Invalid build.yaml in version 0.8.0 causes parse error during build_runner execution

[Nizlan]

Hi @ethanblake4,

I'm encountering a parse error when running build_runner in a Flutter project that depends on flutter_eval: ^0.8.0. This seems to stem from an invalid configuration in the package's build.yaml file, which appears to be an incomplete example snippet.

Steps to Reproduce:

• Add flutter_eval: ^0.8.0 to your pubspec.yaml under dependencies.
• Ensure you have build_runner installed.
• Run dart pub get to fetch dependencies.
• Run dart pub run build_runner build.

Error Log:

Building package executable... (2.0s)
Built build_runner:build_runner.

log output for build_runner
E Failed to parse build.yaml for flutter_eval: Invalid argument(s): line 6, column 7 of ../.pub-cache/hosted/pub.dev/flutter_eval-0.8.0/build.yaml:
Unsupported value for "builders". type 'Null' is not a subtype of type 'Map<dynamic, dynamic>' in type cast
╷
6 │       dart_eval_generator|member_count:
│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Problematic Code in build.yaml (from pub cache):

The file at ~/.pub-cache/hosted/pub.dev/flutter_eval-0.8.0/build.yaml contains:

texttargets:
  $default:
    builders:
      # Configure the builder pkg_name|builder_name
      # In this case, the member_count builder defined in ../example
      dart_eval_generator|member_count:

The last line is incomplete—it lacks a map value (e.g., enabled: true), causing the parse failure as it's treated as null. This error only occurs if build_runner is used in the project (e.g., for other code generation tasks like json_serializable or freezed). If not using build_runner, everything works fine, which might explain why it hasn't been reported yet.

[Treamz]

same problem for 0.8.1