Add import template into tui. Fix tests that fail on macos. Fix some updates.

src/utils/load-template-from-file.ts

@@ -0,0 +1,194 @@
+/**
+ * Loads template file contents for {@link Engine.importTemplate}.
+ *
+ * - `.json` files are read directly.
+ * - `.ts`, `.js`, `.mts`, `.cts`, `.mjs`, `.cjs` files are evaluated in a
+ *   short-lived child process and serialized to Extended JSON on stdout.
+ *   TypeScript templates (and the loader in dev) run via tsx; plain JS uses node.
+ */
+
+import { spawn } from "node:child_process";
+import { createRequire } from "node:module";
+import fs from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+/** Extensions loaded via subprocess module evaluation. */
+const MODULE_TEMPLATE_EXTENSIONS = new Set([
+  ".ts",
+  ".tsx",
+  ".mts",
+  ".cts",
+  ".js",
+  ".jsx",
+  ".mjs",
+  ".cjs",
+]);
+
+/** Maximum time allowed for a template module child process. */
+const MODULE_LOAD_TIMEOUT_MS = 30_000;
+
+/** Maximum stdout size from the loader child (50 MiB). */
+const MODULE_LOAD_MAX_BUFFER_BYTES = 50 * 1024 * 1024;
+
+/**
+ * Thrown when a template file cannot be read or loaded.
+ */
+export class TemplateLoadError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = "TemplateLoadError";
+  }
+}
+
+/**
+ * Resolves the tsx CLI binary shipped with this package.
+ */
+function resolveTsxCliPath(): string {
+  const require = createRequire(import.meta.url);
+  const tsxPackageJsonPath = require.resolve("tsx/package.json");
+  return path.join(path.dirname(tsxPackageJsonPath), "dist/cli.mjs");
+}
+
+/**
+ * Resolves the loader script path for dev (.ts) and production (.js) layouts.
+ */
+function resolveTemplateModuleLoaderPath(): string {
+  const directory = path.dirname(fileURLToPath(import.meta.url));
+  const compiledLoaderPath = path.join(directory, "template-module-loader.js");
+  if (fs.existsSync(compiledLoaderPath)) {
+    return compiledLoaderPath;
+  }
+
+  const sourceLoaderPath = path.join(directory, "template-module-loader.ts");
+  if (fs.existsSync(sourceLoaderPath)) {
+    return sourceLoaderPath;
+  }
+
+  throw new TemplateLoadError(
+    "Template module loader script was not found in the xo-cli package.",
+  );
+}
+
+/** TypeScript extensions that require tsx to evaluate the template module. */
+const TYPESCRIPT_TEMPLATE_EXTENSIONS = new Set([
+  ".ts",
+  ".tsx",
+  ".mts",
+  ".cts",
+]);
+
+/**
+ * Loads a TS/JS template module in an isolated child process.
+ * Returns Extended JSON suitable for {@link parseTemplate}.
+ */
+async function loadTemplateModuleViaChildProcess(
+  absolutePath: string,
+): Promise<string> {
+  const loaderPath = resolveTemplateModuleLoaderPath();
+  const extension = path.extname(absolutePath).toLowerCase();
+  const loaderIsTypeScript = loaderPath.endsWith(".ts");
+  const useTsx =
+    TYPESCRIPT_TEMPLATE_EXTENSIONS.has(extension) || loaderIsTypeScript;
+  const executable = useTsx ? resolveTsxCliPath() : process.execPath;
+  const args = [loaderPath, absolutePath];
+
+  return new Promise<string>((resolve, reject) => {
+    const child = spawn(executable, args, {
+      cwd: path.dirname(absolutePath),
+      stdio: ["ignore", "pipe", "pipe"],
+      env: process.env,
+    });
+
+    let stdout = "";
+    let stderr = "";
+    let stdoutBytes = 0;
+
+    const timeout = setTimeout(() => {
+      child.kill("SIGTERM");
+      reject(
+        new TemplateLoadError(
+          `Template module load timed out after ${MODULE_LOAD_TIMEOUT_MS / 1000}s`,
+        ),
+      );
+    }, MODULE_LOAD_TIMEOUT_MS);
+
+    child.stdout.on("data", (chunk: Buffer | string) => {
+      const text = typeof chunk === "string" ? chunk : chunk.toString("utf8");
+      stdoutBytes += Buffer.byteLength(text, "utf8");
+      if (stdoutBytes > MODULE_LOAD_MAX_BUFFER_BYTES) {
+        child.kill("SIGTERM");
+        reject(
+          new TemplateLoadError(
+            "Template module output exceeded the maximum allowed size.",
+          ),
+        );
+        return;
+      }
+      stdout += text;
+    });
+
+    child.stderr.on("data", (chunk: Buffer | string) => {
+      stderr += typeof chunk === "string" ? chunk : chunk.toString("utf8");
+    });
+
+    child.on("error", (error) => {
+      clearTimeout(timeout);
+      reject(
+        new TemplateLoadError(
+          `Failed to start template module loader: ${error.message}`,
+        ),
+      );
+    });
+
+    child.on("close", (code) => {
+      clearTimeout(timeout);
+
+      if (code !== 0) {
+        reject(
+          new TemplateLoadError(
+            stderr.trim() ||
+              `Template module loader exited with code ${code ?? "unknown"}`,
+          ),
+        );
+        return;
+      }
+
+      if (stdout.trim().length === 0) {
+        reject(new TemplateLoadError("Template module loader returned no output."));
+        return;
+      }
+
+      resolve(stdout);
+    });
+  });
+}
+
+/**
+ * Loads template contents from disk.
+ *
+ * @param filePath - Absolute or relative path to a JSON or module template file.
+ * @returns Extended JSON string for {@link Engine.importTemplate}.
+ */
+export async function loadTemplateFromFile(filePath: string): Promise<string> {
+  const absolutePath = path.resolve(filePath);
+
+  if (!fs.existsSync(absolutePath)) {
+    throw new TemplateLoadError(`Template file does not exist: ${absolutePath}`);
+  }
+
+  const extension = path.extname(absolutePath).toLowerCase();
+
+  if (extension === ".json") {
+    return fs.promises.readFile(absolutePath, "utf8");
+  }
+
+  if (MODULE_TEMPLATE_EXTENSIONS.has(extension)) {
+    return loadTemplateModuleViaChildProcess(absolutePath);
+  }
+
+  throw new TemplateLoadError(
+    `Unsupported template file extension "${extension}". ` +
+      "Use .json or a JavaScript/TypeScript module that exports an XOTemplate.",
+  );
+}