fix: remove deprecated API, work around Deno bug

etag.ts

@@ -21,12 +21,11 @@ export {
   ifNoneMatch,
 } from "./deps.ts";
 
-function fstat(file: Deno.FsFile): Promise<Deno.FileInfo | undefined> {
-  if ("fstat" in Deno) {
-    // deno-lint-ignore no-explicit-any
-    return (Deno as any).fstat(file.rid);
-  }
-  return Promise.resolve(undefined);
+// This is to work around issue introduced in Deno 1.40
+// See: https://github.com/denoland/deno/issues/22115
+function isFsFile(value: unknown): value is Deno.FsFile {
+  return !!(value && typeof value === "object" && "stat" in value &&
+    typeof value.stat === "function");
 }
 
 /** For a given Context, try to determine the response body entity that an ETag
@@ -36,8 +35,8 @@ export function getEntity<S extends State = Record<string, any>>(
   context: Context<S>,
 ): Promise<string | Uint8Array | Deno.FileInfo | undefined> {
   const { body } = context.response;
-  if (body instanceof Deno.FsFile) {
-    return fstat(body);
+  if (isFsFile(body)) {
+    return body.stat();
   }
   if (body instanceof Uint8Array) {
     return Promise.resolve(body);

etag_test.ts

@@ -88,20 +88,8 @@ test({
 
     const mw = factory();
     await mw(context, next);
-    // Deno.fstat is currently an unstable API in Deno, but the code is written
-    // to fail gracefully, so we sniff if the API is unavailable and change
-    // the assertions accordingly.
-    if ("fstat" in Deno) {
-      const actual = context.response.headers.get("etag");
-      // mtime will vary from system to system which makes up part of the hash
-      // we we only look at the part that is consistent.
-      assert(actual && actual.startsWith(`W/"4a3b7-`));
-    } else {
-      assertEquals(
-        context.response.headers.get("etag"),
-        null,
-      );
-    }
+    const actual = context.response.headers.get("etag");
+    assert(actual && actual.startsWith(`W/"4a3b7-`));
 
     file!.close();
   },

response.ts

@@ -106,7 +106,7 @@ export class Response {
   #headers = new Headers();
   #jsonBodyReplacer?: (key: string, value: unknown) => unknown;
   #request: Request;
-  #resources: number[] = [];
+  #resources: { close(): void }[] = [];
   #status?: Status;
   #type?: string;
   #writable = true;
@@ -223,8 +223,8 @@ export class Response {
 
   /** Add a resource to the list of resources that will be closed when the
    * request is destroyed. */
-  addResource(rid: number): void {
-    this.#resources.push(rid);
+  addResource(resource: { close(): void }): void {
+    this.#resources.push(resource);
   }
 
   /** Release any resources that are being tracked by the response.
@@ -236,9 +236,9 @@ export class Response {
     this.#body = undefined;
     this.#domResponse = undefined;
     if (closeResources) {
-      for (const rid of this.#resources) {
+      for (const resource of this.#resources) {
         try {
-          Deno.close(rid);
+          resource.close();
         } catch {
           // we don't care about errors here
         }

send.ts

@@ -130,7 +130,7 @@ async function getEntity(
     file.close();
     body = entity = buffer;
   } else {
-    response.addResource(file.rid);
+    response.addResource(file);
     body = file;
     entity = {
       mtime: new Date(mtime!),