
-  printf '[%s] %s\n' "$(date '+%Y-%m-%dT%H:%M:%S')" "$*" \
+  # Tilde-substitute $HOME so multi-project logs stay scannable. Match
+  # only on a path boundary — `${PWD/#$HOME/~}` would happily rewrite
+  # `/Users/alice-work/project` to `~-work/project` when HOME is
+  # `/Users/alice` (codex P2). Use case to require either exact match
+  # or `$HOME/` prefix.
+  local cwd_short
+  case "$PWD" in
+    "$HOME")    cwd_short="~" ;;
+    "$HOME"/*)  cwd_short="~${PWD#"$HOME"}" ;;
+    *)          cwd_short="$PWD" ;;
+  esac
+  printf '[%s] [%s] %s\n' "$(date '+%Y-%m-%dT%H:%M:%S')" "$cwd_short" "$*" \
     >> "$LOG_FILE" 2>/dev/null || true
 }
 
@@ -411,8 +422,14 @@ cadence_gate() {
   # most of its context — that's exactly when re-injecting the brief gives
   # the highest ROI, so bypass cadence and emit immediately.
   if [[ -f "$COMPACT_SIGNAL" ]]; then
+    # The signal file payload identifies the trigger ("compact" / "clear").
+    # Sanitize to a-z only — defense-in-depth in case content was mangled.
+    # Empty or unknown content falls back to a neutral label.
+    local source
+    source=$(head -1 "$COMPACT_SIGNAL" 2>/dev/null | tr -cd '[:lower:]')
+    [[ "$source" == compact || "$source" == clear ]] || source="context-loss"
     rm -f "$COMPACT_SIGNAL" 2>/dev/null || true
-    log "post-compact: forcing emit (counter=$n)"
+    log "post-${source}: forcing emit (counter=$n)"
     emit=1
   elif (( n == 1 )); then emit=1
   elif (( n % REFRESH_EVERY == 0 )); then emit=1
@@ -446,14 +463,14 @@ cmd_show() {
 # path and must never break a Claude Code session.
 cmd_mark_compact() {
   mkdir -p "$(dirname "$COMPACT_SIGNAL")" 2>/dev/null || return 0
-  date +%s > "$COMPACT_SIGNAL" 2>/dev/null || return 0
+  printf 'compact\n' > "$COMPACT_SIGNAL" 2>/dev/null || return 0
   log "post-compact signal written: $COMPACT_SIGNAL"
   return 0
 }
 
 cmd_mark_clear() {
   mkdir -p "$(dirname "$COMPACT_SIGNAL")" 2>/dev/null || return 0
-  date +%s > "$COMPACT_SIGNAL" 2>/dev/null || return 0
+  printf 'clear\n' > "$COMPACT_SIGNAL" 2>/dev/null || return 0
   log "post-clear signal written: $COMPACT_SIGNAL"
   return 0
 }

tests/revive.bats

@@ -1570,3 +1570,64 @@ JSON
   [[ "$output" == *"PostCompact hook installed"* ]] || return 1
   [[ "$output" == *"SessionStart(clear) hook installed"* ]] || return 1
 }
+
+# --- log enrichments ---
+
+@test "log lines carry the cwd field for multi-project scanability" {
+  # mark-compact always logs (refresh on a fresh repo doesn't, since the
+  # counter-1 emit path doesn't go through log()). The mark-compact line
+  # must carry [<cwd>] so a global hook.log collected from many projects
+  # stays disambiguable.
+  mkdir -p .claude
+  "$REVIVE" mark-compact
+  run cat "$HOME/.context-revive/hook.log"
+  [[ "$output" == *"signal written"* ]] || return 1
+  # Format: [timestamp] [cwd] message — must have TWO bracketed fields
+  # before the message body. Regex held in a variable to avoid the bash
+  # =~ backslash-quoting differences between macOS bash 3.2 and CI's
+  # bash 5.x (literal \[ inside the inline pattern is unportable).
+  local re='\[[^]]+\] \[[^]]+\] post-compact'
+  [[ "$output" =~ $re ]] || return 1
+}
+
+@test "refresh log message reflects compact source" {
+  mkdir -p .claude
+  printf 'compact\n' > .claude/revive-compact.signal
+  "$REVIVE" refresh >/dev/null
+  run cat "$HOME/.context-revive/hook.log"
+  [[ "$output" == *"post-compact: forcing emit"* ]] || return 1
+}
+
+@test "refresh log message reflects clear source" {
+  mkdir -p .claude
+  printf 'clear\n' > .claude/revive-compact.signal
+  "$REVIVE" refresh >/dev/null
+  run cat "$HOME/.context-revive/hook.log"
+  [[ "$output" == *"post-clear: forcing emit"* ]] || return 1
+  [[ "$output" != *"post-compact: forcing emit"* ]] || return 1
+}
+
+@test "refresh handles a malformed signal payload with neutral label" {
+  mkdir -p .claude
+  # Garbage content — must NOT mislabel as compact/clear, must NOT crash.
+  printf '\x00\x01garbage\n' > .claude/revive-compact.signal
+  run "$REVIVE" refresh
+  [ "$status" -eq 0 ] || return 1
+  run cat "$HOME/.context-revive/hook.log"
+  [[ "$output" == *"post-context-loss: forcing emit"* ]] || return 1
+}
+
+@test "log cwd prefix-match respects path boundary (codex P2)" {
+  # When HOME is `/tmp/h` and PWD is `/tmp/h-other/project`, the lazy
+  # `${PWD/#$HOME/~}` would mis-emit `~-other/project` and the global
+  # log would attribute the message to the wrong project. The case-based
+  # rewrite must only fire on `$HOME` or `$HOME/...`.
+  mkdir -p "$WORKDIR-other/project/.claude"
+  cd "$WORKDIR-other/project"
+  HOME="$WORKDIR" "$REVIVE" mark-compact
+  run cat "$WORKDIR/.context-revive/hook.log"
+  [[ "$output" == *"signal written"* ]] || { rm -rf "$WORKDIR-other"; return 1; }
+  # The log line must NOT contain the spliced `~-other` artefact.
+  [[ "$output" != *"~-other"* ]] || { rm -rf "$WORKDIR-other"; return 1; }
+  rm -rf "$WORKDIR-other"
+}