fix: ensure onConnect is always called

lib/core/request.js

@@ -25,6 +25,7 @@ const { headerNameLowerCasedRecord } = require('./constants')
 const invalidPathRegex = /[^\u0021-\u00ff]/
 
 const kHandler = Symbol('handler')
+const noop = () => {}
 
 class Request {
   constructor (origin, {
@@ -223,7 +224,7 @@ class Request {
       abort(this.error)
     } else {
       this.abort = abort
-      return this[kHandler].onConnect(abort)
+      this[kHandler].onConnect(abort)
     }
   }
 
@@ -295,6 +296,14 @@ class Request {
     }
     this.aborted = true
 
+    if (!this.abort) {
+      // Make sure to always call onConnect even on errors to avoid
+      // a common user mistake of assuming that onConnect is always
+      // called before any other hook.
+      this.abort = noop
+      this[kHandler].onConnect(noop)
+    }
+
     return this[kHandler].onError(error)
   }