fix(cli/js/web/worker): Disable relative module specifiers (#5266)

7 files changed, 80 insertions, 55 deletions

diff --git a/cli/js/lib.deno.shared_globals.d.ts b/cli/js/lib.deno.shared_globals.d.ts
index a93ff1166..58d25cea4 100644
--- a/cli/js/lib.deno.shared_globals.d.ts
+++ b/cli/js/lib.deno.shared_globals.d.ts
@@ -1300,7 +1300,10 @@ declare class Worker extends EventTarget {
        *
        * ```ts
        * // mod.ts
-       * const worker = new Worker("./deno_worker.ts", { type: "module", deno: true });
+       * const worker = new Worker(
+       *   new URL("deno_worker.ts", import.meta.url).href,
+       *   { type: "module", deno: true }
+       * );
        * worker.postMessage({ cmd: "readFile", fileName: "./log.txt" });
        *
        * // deno_worker.ts
diff --git a/cli/ops/worker_host.rs b/cli/ops/worker_host.rs
index 0ed700431..950797352 100644
--- a/cli/ops/worker_host.rs
+++ b/cli/ops/worker_host.rs
@@ -193,13 +193,11 @@ fn op_create_worker(
   let mut state = state.borrow_mut();
   let global_state = state.global_state.clone();
   let permissions = state.permissions.clone();
-  let referrer = state.main_module.to_string();
   let worker_id = state.next_worker_id;
   state.next_worker_id += 1;
   drop(state);
 
-  let module_specifier =
-    ModuleSpecifier::resolve_import(&specifier, &referrer)?;
+  let module_specifier = ModuleSpecifier::resolve_url(&specifier)?;
   let worker_name = args_name.unwrap_or_else(|| "".to_string());
 
   let (join_handle, worker_handle) = run_worker_thread(
diff --git a/cli/tests/subdir/nested_worker.js b/cli/tests/subdir/nested_worker.js
index f5ac23a19..d3801b8c5 100644
--- a/cli/tests/subdir/nested_worker.js
+++ b/cli/tests/subdir/nested_worker.js
@@ -1,8 +1,8 @@
 // Specifier should be resolved relative to current file
-const jsWorker = new Worker("./sibling_worker.js", {
-  type: "module",
-  name: "sibling",
-});
+const jsWorker = new Worker(
+  new URL("sibling_worker.js", import.meta.url).href,
+  { type: "module", name: "sibling" }
+);
 
 jsWorker.onerror = (_e) => {
   postMessage({ type: "error" });
diff --git a/cli/tests/workers_round_robin_bench.ts b/cli/tests/workers_round_robin_bench.ts
index c7a683459..d7224b41d 100644
--- a/cli/tests/workers_round_robin_bench.ts
+++ b/cli/tests/workers_round_robin_bench.ts
@@ -37,7 +37,10 @@ function handleAsyncMsgFromWorker(
 async function main(): Promise<void> {
   const workers: Array<[Map<number, Resolvable<string>>, Worker]> = [];
   for (let i = 1; i <= workerCount; ++i) {
-    const worker = new Worker("./subdir/bench_worker.ts", { type: "module" });
+    const worker = new Worker(
+      new URL("subdir/bench_worker.ts", import.meta.url).href,
+      { type: "module" }
+    );
     const promise = createResolvable<void>();
     worker.onmessage = (e): void => {
       if (e.data.cmdId === 0) promise.resolve();
diff --git a/cli/tests/workers_startup_bench.ts b/cli/tests/workers_startup_bench.ts
index 60c15a4b1..a25dc8ff7 100644
--- a/cli/tests/workers_startup_bench.ts
+++ b/cli/tests/workers_startup_bench.ts
@@ -4,7 +4,10 @@ const workerCount = 50;
 async function bench(): Promise<void> {
   const workers: Worker[] = [];
   for (let i = 1; i <= workerCount; ++i) {
-    const worker = new Worker("./subdir/bench_worker.ts", { type: "module" });
+    const worker = new Worker(
+      new URL("subdir/bench_worker.ts", import.meta.url).href,
+      { type: "module" }
+    );
     const promise = new Promise((resolve): void => {
       worker.onmessage = (e): void => {
         if (e.data.cmdId === 0) resolve();
diff --git a/cli/tests/workers_test.ts b/cli/tests/workers_test.ts
index df2cdf2aa..feab0f9c2 100644
--- a/cli/tests/workers_test.ts
+++ b/cli/tests/workers_test.ts
@@ -32,13 +32,14 @@ Deno.test({
   fn: async function (): Promise<void> {
     const promise = createResolvable();
 
-    const jsWorker = new Worker("../tests/subdir/test_worker.js", {
-      type: "module",
-    });
-    const tsWorker = new Worker("../tests/subdir/test_worker.ts", {
-      type: "module",
-      name: "tsWorker",
-    });
+    const jsWorker = new Worker(
+      new URL("subdir/test_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
+    const tsWorker = new Worker(
+      new URL("subdir/test_worker.ts", import.meta.url).href,
+      { type: "module", name: "tsWorker" }
+    );
 
     tsWorker.onmessage = (e): void => {
       assertEquals(e.data, "Hello World");
@@ -67,10 +68,10 @@ Deno.test({
   fn: async function (): Promise<void> {
     const promise = createResolvable();
 
