fix(coding-agent): enforce safe auto-resized image limits closes #2055

packages/coding-agent/test/image-processing.test.ts

@@ -52,12 +52,13 @@ describe("resizeImage", () => {
 			{ maxWidth: 100, maxHeight: 100, maxBytes: 1024 * 1024 },
 		);
 
-		expect(result.wasResized).toBe(false);
-		expect(result.data).toBe(TINY_PNG);
-		expect(result.originalWidth).toBe(2);
-		expect(result.originalHeight).toBe(2);
-		expect(result.width).toBe(2);
-		expect(result.height).toBe(2);
+		expect(result).not.toBeNull();
+		expect(result!.wasResized).toBe(false);
+		expect(result!.data).toBe(TINY_PNG);
+		expect(result!.originalWidth).toBe(2);
+		expect(result!.originalHeight).toBe(2);
+		expect(result!.width).toBe(2);
+		expect(result!.height).toBe(2);
 	});
 
 	it("should resize image exceeding dimension limits", async () => {
@@ -66,26 +67,38 @@ describe("resizeImage", () => {
 			{ maxWidth: 50, maxHeight: 50, maxBytes: 1024 * 1024 },
 		);
 
-		expect(result.wasResized).toBe(true);
-		expect(result.originalWidth).toBe(100);
-		expect(result.originalHeight).toBe(100);
-		expect(result.width).toBeLessThanOrEqual(50);
-		expect(result.height).toBeLessThanOrEqual(50);
+		expect(result).not.toBeNull();
+		expect(result!.wasResized).toBe(true);
+		expect(result!.originalWidth).toBe(100);
+		expect(result!.originalHeight).toBe(100);
+		expect(result!.width).toBeLessThanOrEqual(50);
+		expect(result!.height).toBeLessThanOrEqual(50);
 	});
 
 	it("should resize image exceeding byte limit", async () => {
 		const originalBuffer = Buffer.from(LARGE_PNG_200x200, "base64");
 		const originalSize = originalBuffer.length;
 
-		// Set maxBytes to less than the original image size
+		// Set maxBytes to less than the original encoded image size
 		const result = await resizeImage(
 			{ type: "image", data: LARGE_PNG_200x200, mimeType: "image/png" },
-			{ maxWidth: 2000, maxHeight: 2000, maxBytes: Math.floor(originalSize / 2) },
+			{ maxWidth: 2000, maxHeight: 2000, maxBytes: Math.floor(LARGE_PNG_200x200.length * 0.9) },
 		);
 
 		// Should have tried to reduce size
-		const resultBuffer = Buffer.from(result.data, "base64");
+		expect(result).not.toBeNull();
+		const resultBuffer = Buffer.from(result!.data, "base64");
 		expect(resultBuffer.length).toBeLessThan(originalSize);
+		expect(result!.data.length).toBeLessThan(LARGE_PNG_200x200.length);
+	});
+
+	it("should return null when image cannot be resized below maxBytes", async () => {
+		const result = await resizeImage(
+			{ type: "image", data: LARGE_PNG_200x200, mimeType: "image/png" },
+			{ maxWidth: 2000, maxHeight: 2000, maxBytes: 1 },
+		);
+
+		expect(result).toBeNull();
 	});
 
 	it("should handle JPEG input", async () => {
@@ -94,9 +107,10 @@ describe("resizeImage", () => {
 			{ maxWidth: 100, maxHeight: 100, maxBytes: 1024 * 1024 },
 		);
 
-		expect(result.wasResized).toBe(false);
-		expect(result.originalWidth).toBe(2);
-		expect(result.originalHeight).toBe(2);
+		expect(result).not.toBeNull();
+		expect(result!.wasResized).toBe(false);
+		expect(result!.originalWidth).toBe(2);
+		expect(result!.originalHeight).toBe(2);
 	});
 });
 

packages/coding-agent/test/image-resize-callers.test.ts

@@ -0,0 +1,53 @@
+import { mkdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("../src/utils/image-resize.js", () => ({
+	resizeImage: vi.fn(),
+	formatDimensionNote: vi.fn(() => undefined),
+}));
+
+import { processFileArguments } from "../src/cli/file-processor.js";
+import { createReadTool } from "../src/core/tools/read.js";
+import { resizeImage } from "../src/utils/image-resize.js";
+
+const TINY_PNG_BASE64 =
+	"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg==";
+
+describe("image resize callers", () => {
+	let testDir: string;
+
+	beforeEach(() => {
+		testDir = join(tmpdir(), `image-resize-callers-${Date.now()}`);
+		mkdirSync(testDir, { recursive: true });
+		vi.mocked(resizeImage).mockReset();
+		vi.mocked(resizeImage).mockResolvedValue(null);
+	});
+
+	afterEach(() => {
+		rmSync(testDir, { recursive: true, force: true });
+	});
+
+	it("read tool returns text-only output when auto-resize cannot produce a safe image", async () => {
+		const imagePath = join(testDir, "test.png");
+		writeFileSync(imagePath, Buffer.from(TINY_PNG_BASE64, "base64"));
+
+		const tool = createReadTool(testDir);
+		const result = await tool.execute("test-read-image", { path: imagePath });
+
+		expect(result.content).toHaveLength(1);
+		expect(result.content[0].type).toBe("text");
+		expect((result.content[0] as { type: "text"; text: string }).text).toContain("Image omitted");
+	});
+
+	it("file processor omits image attachments when auto-resize cannot produce a safe image", async () => {
+		const imagePath = join(testDir, "test.png");
+		writeFileSync(imagePath, Buffer.from(TINY_PNG_BASE64, "base64"));
+
+		const result = await processFileArguments([imagePath]);
+
+		expect(result.images).toHaveLength(0);
+		expect(result.text).toContain("Image omitted");
+	});
+});