Suggest null-check patterns for type promo

[MaryaBelanger]

Fixes #5666

Staged: https://dart-dev--pr5679-null-check-wujb9sng.web.app/effective-dart/usage#consider-work-arounds-to-enable-type-promotion-for-nullable-fields

[dart-github-bot]

Visit the preview URL for this PR (updated for commit 77dbf0c):

https://dart-dev--pr5679-null-check-wujb9sng.web.app

[MaryaBelanger]

@parlough the effective dart toc isn't updating, something to do with style.md?

PathNotFoundException: Cannot open file, path = 'src/effective-dart/style.md' (OS Error: No such file or directory, errno = 2)
#0      _File.throwIfError (dart:io/file_impl.dart:675:7)
#1      _File.openSync (dart:io/file_impl.dart:490:5)
#2      _File.readAsBytesSync (dart:io/file_impl.dart:574:18)
#3      _File.readAsStringSync (dart:io/file_impl.dart:624:18)
#4      _File.readAsLinesSync (dart:io/file_impl.dart:630:36)
#5      _generateToc (package:dart_site/src/commands/generate_effective_dart_toc.dart:52:10)
#6      GenerateEffectiveDartToc.run (package:dart_site/src/commands/generate_effective_dart_toc.dart:36:36)
#7      CommandRunner.runCommand (package:args/command_runner.dart:212:27)
#8      CommandRunner.run.<anonymous closure> (package:args/command_runner.dart:122:25)
#9      new Future.sync (dart:async/future.dart:305:31)
#10     CommandRunner.run (package:args/command_runner.dart:122:14)
#11     main (file:///Users/mbelanger/Projects/dart.dev/dart-3/tool/dart_site/bin/dart_site.dart:23:22)
#12     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:295:33)
#13     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

I tried removing the path-base command on line 12 of style.md but still got the error (in case that's related)

Edit (by parlough): Fixed in 3dc225f :)

[atsansone]

@parlough the effective dart toc isn't updating, something to do with style.md?

PathNotFoundException: Cannot open file, path = 'src/effective-dart/style.md' (OS Error: No such file or directory, errno = 2)
#0      _File.throwIfError (dart:io/file_impl.dart:675:7)
#1      _File.openSync (dart:io/file_impl.dart:490:5)
#2      _File.readAsBytesSync (dart:io/file_impl.dart:574:18)
#3      _File.readAsStringSync (dart:io/file_impl.dart:624:18)
#4      _File.readAsLinesSync (dart:io/file_impl.dart:630:36)
#5      _generateToc (package:dart_site/src/commands/generate_effective_dart_toc.dart:52:10)
#6      GenerateEffectiveDartToc.run (package:dart_site/src/commands/generate_effective_dart_toc.dart:36:36)
#7      CommandRunner.runCommand (package:args/command_runner.dart:212:27)
#8      CommandRunner.run.<anonymous closure> (package:args/command_runner.dart:122:25)
#9      new Future.sync (dart:async/future.dart:305:31)
#10     CommandRunner.run (package:args/command_runner.dart:122:14)
#11     main (file:///Users/mbelanger/Projects/dart.dev/dart-3/tool/dart_site/bin/dart_site.dart:23:22)
#12     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:295:33)
#13     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

I tried removing the path-base command on line 12 of style.md but still got the error (in case that's related)

IIRC, all of the code is under src/content/<path>. The code for this command points there, so maybe your local copy doesn't have the latest version of the command? Just a thought.

[atsansone]

@MaryaBelanger : I would recommend a few updates to meet Google style. I note style guide entries as reference.

Thanks for this!