-    const nestedWorker = new Worker("../tests/subdir/nested_worker.js", {
-      type: "module",
-      name: "nested",
-    });
+    const nestedWorker = new Worker(
+      new URL("subdir/nested_worker.js", import.meta.url).href,
+      { type: "module", name: "nested" }
+    );
 
     nestedWorker.onmessage = (e): void => {
       assert(e.data.type !== "error");
@@ -87,9 +88,10 @@ Deno.test({
   name: "worker throws when executing",
   fn: async function (): Promise<void> {
     const promise = createResolvable();
-    const throwingWorker = new Worker("../tests/subdir/throwing_worker.js", {
-      type: "module",
-    });
+    const throwingWorker = new Worker(
+      new URL("subdir/throwing_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     throwingWorker.onerror = (e: any): void => {
@@ -108,9 +110,10 @@ Deno.test({
   fn: async function (): Promise<void> {
     const promise = createResolvable();
 
-    const fetchingWorker = new Worker("../tests/subdir/fetching_worker.js", {
-      type: "module",
-    });
+    const fetchingWorker = new Worker(
+      new URL("subdir/fetching_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     fetchingWorker.onerror = (e: any): void => {
@@ -134,9 +137,10 @@ Deno.test({
   fn: async function (): Promise<void> {
     const promise = createResolvable();
 
-    const busyWorker = new Worker("../tests/subdir/busy_worker.js", {
-      type: "module",
-    });
+    const busyWorker = new Worker(
+      new URL("subdir/busy_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     let testResult = 0;
 
@@ -166,9 +170,10 @@ Deno.test({
     // https://github.com/denoland/deno/issues/4080
     const promise = createResolvable();
 
-    const racyWorker = new Worker("../tests/subdir/racy_worker.js", {
-      type: "module",
-    });
+    const racyWorker = new Worker(
+      new URL("subdir/racy_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     racyWorker.onmessage = (e): void => {
       assertEquals(e.data.buf.length, 999999);
@@ -193,9 +198,10 @@ Deno.test({
     const promise1 = createResolvable();
     const promise2 = createResolvable();
 
-    const worker = new Worker("../tests/subdir/event_worker.js", {
-      type: "module",
-    });
+    const worker = new Worker(
+      new URL("subdir/event_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     worker.onmessage = (_e: Event): void => {
       messageHandlersCalled++;
@@ -236,9 +242,10 @@ Deno.test({
   fn: async function (): Promise<void> {
     const promise1 = createResolvable();
 
-    const worker = new Worker("../tests/subdir/event_worker_scope.js", {
-      type: "module",
-    });
+    const worker = new Worker(
+      new URL("subdir/event_worker_scope.js", import.meta.url).href,
+      { type: "module" }
+    );
 
     worker.onmessage = (e: MessageEvent): void => {
       const { messageHandlersCalled, errorHandlersCalled } = e.data;
@@ -264,13 +271,14 @@ Deno.test({
     const promise = createResolvable();
     const promise2 = createResolvable();
 
-    const regularWorker = new Worker("../tests/subdir/non_deno_worker.js", {
-      type: "module",
-    });
-    const denoWorker = new Worker("../tests/subdir/deno_worker.ts", {
-      type: "module",
-      deno: true,
-    });
+    const regularWorker = new Worker(
+      new URL("subdir/non_deno_worker.js", import.meta.url).href,
+      { type: "module" }
+    );
+    const denoWorker = new Worker(
+      new URL("subdir/deno_worker.ts", import.meta.url).href,
+      { type: "module", deno: true }
+    );
 
     regularWorker.onmessage = (e): void => {
       assertEquals(e.data, "Hello World");
@@ -295,9 +303,10 @@ Deno.test({
   name: "worker with crypto in scope",
   fn: async function (): Promise<void> {
     const promise = createResolvable();
-    const w = new Worker("../tests/subdir/worker_crypto.js", {
-      type: "module",
-    });
+    const w = new Worker(
+      new URL("subdir/worker_crypto.js", import.meta.url).href,
+      { type: "module" }
+    );
     w.onmessage = (e): void => {
       assertEquals(e.data, true);
       promise.resolve();
diff --git a/docs/runtime/workers.md b/docs/runtime/workers.md
index 110255b8b..019df7201 100644
--- a/docs/runtime/workers.md
+++ b/docs/runtime/workers.md
@@ -7,15 +7,21 @@ Workers can be used to run code on multiple threads. Each instance of `Worker`
 is run on a separate thread, dedicated only to that worker.
 
 Currently Deno supports only `module` type workers; thus it's essential to pass
-`type: "module"` option when creating a new worker:
+the `type: "module"` option when creating a new worker.
+
+Relative module specifiers are
+[not supported](https://github.com/denoland/deno/issues/5216) at the moment. You
+can instead use the `URL` contructor and `import.meta.url` to easily create a
+specifier for some nearby script.
 
 ```ts
 // Good
-new Worker("./worker.js", { type: "module" });
+new Worker(new URL("worker.js", import.meta.url).href, { type: "module" });
 
 // Bad
-new Worker("./worker.js");
-new Worker("./worker.js", { type: "classic" });
+new Worker(new URL("worker.js", import.meta.url).href);
+new Worker(new URL("worker.js", import.meta.url).href, { type: "classic" });
+new Worker("./worker.js", { type: "module" });
 ```
 
 ### Permissions
@@ -28,7 +34,7 @@ For workers using local modules; `--allow-read` permission is required:
 **main.ts**
 
 ```ts
-new Worker("./worker.ts", { type: "module" });
+new Worker(new URL("worker.ts", import.meta.url).href, { type: "module" });
 ```
 
 **worker.ts**
@@ -81,7 +87,10 @@ To add the `Deno` namespace pass `deno: true` option when creating new worker:
 **main.js**
 
 ```ts
-const worker = new Worker("./worker.js", { type: "module", deno: true });
+const worker = new Worker(new URL("worker.js", import.meta.url).href, {
+  type: "module",
+  deno: true,
+});
 worker.postMessage({ filename: "./log.txt" });
 ```