feat: allow templates to be executable files (#41)

Allows you to `chmod +x` a template file, making it executable. Then
when templating the file, the resulting file will also be executable.

src/templates.test.ts

@@ -1,9 +1,8 @@
 import { existsSync } from "fs";
-import { readFile, mkdtemp, rm } from "fs/promises";
+import { readFile, mkdtemp, rm, stat } from "fs/promises";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { join, resolve } from "path";
 import { tmpdir } from "os";
-import { v4 as uuid } from "uuid";
 
 import { Config } from "./config";
 import { templateFiles } from "./templates";
@@ -86,4 +85,12 @@ This file will only be templated if the \`NO_MARKDOWN\` environment variable is
     const fileExists = existsSync(path);
     expect(fileExists).toBe(false);
   });
+
+  it<LocalTestContext>("will use the same file permissions as the template", async (ctx) => {
+    await templateFiles(ctx.config);
+    const path = join(ctx.config.fullPath, "executable.sh");
+    const stats = await stat(path);
+
+    expect(stats.mode.toString(8)).toBe("100755");
+  });
 });

src/templates.ts

@@ -1,6 +1,6 @@
 import * as core from "@actions/core";
 import * as glob from "@actions/glob";
-import { open, readFile, writeFile } from "fs/promises";
+import { chmod, open, readFile, stat, writeFile } from "fs/promises";
 import { dirname, join, relative } from "path";
 import { mkdirP } from "@actions/io";
 
@@ -20,6 +20,7 @@ export async function templateFiles(config: Config): Promise<void> {
     core.info(`Template ${relativePath}`);
 
     try {
+      const templateStats = await stat(templatePath);
       const templateData = await readFile(templatePath, "utf8");
       const templateHandlebar = Handlebars.compile(templateData);
       const fileData = templateHandlebar(config.templateVariables);
@@ -33,6 +34,10 @@ export async function templateFiles(config: Config): Promise<void> {
       const io = await open(writePath, "a");
       await io.close();
       await writeFile(writePath, fileData);
+      await chmod(
+        writePath,
+        "0" + (templateStats.mode & parseInt("777", 8)).toString(8),
+      );
 
       core.debug("File written.");
     } catch (err) {

test/fixtures/templates/executable.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env
+
+echo "This is an executable script."