fix(config): make it clear that configure-test-app performs a reset

scripts/configure.mjs

@@ -108,6 +108,23 @@ export function mergeConfig(lhs, rhs) {
   };
 }
 
+/**
+ * Returns whether `react-native.config.js` needs to be updated.
+ * @param {string} configPath
+ * @returns {boolean}
+ */
+export function shouldUpdateReactNativeConfig(configPath, fs = nodefs) {
+  if (!fs.existsSync(configPath)) {
+    return true;
+  }
+
+  const config = readTextFile(configPath, fs);
+  return (
+    !/["'`]react-native-test-app["'`]/.test(config) ||
+    !config.includes("configureProjects")
+  );
+}
+
 /**
  * Sort the keys in specified object.
  * @param {Record<string, unknown>} obj
@@ -609,15 +626,14 @@ export function updatePackageManifest(
 
 /**
  * Writes all specified files to disk.
- * @param {Configuration["files"]} files
+ * @param {[string, string | FileCopy][]} files
  * @param {string} destination
  * @returns {Promise<void[]>}
  */
 export function writeAllFiles(files, destination, fs = nodefs.promises) {
   const options = { recursive: true, mode: 0o755 };
   return Promise.all(
-    Object.keys(files).map(async (filename) => {
-      const content = files[filename];
+    files.map(async ([filename, content]) => {
       if (!content) {
         return;
       }
@@ -665,8 +681,25 @@ export function configure(params, fs = nodefs) {
   }
 
   const { files, oldFiles } = config;
+  const templateFiles = Object.entries(files).filter(([filename]) => {
+    switch (filename) {
+      case "react-native.config.js": {
+        const configPath = path.join(packagePath, filename);
+        const needsUpdate = shouldUpdateReactNativeConfig(configPath);
+        if (!needsUpdate) {
+          warn(
+            `skipped modifying '${filename}' because it may already be configured for 'react-native-test-app'`
+          );
+        }
+        return needsUpdate;
+      }
+
+      default:
+        return true;
+    }
+  });
 
-  writeAllFiles(files, packagePath).then(() => {
+  writeAllFiles(templateFiles, packagePath).then(() => {
     const packageManifest = path.join(packagePath, "package.json");
     if (!fs.existsSync(packageManifest)) {
       // We cannot assume that the app itself is an npm package. Some libraries

test/android/gradle.ts

@@ -73,7 +73,7 @@ async function makeProject(
     init: true,
   });
 
-  await writeAllFiles(files, packagePath);
+  await writeAllFiles(Object.entries(files), packagePath);
 
   try {
     await fsp.symlink(

test/configure/shouldUpdateReactNativeConfig.test.ts

@@ -0,0 +1,57 @@
+import { ok } from "node:assert/strict";
+import { afterEach, describe, it } from "node:test";
+import { shouldUpdateReactNativeConfig as shouldUpdateReactNativeConfigActual } from "../../scripts/configure.mjs";
+import { fs, setMockFiles } from "../fs.mock.js";
+
+describe("shouldUpdateReactNativeConfig()", () => {
+  const rnConfigFile = "react-native.config.js";
+
+  const shouldUpdateReactNativeConfig = () =>
+    shouldUpdateReactNativeConfigActual(rnConfigFile, fs);
+
+  afterEach(() => setMockFiles());
+
+  it("returns true if `react-native.config.js` does not exist", () => {
+    ok(shouldUpdateReactNativeConfig());
+  });
+
+  it("returns true if `react-native.config.js` is not configured", () => {
+    setMockFiles({ [rnConfigFile]: "module.exports = {};" });
+
+    ok(shouldUpdateReactNativeConfig());
+  });
+
+  it("returns true if `react-native-test-app` is mentioned but not used", () => {
+    setMockFiles({
+      [rnConfigFile]: `// TODO: Use 'react-native-test-app'
+module.exports = {};
+`,
+    });
+
+    ok(shouldUpdateReactNativeConfig());
+  });
+
+  it("returns false if `react-native-test-app` is configured", () => {
+    setMockFiles({
+      [rnConfigFile]: `const { configureProjects } = require("react-native-test-app");
+module.exports = {
+  project: configureProjects({
+    android: {
+      sourceDir: "android",
+    },
+    ios: {
+      sourceDir: "ios",
+    },
+  }),
+  dependencies: {
+    MyPackage: {
+      root: require("node:path").dirname(__dirname),
+    },
+  },
+};
+`,
+    });
+
+    ok(!shouldUpdateReactNativeConfig());
+  });
+});

test/configure/writeAllFiles.test.ts

@@ -17,11 +17,11 @@ describe("writeAllFiles()", () => {
   it("writes all files to disk", async () => {
     setMockFiles({ "file-on-disk": "0" });
     await writeAllFiles(
-      {
-        file0: { source: "file-on-disk" },
-        file1: "1",
-        file2: "2",
-      },
+      [
+        ["file0", { source: "file-on-disk" }],
+        ["file1", "1"],
+        ["file2", "2"],
+      ],
       "test"
     );
 
@@ -32,11 +32,11 @@ describe("writeAllFiles()", () => {
 
   it("ignores files with no content", async () => {
     await writeAllFiles(
-      {
-        file1: "1",
-        file2: "2",
-        file3: "",
-      },
+      [
+        ["file1", "1"],
+        ["file2", "2"],
+        ["file3", ""],
+      ],
       "."
     );
 
@@ -48,25 +48,23 @@ describe("writeAllFiles()", () => {
   it("rethrows write exceptions", async () => {
     await rejects(
       writeAllFiles(
-        {
-          file0: {
-            // This entry will throw an exception
-            source: "Bad Arnold movies.txt",
-          },
-          file1: "1",
-          file2: "2",
-        },
+        [
+          // This entry will throw an exception
+          ["file0", { source: "Bad Arnold movies.txt" }],
+          ["file1", "1"],
+          ["file2", "2"],
+        ],
         "."
       )
     );
 
     await rejects(
       writeAllFiles(
-        {
-          file1: "1",
-          file2: "2",
-          "": "3", // This entry will throw an exception
-        },
+        [
+          ["file1", "1"],
+          ["file2", "2"],
+          ["", "3"], // This entry will throw an exception
+        ],
         "."
       )
     );