Make remote and log resource ownership explicit

src/common/replicatorResources/shared.ts

@@ -1,3 +1,4 @@
+import { createOwnedResource } from "octagonal-wheels/resource";
 import type { RemoteDBSettings } from "@vrtmrz/livesync-commonlib/compat/common/types";
 
 /**
@@ -13,13 +14,8 @@ export interface ResourceReplicator {
 
 /** Create one idempotent asynchronous disposer for a private Replicator. */
 export function createReplicatorDisposer(replicator: ResourceReplicator): () => Promise<void> {
-    let disposal: Promise<void> | undefined;
-    return () => {
-        if (disposal === undefined) {
-            disposal = Promise.resolve().then(() => replicator.closeReplication());
-        }
-        return disposal;
-    };
+    const resource = createOwnedResource(replicator, (owned) => Promise.resolve().then(() => owned.closeReplication()));
+    return () => Promise.resolve(resource.dispose());
 }
 
 /** Fence a finite resource from later edits to its source settings object. */

src/common/replicatorResources/shared.unit.spec.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it, vi } from "vitest";
+import { createReplicatorDisposer } from "./shared";
+
+describe("Replicator disposal", () => {
+    it("defers closing, preserves the receiver, and retains one completion promise", async () => {
+        let finish!: () => void;
+        const closed = new Promise<void>((resolve) => {
+            finish = resolve;
+        });
+        const replicator = {
+            closeReplication: vi.fn(function (this: unknown) {
+                expect(this).toBe(replicator);
+                return closed;
+            }),
+        };
+        const dispose = createReplicatorDisposer(replicator);
+        const pending = dispose();
+        expect(replicator.closeReplication).not.toHaveBeenCalled();
+        expect(dispose()).toBe(pending);
+        await Promise.resolve();
+        expect(replicator.closeReplication).toHaveBeenCalledOnce();
+        finish();
+        await pending;
+        expect(dispose()).toBe(pending);
+        expect(replicator.closeReplication).toHaveBeenCalledOnce();
+    });
+
+    it("retains synchronous closing failures as one rejected promise", async () => {
+        const error = new Error("close");
+        const replicator = {
+            closeReplication: vi.fn(() => {
+                throw error;
+            }),
+        };
+        const dispose = createReplicatorDisposer(replicator);
+        const pending = dispose();
+        await expect(pending).rejects.toBe(error);
+        expect(dispose()).toBe(pending);
+        await expect(dispose()).rejects.toBe(error);
+        expect(replicator.closeReplication).toHaveBeenCalledOnce();
+    });
+});