fail Register when there is a conflicting registration with the same scope

Author: wanderview

docs/index.bs

@@ -123,7 +123,6 @@ spec: webappsec-referrer-policy; urlPrefix: https://w3c.github.io/webappsec-refe
 </pre>
 
 <!-- TODO: uncontrol old clients that no longer match in Activate -->
-<!-- TODO: look for conflicting scopes -->
 
 <section>
   <h2 id="motivations">Motivations</h2>
@@ -2616,6 +2615,10 @@ spec: webappsec-referrer-policy; urlPrefix: https://w3c.github.io/webappsec-refe
           1. If |newestWorker| is not null, |job|'s [=job/scope url=] [=url/equals=] |newestWorker|'s [=service worker/scope url=], |job|'s [=job/script url=] [=url/equals=] |newestWorker|'s [=service worker/script url=], |job|'s [=job/worker type=] equals |newestWorker|'s [=service worker/type=], and |job|'s [=job/update via cache mode=]'s value equals |registration|'s [=service worker registration/update via cache mode=], then:
               1. Invoke [=Resolve Job Promise=] with |job| and |registration|.
               1. Invoke <a>Finish Job</a> with |job| and abort these steps.
+          1. Let |scopeRegistration| be the result of running the <a>Get Registration By Scope</a> algorithm passing |job|'s [=job/scope url=] as the argument.
+          1. If |scopeRegistration| is not null, |scopeRegistration| is not |registration|, and |scopeRegistration|'s <a>active worker</a>'s [=service worker/scope url=] [=url/equals=] |job|'s [=job/scope url=], then:
+              1. Invoke [=Reject Job Promise=] with |job| and "{{InvalidStateError}}" {{DOMException}}.
+              1. Invoke <a>Finish Job</a> with |job| and abort these steps.
       1. Else:
           1. Invoke <a>Set Registration</a> algorithm with |job|'s [=job/origin=], |job|'s [=job/id=], and |job|'s [=job/update via cache mode=].
       1. Invoke <a>Update</a> algorithm passing |job| as the argument.
@@ -3404,12 +3407,30 @@ spec: webappsec-referrer-policy; urlPrefix: https://w3c.github.io/webappsec-refe
       :: |origin|, a [=environment settings object/origin=]
       :: |id|, a [=service worker registration/id=]
       : Output
-      :: A [=/service worker registration=]
+      :: A [=/service worker registration=] or null.
 
       1. Run the following steps atomically.
       1. [=map/Get=] (|origin|,|id|) from [=registration map=] and return the result.
   </section>
 
+  <section algorithm>
+    <h3 id="get-registration-by-scope-algorithm"><dfn>Get Registration By Scope</dfn></h3>
+
+      : Input
+      :: |scope|, a [=URL=]
+      : Output
+      :: A [=/service worker registration=] or null.
+
+      1. Run the following steps atomically.
+      1. [=map/For each=] |key| → |value| of <a>registration map</a>:
+          1. If |value|'s <a>active worker</a>'s [=service worker/scope url=] [=url/equals=] |scope|, then return |value|.
+          1. If |value|'s <a>waiting worker</a>'s [=service worker/scope url=] [=url/equals=] |scope|, then return |value|.
+          1. If |value|'s <a>installing worker</a>'s [=service worker/scope url=] [=url/equals=] |scope|, then return |value|.
+      1. Return null.
+
+      Note: Only one registration should be associated with a given scope at a time since we fail <a>Register</a> when there is a conflicting registration with the same scope.
+  </section>
+
   <section algorithm>
     <h3 id="get-newest-worker-algorithm"><dfn>Get Newest Worker</dfn></h3>