From 5fd17bccff2e57b043cb56ec703ea2f385ee7c98 Mon Sep 17 00:00:00 2001
From: Srivats Venkataraman <42980667+srivats22@users.noreply.github.com>
Date: Mon, 28 Apr 2025 09:19:00 -0400
Subject: [PATCH] Changes message when web folder is not present (#165084)
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This PR addresses: https://github.com/flutter/flutter/issues/164921

The old message for when the web folder wasnt present and a build for
web command was executed the following message was thrown:
```Missing index.html.```

The new message is going to be:

```Run flutter create . --platforms web```

<img width="1087" alt="Screenshot 2025-03-12 at 5 16 15 PM"
src="https://github.com/user-attachments/assets/0676083e-03a5-4bea-afac-8321eb9358f9"
/>
<img width="1440" alt="Screenshot 2025-03-12 at 5 33 15 PM"
src="https://github.com/user-attachments/assets/4eab879c-23d8-4bd0-b08a-a5728009a943"
/>

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we expect every widget to implement].
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above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
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---
 .../lib/src/commands/build_web.dart           |  5 ++-
 .../hermetic/build_web_test.dart              | 37 ++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/packages/flutter_tools/lib/src/commands/build_web.dart b/packages/flutter_tools/lib/src/commands/build_web.dart
index 091e676d098..6fdca627530 100644
--- a/packages/flutter_tools/lib/src/commands/build_web.dart
+++ b/packages/flutter_tools/lib/src/commands/build_web.dart
@@ -217,7 +217,10 @@ class BuildWebCommand extends BuildSubCommand {
       );
     }
     if (!project.web.existsSync()) {
-      throwToolExit('Missing index.html.');
+      throwToolExit(
+        'This project is not configured for the web.\n'
+        'To configure this project for the web, run flutter create . --platforms web',
+      );
     }
     if (!_fileSystem.currentDirectory
             .childDirectory('web')
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart
index 01f7fa1583b..509a6e37f71 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart
@@ -64,7 +64,11 @@ void main() {
 
       expect(
         () => runner.run(<String>['build', 'web', '--no-pub']),
-        throwsToolExit(message: 'Missing index.html.'),
+        throwsToolExit(
+          message:
+              'This project is not configured for the web.\n'
+              'To configure this project for the web, run flutter create . --platforms web',
+        ),
       );
     },
     overrides: <Type, Generator>{
@@ -588,6 +592,37 @@ void main() {
       ProcessManager: () => processManager,
     },
   );
+
+  testUsingContext(
+    'Refuses to build for web when folder is missing',
+    () async {
+      fileSystem.file(fileSystem.path.join('web')).deleteSync(recursive: true);
+      final CommandRunner<void> runner = createTestCommandRunner(
+        BuildCommand(
+          androidSdk: FakeAndroidSdk(),
+          buildSystem: TestBuildSystem.all(BuildResult(success: true)),
+          fileSystem: fileSystem,
+          logger: logger,
+          osUtils: FakeOperatingSystemUtils(),
+        ),
+      );
+
+      expect(
+        () => runner.run(<String>['build', 'web', '--no-pub']),
+        throwsToolExit(
+          message:
+              'This project is not configured for the web.\n'
+              'To configure this project for the web, run flutter create . --platforms web',
+        ),
+      );
+    },
+    overrides: <Type, Generator>{
+      Platform: () => fakePlatform,
+      FileSystem: () => fileSystem,
+      FeatureFlags: () => TestFeatureFlags(isWebEnabled: true),
+      ProcessManager: () => processManager,
+    },
+  );
 }
 
 void setupFileSystemForEndToEndTest(FileSystem fileSystem) {