fix(release): handle large preparation diffs (#113760)

test/scripts/release-prepare.test.ts

@@ -1,3 +1,7 @@
+import { execFileSync } from "node:child_process";
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import path from "node:path";
 // Release prepare tests cover shadow planning, cutover commands, and candidate manifests.
 import { expectDefined } from "@openclaw/normalization-core";
 import { describe, expect, it, vi } from "vitest";
@@ -5,6 +9,7 @@ import {
   buildReleasePreparationManifest,
   createReleasePrepareSteps,
   parseReleasePrepareArgs,
+  readWorktreeState,
   runReleasePrepareStep,
   runReleasePrepareSteps,
 } from "../../scripts/release-prepare.ts";
@@ -159,6 +164,29 @@ describe("release preparation plan", () => {
 });
 
 describe("release preparation manifest", () => {
+  it("fingerprints generated diffs larger than Node's default child buffer", () => {
+    const rootDir = mkdtempSync(path.join(tmpdir(), "openclaw-release-prepare-"));
+    try {
+      execFileSync("git", ["init", "-q"], { cwd: rootDir });
+      execFileSync("git", ["config", "user.email", "release-test@openclaw.invalid"], {
+        cwd: rootDir,
+      });
+      execFileSync("git", ["config", "user.name", "OpenClaw Release Test"], { cwd: rootDir });
+      writeFileSync(path.join(rootDir, "package.json"), '{"version":"2026.7.2"}\n');
+      writeFileSync(path.join(rootDir, "generated.txt"), `${"a".repeat(2 * 1024 * 1024)}\n`);
+      execFileSync("git", ["add", "."], { cwd: rootDir });
+      execFileSync("git", ["commit", "-q", "-m", "test fixture"], { cwd: rootDir });
+      writeFileSync(path.join(rootDir, "generated.txt"), `${"b".repeat(2 * 1024 * 1024)}\n`);
+
+      const state = readWorktreeState(rootDir);
+
+      expect(state.changedFiles).toEqual(["generated.txt"]);
+      expect(state.fingerprint).toMatch(/^[0-9a-f]{64}$/u);
+    } finally {
+      rmSync(rootDir, { force: true, recursive: true });
+    }
+  });
+
   it("binds the plan to the exact source and worktree fingerprint", () => {
     const steps = runReleasePrepareSteps({
       cwd: "/repo",