use a class for the fake signal instead

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend-common/src/context/RootContext.ts

@@ -18,34 +18,32 @@ import { Context } from './types';
 
 /**
  * Since the root context can never abort, and since nobody is ever meant to
- * dispatch events through it, we can use a static fake instance for
- * efficiency.
+ * dispatch events through it, we can use a static fake instance for efficiency.
+ *
+ * The reason that this was initially made for the root context is that due to
+ * the way that we always chain contexts off of it, sometimes a huge number of
+ * listeners want to add themselves to something that effectively never can be
+ * aborted in the first place. This triggered warnings that the max listeners
+ * limit was exceeded.
  */
-const fakeAbortController = new AbortController();
-const fakeAbortSignal: AbortSignal = Object.freeze(
-  Object.assign(
-    {
-      aborted: false,
-      reason: undefined,
-      throwIfAborted() {},
-      onabort() {},
-      addEventListener() {},
-      removeEventListener() {},
-      dispatchEvent() {
-        return true;
-      },
-    },
-    fakeAbortController.signal,
-  ),
-);
+class FakeAbortSignal implements AbortSignal {
+  readonly aborted = false;
+  readonly reason = undefined;
+  onabort() {}
+  throwIfAborted() {}
+  addEventListener() {}
+  removeEventListener() {}
+  dispatchEvent() {
+    return true;
+  }
+}
 
 /**
  * An empty root context.
  */
 export class RootContext implements Context {
-  readonly abortSignal = fakeAbortSignal;
+  readonly abortSignal = new FakeAbortSignal();
   readonly deadline = undefined;
-
   value<T = unknown>(_key: string): T | undefined {
     return undefined;
   }

packages/backend-tasks/src/tasks/util.test.ts

@@ -20,7 +20,7 @@ import { delegateAbortController, nowPlus, sleep, validateId } from './util';
 
 class KnexBuilder {
   public build(client: string): Knex {
-    return knexFactory({ client });
+    return knexFactory({ client, useNullAsDefault: true });
   }
 }