How do I solve "Flutter build_runner FileException errorno = 3" error?

Question

Can you please help me fix the issue related to build_runner. On running command "flutter packages pub run build_runner watch --delete-conflicting-outputs", I get FileException errorno = 3 error.

I suspect this is a windows issue. Because the path generated in the error message is in lower case ('c:\users\xxxx\git-dev\flutter\xxx\xxxx\xxxx*'), whereas the actual path ('C:\Users\xxxx\git-dev\Flutter\xxx\xxxx\xxxx*') has a few uppercase characters.

[INFO] Generating build script...
[INFO] Generating build script completed, took 414ms

[INFO] Setting up file watchers...
[INFO] Setting up file watchers completed, took 11ms

[INFO] Waiting for all file watchers to be ready...

[SEVERE] Error from directory watcher for package:xxxxxx
If you see this consistently then it is recommended that you enable the polling file watcher with --use-polling-watcher.

You have hit a bug in build_runner

Please file an issue with reproduction steps at https://github.com/dart-enter code herelang/build/issues
     
FileSystemException: Directory listing failed, path =
'c:\users\xxxx\git-dev\flutter\xxx\xxxx\xxxx*' (OS Error: The system
cannot find the path specified., errno = 3)


Flutter doctor -v output is following:
[√] Flutter (Channel beta, 1.19.0-4.2.pre, on Microsoft Windows [Version 10.0.18363.900], locale en-IN)
• Flutter version 1.19.0-4.2.pre at C:\Users\xxxxxx\flutter
• Framework revision 9b9b543d92 (6 days ago), 2020-06-22 12:19:28 -0700
• Engine revision 9a28c3bcf4
• Dart version 2.9.0 (build 2.9.0-14.1.beta)

As suggested by message in the error,I used "flutter pub run build_runner watch --use-polling-watcher" command. However, I started getting another kind of error.

AssetNotFoundException: xxxx_xxxxx|.packages
package:build_runner_core/src/asset/file_based.dart 134:18 _fileForOrThrow.
dart:async _completeOnAsyncReturn
package:pool/pool.dart Pool.withResource
package:build_runner_core/src/asset/file_based.dart 133:26 _fileForOrThrow
package:build_runner_core/src/asset/file_based.dart 33:48 FileBasedAssetReader.readAsBytes
package:build_runner/src/generate/watch_impl.dart 326:52 WatchImpl._run.
package:build_runner/src/generate/watch_impl.dart WatchImpl._run.
package:build_runner/src/generate/watch_impl.dart 355:6 WatchImpl._run
package:build_runner/src/generate/watch_impl.dart 196:20 new WatchImpl
package:build_runner/src/generate/watch_impl.dart 127:5 _runWatch
package:build_runner/src/generate/watch_impl.dart 85:15 watch
dart:async _completeOnAsyncReturn
package:build_runner_core/src/generate/options.dart BuildOptions.create
dart:async _completeOnAsyncReturn
package:build_runner_core/src/package_graph/target_graph.dart TargetGraph.forPackageGraph
dart:async _completeOnAsyncReturn
package:build_runner_core/src/package_graph/target_graph.dart _packageBuildConfig
dart:async _completeOnAsyncReturn
package:build_config/src/build_config.dart BuildConfig.fromBuildConfigDir

Hi Christopher, I have updated the question to make it more readable. Basically, I need help in solving the issue related to "flutter packages pub run build_runner watch --delete-conflicting-outputs" command. — Prashant, Jun 30 '20 at 01:42
Not yet John. I created the issue on flutter sdk github page as well, but I got no resolution so far. — Prashant, Jul 03 '20 at 11:06

score 1 · Accepted Answer · answered Jul 04 '20 at 07:05

I figured out the issue and its resolution.

Because I am using "moor" package in my flutter application, I followed the instructions on their page (https://moor.simonbinder.eu/docs/using-sql/sql_ide/) to setup moor analyzer.

As soon as I added the following line in VSCode json settings:

"dart.additionalAnalyzerFileExtensions": ["moor"]

the command "flutter packages pub run build_runner watch --delete-conflicting-outputs" stopped working.

On removing the VSCode json setting, I was able to run build_runner command again.

How do I solve "Flutter build_runner FileException errorno = 3" error?

1 Answers1