fix(node): stat/statSync returns instance of fs.Stats (#22294)

Fixes https://github.com/denoland/deno/issues/22291

---------

Signed-off-by: Divy Srivastava <dj.srivastava23@gmail.com>

4 files changed, 111 insertions, 12 deletions

diff --git a/ext/node/polyfills/_fs/_fs_stat.ts b/ext/node/polyfills/_fs/_fs_stat.ts
index 119faecee..de9b69ba3 100644
--- a/ext/node/polyfills/_fs/_fs_stat.ts
+++ b/ext/node/polyfills/_fs/_fs_stat.ts
@@ -5,13 +5,16 @@
 
 import { denoErrorToNodeError } from "ext:deno_node/internal/errors.ts";
 import { promisify } from "ext:deno_node/internal/util.mjs";
+import { primordials } from "ext:core/mod.js";
+
+const { ObjectCreate, ObjectAssign } = primordials;
 
 export type statOptions = {
   bigint: boolean;
   throwIfNoEntry?: boolean;
 };
 
-export type Stats = {
+interface IStats {
   /** ID of the device containing the file.
    *
    * _Linux/Mac OS only._ */
@@ -80,9 +83,84 @@ export type Stats = {
   isFile: () => boolean;
   isSocket: () => boolean;
   isSymbolicLink: () => boolean;
-};
+}
+
+class StatsBase {
+  constructor(
+    dev,
+    mode,
+    nlink,
+    uid,
+    gid,
+    rdev,
+    blksize,
+    ino,
+    size,
+    blocks,
+  ) {
+    this.dev = dev;
+    this.mode = mode;
+    this.nlink = nlink;
+    this.uid = uid;
+    this.gid = gid;
+    this.rdev = rdev;
+    this.blksize = blksize;
+    this.ino = ino;
+    this.size = size;
+    this.blocks = blocks;
+  }
+}
+
+// The Date constructor performs Math.floor() to the timestamp.
+// https://www.ecma-international.org/ecma-262/#sec-timeclip
+// Since there may be a precision loss when the timestamp is
+// converted to a floating point number, we manually round
+// the timestamp here before passing it to Date().
+function dateFromMs(ms) {
+  return new Date(Number(ms) + 0.5);
+}
 
-export type BigIntStats = {
+export class Stats extends StatsBase {
+  constructor(
+    dev,
+    mode,
+    nlink,
+    uid,
+    gid,
+    rdev,
+    blksize,
+    ino,
+    size,
+    blocks,
+    atimeMs,
+    mtimeMs,
+    ctimeMs,
+    birthtimeMs,
+  ) {
+    super(
+      dev,
+      mode,
+      nlink,
+      uid,
+      gid,
+      rdev,
+      blksize,
+      ino,
+      size,
+      blocks,
+    );
+    this.atimeMs = atimeMs;
+    this.mtimeMs = mtimeMs;
+    this.ctimeMs = ctimeMs;
+    this.birthtimeMs = birthtimeMs;
+    this.atime = dateFromMs(atimeMs);
+    this.mtime = dateFromMs(mtimeMs);
+    this.ctime = dateFromMs(ctimeMs);
+    this.birthtime = dateFromMs(birthtimeMs);
+  }
+}
+
+export interface IBigIntStats {
   /** ID of the device containing the file.
    *
    * _Linux/Mac OS only._ */
@@ -159,10 +237,13 @@ export type BigIntStats = {
   isFile: () => boolean;
   isSocket: () => boolean;
   isSymbolicLink: () => boolean;
-};
+}
+
+export class BigIntStats {}
 
 export function convertFileInfoToStats(origin: Deno.FileInfo): Stats {
-  return {
+  const stats = ObjectCreate(Stats.prototype);
+  ObjectAssign(stats, {
     dev: origin.dev,
     ino: origin.ino,
     mode: origin.mode,
@@ -189,7 +270,9 @@ export function convertFileInfoToStats(origin: Deno.FileInfo): Stats {
     isSocket: () => false,
     ctime: origin.mtime,
     ctimeMs: origin.mtime?.getTime() || null,
-  };
+  });
+
+  return stats;
 }
 
