Continuous Learning V2

#!/usr/bin/env bash
# Continuous Learning v2 - Observer background loop
#
# Fix for #521: Added re-entrancy guard, cooldown throttle, and
# tail-based sampling to prevent memory explosion from runaway
# parallel Claude analysis processes.

set +e
unset CLAUDECODE

SLEEP_PID=""
USR1_FIRED=0
PENDING_ANALYSIS=0
ANALYZING=0
LAST_ANALYSIS_EPOCH=0
# Minimum seconds between analyses (prevents rapid re-triggering)
ANALYSIS_COOLDOWN="${ECC_OBSERVER_ANALYSIS_COOLDOWN:-60}"
IDLE_TIMEOUT_SECONDS="${ECC_OBSERVER_IDLE_TIMEOUT_SECONDS:-1800}"
SESSION_LEASE_DIR="${PROJECT_DIR}/.observer-sessions"
ACTIVITY_FILE="${PROJECT_DIR}/.observer-last-activity"

cleanup() {
  [ -n "$SLEEP_PID" ] && kill "$SLEEP_PID" 2>/dev/null
  if [ -f "$PID_FILE" ] && [ "$(cat "$PID_FILE" 2>/dev/null)" = "$$" ]; then
    rm -f "$PID_FILE"
  fi
  exit 0
}
trap cleanup TERM INT

file_mtime_epoch() {
  local file="$1"
  if [ ! -f "$file" ]; then
    printf '0\n'
    return
  fi

  if stat -c %Y "$file" >/dev/null 2>&1; then
    stat -c %Y "$file" 2>/dev/null || printf '0\n'
    return
  fi

  if stat -f %m "$file" >/dev/null 2>&1; then
    stat -f %m "$file" 2>/dev/null || printf '0\n'
    return
  fi

  printf '0\n'
}

has_active_session_leases() {
  if [ ! -d "$SESSION_LEASE_DIR" ]; then
    return 1
  fi

  find "$SESSION_LEASE_DIR" -type f -name '*.json' -print -quit 2>/dev/null | grep -q .
}

latest_activity_epoch() {
  local observations_epoch activity_epoch
  observations_epoch="$(file_mtime_epoch "$OBSERVATIONS_FILE")"
  activity_epoch="$(file_mtime_epoch "$ACTIVITY_FILE")"

  if [ "$activity_epoch" -gt "$observations_epoch" ] 2>/dev/null; then
    printf '%s\n' "$activity_epoch"
  else
    printf '%s\n' "$observations_epoch"
  fi
}

exit_if_idle_without_sessions() {
  if has_active_session_leases; then
    return
  fi

  local last_activity now_epoch idle_for
  last_activity="$(latest_activity_epoch)"
  now_epoch="$(date +%s)"
  idle_for=$(( now_epoch - last_activity ))

  if [ "$last_activity" -eq 0 ] || [ "$idle_for" -ge "$IDLE_TIMEOUT_SECONDS" ]; then
    echo "[$(date)] Observer idle without active session leases for ${idle_for}s; exiting" >> "$LOG_FILE"
    cleanup
  fi
}

wait_for_claude_analysis() {
  local child_pid="$1"
  local wait_status=0

  while true; do
    wait "$child_pid"
    wait_status=$?

    if [ "$wait_status" -eq 0 ]; then
      return 0
    fi

    # SIGUSR1 can interrupt wait while the Claude child is still running.
    # Re-wait in that case so a signal is not logged as a false child failure.
    if kill -0 "$child_pid" 2>/dev/null; then
      continue
    fi

    return "$wait_status"
  done
}

analyze_observations() {
  if [ ! -f "$OBSERVATIONS_FILE" ]; then
    return
  fi

  obs_count=$(wc -l < "$OBSERVATIONS_FILE" 2>/dev/null || echo 0)
  if [ "$obs_count" -lt "$MIN_OBSERVATIONS" ]; then
    return
  fi

  echo "[$(date)] Analyzing $obs_count observations for project ${PROJECT_NAME}..." >> "$LOG_FILE"

  if [ "${CLV2_IS_WINDOWS:-false}" = "true" ] && [ "${ECC_OBSERVER_ALLOW_WINDOWS:-false}" != "true" ]; then
    echo "[$(date)] Skipping claude analysis on Windows due to known non-interactive hang issue (#295). Set ECC_OBSERVER_ALLOW_WINDOWS=true to override." >> "$LOG_FILE"
    return
  fi

  if ! command -v claude >/dev/null 2>&1; then
    echo "[$(date)] claude CLI not found, skipping analysis" >> "$LOG_FILE"
    return
  fi

  # session-guardian: gate observer cycle (active hours, cooldown, idle detection)
  if ! bash "$(dirname "$0")/session-guardian.sh"; then
    echo "[$(date)] Observer cycle skipped by session-guardian" >> "$LOG_FILE"
    return
  fi

  # Sample recent observations instead of loading the entire file (#521).
  # This prevents multi-MB payloads from being passed to the LLM.
  MAX_ANALYSIS_LINES="${ECC_OBSERVER_MAX_ANALYSIS_LINES:-500}"
  observer_tmp_dir="${PROJECT_DIR}/.observer-tmp"
  mkdir -p "$observer_tmp_dir"
  analysis_file="$(mktemp "${observer_tmp_dir}/ecc-observer-analysis.XXXXXX.jsonl")"
  tail -n