Handle PSD files that do not have a readable Global Layer Mask Info block after LayerInfo.

packages/psd/src/sections/LayerAndMaskInformation/index.ts

@@ -57,7 +57,7 @@ export function parseLayerAndMaskInformation(
 
   // Skip over Global layer mask info
   // https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_17115
-  cursor.pass(cursor.read("u32"));
+  skipGlobalLayerMaskInfo(cursor);
 
   const globalAdditionalLayerInformation = readGlobalAdditionalLayerInformation(
     cursor,
@@ -140,3 +140,22 @@ export function parseLayerAndMaskInformation(
 
   return {layers, groups, orders, globalAdditionalLayerInformation};
 }
+
+function skipGlobalLayerMaskInfo(cursor: Cursor): void {
+  // Some PSD writers omit the Global Layer Mask Info block entirely and leave
+  // only alignment padding after LayerInfo. In those cases, treat the block as
+  // empty instead of forcing a 4-byte length read past the end of the section.
+  if (cursor.position + 4 > cursor.length) {
+    return;
+  }
+
+  const length = cursor.read("u32");
+  const remaining = cursor.length - cursor.position;
+
+  if (length > remaining) {
+    cursor.unpass(4);
+    return;
+  }
+
+  cursor.pass(length);
+}

packages/psd/src/sections/LayerAndMaskInformation/readLayerRecordsAndChannels.ts

@@ -216,7 +216,7 @@ export function readGlobalAdditionalLayerInformation(
   fileVersionSpec: FileVersionSpec
 ): AdditionalLayerProperties {
   const additionalLayerInfos = [];
-  while (cursor.position < cursor.length) {
+  while (cursor.position + 12 <= cursor.length) {
     try {
       additionalLayerInfos.push(
         readAdditionalLayerInfo(cursor, fileVersionSpec, /* padding */ 4)

packages/psd/tests/integration/procreateMissingGlobalMaskInfo.test.ts

@@ -0,0 +1,29 @@
+// @webtoon/psd
+// Copyright 2021-present NAVER WEBTOON
+// MIT License
+
+import * as fs from "fs";
+import * as path from "path";
+import {beforeAll, describe, expect, it} from "vitest";
+
+import type Psd from "../../src/index";
+import PSD from "../../src/index";
+
+const FIXTURE_DIR = path.join(__dirname, "fixtures");
+
+describe("Procreate PSD without global mask info", () => {
+  let psd: Psd;
+
+  beforeAll(() => {
+    const data = fs.readFileSync(
+      path.resolve(FIXTURE_DIR, "procreate-missing-global-mask-info.psd")
+    );
+    psd = PSD.parse(data.buffer);
+  });
+
+  it("parses successfully", () => {
+    expect(psd.width).toBe(128);
+    expect(psd.height).toBe(128);
+    expect(psd.layers.length).toBeGreaterThan(0);
+  });
+});

packages/psd/tests/unit/layerAndMaskInformation.test.ts

@@ -0,0 +1,37 @@
+// @webtoon/psd
+// Copyright 2021-present NAVER WEBTOON
+// MIT License
+
+import {describe, expect, it} from "vitest";
+
+import {PsdSpec} from "../../src/interfaces/FileVersionSpec";
+import {parseLayerAndMaskInformation} from "../../src/sections/LayerAndMaskInformation";
+
+describe("parseLayerAndMaskInformation", () => {
+  it("accepts PSD sections without a readable global layer mask info block", () => {
+    const data = new Uint8Array([
+      0x00,
+      0x00,
+      0x00,
+      0x08, // Layer and Mask Information section length
+      0x00,
+      0x00,
+      0x00,
+      0x02, // LayerInfo length
+      0x00,
+      0x00, // layer count = 0
+      0x00,
+      0x00, // alignment padding; no room for GlobalLayerMaskInfo length field
+    ]);
+
+    const section = parseLayerAndMaskInformation(
+      new DataView(data.buffer),
+      PsdSpec
+    );
+
+    expect(section.layers).toStrictEqual([]);
+    expect(section.groups).toStrictEqual([]);
+    expect(section.orders).toStrictEqual([]);
+    expect(section.globalAdditionalLayerInformation).toStrictEqual({});
+  });
+});