 function toBigInt(number?: number | null) {
@@ -200,7 +283,8 @@ function toBigInt(number?: number | null) {
 export function convertFileInfoToBigIntStats(
   origin: Deno.FileInfo,
 ): BigIntStats {
-  return {
+  const stats = ObjectCreate(BigIntStats.prototype);
+  ObjectAssign(stats, {
     dev: toBigInt(origin.dev),
     ino: toBigInt(origin.ino),
     mode: toBigInt(origin.mode),
@@ -233,7 +317,8 @@ export function convertFileInfoToBigIntStats(
     ctime: origin.mtime,
     ctimeMs: origin.mtime ? BigInt(origin.mtime.getTime()) : null,
     ctimeNs: origin.mtime ? BigInt(origin.mtime.getTime()) * 1000000n : null,
-  };
+  });
+  return stats;
 }
 
 // shortcut for Convert File Info to Stats or BigIntStats
diff --git a/ext/node/polyfills/_fs/_fs_watch.ts b/ext/node/polyfills/_fs/_fs_watch.ts
index 2ba372e34..78903cd55 100644
--- a/ext/node/polyfills/_fs/_fs_watch.ts
+++ b/ext/node/polyfills/_fs/_fs_watch.ts
@@ -10,7 +10,6 @@ import { promisify } from "node:util";
 import { getValidatedPath } from "ext:deno_node/internal/fs/utils.mjs";
 import { validateFunction } from "ext:deno_node/internal/validators.mjs";
 import { stat, Stats } from "ext:deno_node/_fs/_fs_stat.ts";
-import { Stats as StatsClass } from "ext:deno_node/internal/fs/utils.mjs";
 import { Buffer } from "node:buffer";
 import { delay } from "ext:deno_node/_util/async.ts";
 
@@ -22,7 +21,7 @@ const statAsync = async (filename: string): Promise<Stats | null> => {
     return emptyStats;
   }
 };
-const emptyStats = new StatsClass(
+const emptyStats = new Stats(
   0,
   0,
   0,
diff --git a/ext/node/polyfills/fs.ts b/ext/node/polyfills/fs.ts
index 38a7a2bfb..bf43dd92e 100644
--- a/ext/node/polyfills/fs.ts
+++ b/ext/node/polyfills/fs.ts
@@ -69,7 +69,12 @@ import {
 } from "ext:deno_node/_fs/_fs_rename.ts";
 import { rmdir, rmdirPromise, rmdirSync } from "ext:deno_node/_fs/_fs_rmdir.ts";
 import { rm, rmPromise, rmSync } from "ext:deno_node/_fs/_fs_rm.ts";
-import { stat, statPromise, statSync } from "ext:deno_node/_fs/_fs_stat.ts";
+import {
+  stat,
+  statPromise,
+  Stats,
+  statSync,
+} from "ext:deno_node/_fs/_fs_stat.ts";
 import {
   symlink,
   symlinkPromise,
@@ -105,7 +110,6 @@ import {
   writeFilePromise,
   writeFileSync,
 } from "ext:deno_node/_fs/_fs_writeFile.ts";
-import { Stats } from "ext:deno_node/internal/fs/utils.mjs";
 // @deno-types="./internal/fs/streams.d.ts"
 import {
   createReadStream,
diff --git a/tests/unit_node/fs_test.ts b/tests/unit_node/fs_test.ts
index 4a8ef89f3..caa266ef2 100644
--- a/tests/unit_node/fs_test.ts
+++ b/tests/unit_node/fs_test.ts
@@ -9,6 +9,8 @@ import {
   mkdtempSync,
   promises,
   readFileSync,
+  Stats,
+  statSync,
   writeFileSync,
 } from "node:fs";
 import { constants as fsPromiseConstants, cp } from "node:fs/promises";
@@ -98,6 +100,15 @@ Deno.test(
 );
 
 Deno.test(
+  "[node/fs statSync] instanceof fs.Stats",
+  () => {
+    const stat = statSync("tests/testdata/assets/fixture.json");
+    assert(stat);
+    assert(stat instanceof Stats);
+  },
+);
+
+Deno.test(
   "[node/fs/promises cp] copy file",
   async () => {
     const src = mkdtempSync(join(tmpdir(), "foo-")) + "/test.txt";