fix(e2e): bound kitchen sink failure logs

scripts/e2e/lib/kitchen-sink-plugin/assertions.mjs

@@ -14,6 +14,10 @@ const LOG_SCAN_MAX_FILES = 5000;
 const LOG_SCAN_MAX_FINDINGS = 100;
 const LOG_SCAN_MAX_LINE_CHARS = 16 * 1024;
 const LOG_SCAN_SEGMENT_OVERLAP_CHARS = 256;
+const EXPECT_FAILURE_OUTPUT_MAX_BYTES = readPositiveIntEnv(
+  "KITCHEN_SINK_EXPECT_FAILURE_OUTPUT_MAX_BYTES",
+  1024 * 1024,
+);
 
 const readJson = (file) => JSON.parse(fs.readFileSync(file, "utf8"));
 const scratchFile = (name) => path.join(scratchRoot, name);
@@ -45,9 +49,21 @@ function resolveHomePath(value) {
   return value;
 }
 
+function readTextFileBounded(file, maxBytes, label) {
+  const stats = fs.statSync(file);
+  if (stats.size > maxBytes) {
+    throw new Error(`${label} exceeded ${maxBytes} bytes: ${file} (${stats.size} bytes)`);
+  }
+  return fs.readFileSync(file, "utf8");
+}
+
 function expectFailure() {
   const outputFile = process.argv[3];
-  const output = fs.readFileSync(outputFile, "utf8");
+  const output = readTextFileBounded(
+    outputFile,
+    EXPECT_FAILURE_OUTPUT_MAX_BYTES,
+    "expected failure output",
+  );
   const source = process.env.KITCHEN_SINK_SOURCE;
   const spec = process.env.KITCHEN_SINK_SPEC;
   const displayedSpec = source === "npm" ? spec.replace(/^npm:/u, "") : spec;

test/scripts/kitchen-sink-plugin-assertions.test.ts

@@ -222,6 +222,33 @@ function runSweepShell(script: string, env: NodeJS.ProcessEnv = {}) {
 }
 
 describe("kitchen-sink plugin assertions", () => {
+  it("bounds expected-failure output before matching failure diagnostics", () => {
+    const scratchRoot = mkdtempSync(path.join(tmpdir(), "openclaw-kitchen-sink-failure-cap-"));
+    const outputPath = path.join(scratchRoot, "expected-failure.log");
+    try {
+      writeFileSync(outputPath, "x".repeat(128));
+
+      const result = spawnSync(
+        process.execPath,
+        [ASSERTIONS_SCRIPT, "expect-failure", outputPath],
+        {
+          encoding: "utf8",
+          env: {
+            ...process.env,
+            KITCHEN_SINK_EXPECT_FAILURE_OUTPUT_MAX_BYTES: "64",
+            KITCHEN_SINK_SOURCE: "npm",
+            KITCHEN_SINK_SPEC: "npm:@openclaw/kitchen-sink@0.0.0",
+          },
+        },
+      );
+
+      expect(result.status).not.toBe(0);
+      expect(result.stderr).toContain("expected failure output exceeded 64 bytes");
+    } finally {
+      rmSync(scratchRoot, { force: true, recursive: true });
+    }
+  });
+
   it("fails full-surface installs when stable diagnostic canaries disappear", () => {
     const result = runAssertInstalled();