"flutter" tool poorly handles there being a file called "build" in the project directory

[DaveShuckerow]

If a project directory contains a file named 'build', there will be a name collision with Flutter's build directory.

To my understanding, there also exists a system-level configuration to specify the name of the build directory, but this would be impractical to configure on a team with a large number of people switching between projects based out of different version control systems.

Is there or can there be a way to avoid this name collision on a project scale?

(if you would like additional clarification, feel free to ping me)

[cbracken]

For reference, the user-level config is to set a value for build-dir in the ~/.flutter_settings (JSON format) config file; e.g.:

{"build-dir": "out"}

One option would be to support a project-level output dir in flutter.yaml, defaulted to the current default value build. Most of what's in there today describes build inputs (assets, configuration) rather than build outputs, but if this seems generally useful enough, it'd be a relatively small change.

[eseidelGoogle]

As noted in #6064, mostly our error handling in this case is poor. FYI @danrubel

[eseidelGoogle]

Our failure mode is still pretty bad. If you rm -rf build && touch build before flutter run we print this and then hang:

Launching lib/main.dart on iPhone 6s in debug mode...
Exception from flutter run: FileSystemException: Creation failed, path = 'build' (OS Error: Not a directory, errno = 20)
dart:io                                                   _Directory.createSync
package:file/src/forwarding/forwarding_directory.dart 15  _LocalFileSystemEntity&ForwardingDirectory.createSync
package:flutter_tools/src/base/file_system.dart 29        ensureDirectoryExists
package:flutter_tools/src/flx.dart 162                    assemble.<async>
dart:async                                                _SyncCompleter.complete
package:flutter_tools/src/asset.dart 148                  AssetBundle.build.<async>
dart:async                                                _SyncCompleter.complete
package:flutter_tools/src/asset.dart 294                  _obtainLicenses.<async>
===== asynchronous gap ===========================
dart:async                                                _Completer.completeError
package:flutter_tools/src/flx.dart 169                    assemble.<async>
dart:async                                                _SyncCompleter.complete
package:flutter_tools/src/asset.dart 148                  AssetBundle.build.<async>
dart:async                                                _SyncCompleter.complete
package:flutter_tools/src/asset.dart 294                  _obtainLicenses.<async>
===== asynchronous gap ===========================
dart:async                                                _asyncThenWrapperHelper
package:flutter_tools/src/flx.dart                        assemble
package:flutter_tools/src/flx.dart 113                    build.<async>
===== asynchronous gap ===========================
dart:async                                                Future.Future.microtask
package:flutter_tools/src/flx.dart                        build
package:flutter_tools/src/ios/simulators.dart 527         IOSSimulator._sideloadUpdatedAssetsForInstalledApplicationBundle
package:flutter_tools/src/ios/simulators.dart 502         IOSSimulator._setupUpdatedApplicationBundle.<async>
===== asynchronous gap ===========================
dart:async                                                Future.Future.microtask
package:flutter_tools/src/ios/simulators.dart             IOSSimulator._setupUpdatedApplicationBundle
package:flutter_tools/src/ios/simulators.dart 426         IOSSimulator.startApp.<async>
===== asynchronous gap ===========================
dart:async                                                Future.Future.microtask
package:flutter_tools/src/ios/simulators.dart             IOSSimulator.startApp
package:flutter_tools/src/run_hot.dart 161                HotRunner._run.<async>
dart:async                                                _SyncCompleter.complete
package:flutter_tools/src/resident_runner.dart 185        ResidentRunner.startEchoingDeviceLog.<async>
===== asynchronous gap ===========================
dart:async                                                _asyncThenWrapperHelper
package:flutter_tools/src/run_hot.dart                    HotRunner._run
package:flutter_tools/src/run_hot.dart 78                 HotRunner.run.<fn>
package:stack_trace                                       Chain.capture
package:flutter_tools/src/run_hot.dart 77                 HotRunner.run
package:flutter_tools/src/commands/run.dart 278           RunCommand.runCommand.<async>

[cbracken]

Giant stack trace should be fixed now (#7874).

[Hixie]

Now you get a giant dump from Gradle instead.

I think it's reasonable for us to reserve the "build" directory name, but we should handle the case of it being a file much better.