invalid_platforms_field

The 'platforms' field must be a map with platforms as keys.

The analyzer produces this diagnostic when a top-level platforms field is specified, but its value is not a map with keys. To learn more about specifying your package's supported platforms, check out the documentation on platform declarations.

The following pubspec.yaml produces this diagnostic because platforms should be a map.

name: example
platforms:
  - android
  - web
  - ios

If you can rely on automatic platform detection, then omit the top-level platforms field.

name: example

If you need to manually specify the list of supported platforms, then write the platforms field as a map with platform names as keys.

name: example
platforms:
  android:
  web:
  ios: