Tweak reentry guard

index.js

@@ -26,7 +26,7 @@ class Timer {
       this._expiry = now + this._list.ms
       this._list.push(this)
     } else {
-      if (this._refed === true) this.unref()
+      if (this._refed === true) decRef()
       this._list = null
     }
     // apply at the bottom to avoid re-entries...
@@ -36,7 +36,7 @@ class Timer {
   _clear () {
     if (this._list === null) return
     this._list.clear(this)
-    if (this._refed === true) this.unref()
+    if (this._refed === true) decRef()
     this._list = null
 
     maybeUpdateTimer()
@@ -57,14 +57,14 @@ class Timer {
   }
 
   unref () {
-    if (this._refed === false) return this
+    if (this._refed === false || this._list === null) return this
     this._refed = false
     decRef()
     return this
   }
 
   ref () {
-    if (this._refed === true) return this
+    if (this._refed === true || this._list === null) return this
     this._refed = true
     incRef()
     return this

test/all.js

@@ -1,3 +1,4 @@
 require('./immediate')
 require('./interval')
 require('./timeout')
+require('./ref') // has to be last one

test/unref.js → test/ref.js

@@ -13,3 +13,17 @@ test('unref and a timer stays alive', async function (t) {
     }, 50)
   }
 })
+
+// must be last test!
+test('ref in callbacks are noops', async function (t) {
+  t.plan(1)
+
+  const timer = timers.setTimeout(run, 10)
+
+  function run () {
+    timer.ref()
+    const other = timers.setTimeout(() => t.fail('should not run'), 10_000)
+    other.unref()
+    t.pass('timer triggered')
+  }
+})