improve debug logs

lib/index.js

@@ -32,6 +32,18 @@ function initGC(peer, config) {
   let stopMonitoringLogSize = /** @type {CallableFunction | null} */ (null)
   let hasCleanupScheduled = false
 
+  /**
+   * @param {Error} err
+   */
+  function flattenCauseChain(err) {
+    let str = ''
+    while (err?.message ?? err) {
+      str += (err.message ?? err) + ': '
+      err = /**@type {Error}*/ (err.cause)
+    }
+    return str
+  }
+
   /**
    * Deletes messages that don't correspond to any goal.
    * @private
@@ -40,12 +52,15 @@ function initGC(peer, config) {
   function cleanup(cb) {
     debug('Cleanup started')
     const startTime = Date.now()
-
     const done = multicb({ pluck: 1 })
-    function makeRecCB(/**@type {string}*/ errorMessage) {
+
+    /**
+     * @param {string} explanation
+     */
+    function makeRecCB(explanation) {
       const cb = done()
       return (/**@type {Error=}*/ err) => {
-        if (err) debug('%s: %s', errorMessage, err.message ?? err)
+        if (err) debug('%s: %s', explanation, flattenCauseChain(err))
         cb()
       }
     }
@@ -58,12 +73,14 @@ function initGC(peer, config) {
       if (purpose === 'goal') continue // don't cleanup
       if (purpose === 'none') {
         const recCB = makeRecCB('Failed to delete msg when cleaning up')
+        debug('Deleting msg %s with purpose=none', msgID)
         peer.db.del(msgID, recCB)
         waiting = true
       } else if (purpose === 'ghost') {
         const { tangleID, span } = details
         const recCB = makeRecCB('Failed to delete ghost msg when cleaning up')
         // TODO: Could one msg be a ghostable in MANY tangles? Or just one?
+        debug('Deleting and ghosting msg %s with purpose=ghost', msgID)
         peer.db.ghosts.add({ tangleID, msgID, span }, (err) => {
           if (err) return recCB(err)
           peer.db.del(msgID, recCB)
@@ -71,6 +88,7 @@ function initGC(peer, config) {
         waiting = true
       } else if (purpose === 'trail') {
         const recCB = makeRecCB('Failed to erase trail msg when cleaning up')
+        debug('Erasing msg %s with purpose=trail', msgID)
         peer.db.erase(msgID, recCB)
         waiting = true
       } else {