Fix two review findings in spm Podfile reading and deinit output

- A multi-line `pod` call with a blank or comment line in the middle no
  longer ends early, so a pod sourced from node_modules/react-native is not
  reported as a non-React Native pod.
- `spm deinit` says to run `pod install` only when it removed the SwiftPM
  setup, and says `cd ios && pod install` when run from the JS root.

Author: chrfalch

packages/react-native/scripts/setup-apple-spm.js

@@ -779,7 +779,7 @@ function podfilePodNames(appRoot /*: string */) /*: Array<string> */ {
   for (const line of fs.readFileSync(podfilePath, 'utf8').split('\n')) {
     // `#{` is Ruby string interpolation, not a comment. A line that ends in
     // `,` continues on the next one.
-    const code = continued + line.split(/#(?!\{)/)[0].trimEnd();
+    const code = (continued + line.split(/#(?!\{)/)[0]).trimEnd();
     if (code.endsWith(',')) {
       continued = code + ' ';
     } else {
@@ -1154,10 +1154,10 @@ async function main(argv /*:: ?: Array<string> */) /*: Promise<void> */ {
     // removeSpmInjection drops the marker, and the record with it.
     const gitignoreRecord =
       xcodeprojPath != null ? readMarker(xcodeprojPath)?.gitignore : null;
-    if (
+    const removed =
       xcodeprojPath != null &&
-      removeSpmInjection({appRoot, xcodeprojPath}).status === 'removed'
-    ) {
+      removeSpmInjection({appRoot, xcodeprojPath}).status === 'removed';
+    if (removed && xcodeprojPath != null) {
       log(`Removed SPM packages from ${path.basename(xcodeprojPath)}.`);
     } else {
       log('No SPM injection found — nothing to remove.');
@@ -1170,8 +1170,12 @@ async function main(argv /*:: ?: Array<string> */) /*: Promise<void> */ {
           'Remove them by hand.',
       );
     }
-    if (fs.existsSync(path.join(appRoot, 'Podfile'))) {
-      log('To go back to CocoaPods, run `pod install`.');
+    if (removed && fs.existsSync(path.join(appRoot, 'Podfile'))) {
+      const podInstall =
+        appRoot === process.cwd()
+          ? 'pod install'
+          : `cd ${path.relative(process.cwd(), appRoot)} && pod install`;
+      log(`To go back to CocoaPods, run \`${podInstall}\`.`);
     }
     return;
   }

packages/react-native/scripts/spm/__tests__/setup-apple-spm-test.js

@@ -699,6 +699,20 @@ describe('podfilePodNames', () => {
     ).toEqual(['RNSVG', 'OCMock']);
   });
 
+  it('reads past blank and comment lines inside a continued pod statement', () => {
+    expect(
+      namesIn([
+        "  pod 'React-Core',",
+        '    # comment',
+        "    :path => '../node_modules/react-native/'",
+        "  pod 'React-RCTText',",
+        '',
+        "    :path => '../node_modules/react-native/Libraries/Text'",
+        "  pod 'OCMock', '~> 3.9.1'",
+      ]),
+    ).toEqual(['OCMock']);
+  });
+
   it('keeps pods whose names use Ruby interpolation', () => {
     expect(
       namesIn([
@@ -1027,6 +1041,29 @@ describe('CocoaPods conversion', () => {
       );
     });
 
+    it('does not mention `pod install` when it removed nothing', async () => {
+      fs.writeFileSync(podfilePath, STOCK_PODFILE);
+
+      await main(['deinit']);
+
+      expect(output(logSpy)).not.toContain('pod install');
+    });
+
+    it('says where to run `pod install` when run from the JS root', async () => {
+      const iosDir = path.join(appRoot, 'ios');
+      fs.mkdirSync(iosDir);
+      fs.writeFileSync(path.join(appRoot, 'package.json'), '{}');
+      mkXcodeproj(iosDir, 'MyApp.xcodeproj');
+      mkInjectedXcodeproj(iosDir, 'MyApp.xcodeproj');
+      fs.writeFileSync(path.join(iosDir, 'Podfile'), STOCK_PODFILE);
+
+      await main(['deinit']);
+
+      expect(output(logSpy)).toContain(
+        'To go back to CocoaPods, run `cd ios && pod install`.',
+      );
+    });
+
     it('still says to run `pod install` when removing an empty directory fails', async () => {
       mkInjectedProject();
       fs.mkdirSync(path.join(appRoot, 'ReactNativeSPM', 'Scripts'), {