package is forbidden but only when it's imported - flutter

Question

Here's an error I'm getting when trying to save the pubspec.yaml (which automatically runs flutter pub get) (I changed the names of the packages):
Running "flutter pub get" in ravencoin_front...
Because every version of package_b from path depends on
package_c any which is forbidden, package_b from path is
forbidden. So, because package_a depends on package_b from
path, version solving failed. pub get failed (server unavailable) --
attempting retry 1 in 1 seconds...
So the question is, why is package_c forbidden? Here's what package_c looks like:
pubspec.yaml:
name: package_c
version: 1.0.0
description: Serverpod client for communication to the consent server and database.
homepage: https://github.com/.../package_c
environment:
sdk: '>=2.12.0 <3.0.0'
dependencies:
serverpod_client: ^0.9.8
/lib/package_c.dart
library package_c;
export 'package:package_c/src/protocol/protocol.dart';
export 'package:serverpod_client/serverpod_client.dart';
Finally here's protocol.dart:
/* AUTOMATICALLY GENERATED CODE DO NOT MODIFY */
/* To generate run: "serverpod generate" */
// ignore_for_file: public_member_api_docs
// ignore_for_file: unnecessary_import
library protocol;
// ignore: unused_import
import 'dart:typed_data';
import 'package:serverpod_client/serverpod_client.dart';
import 'consent_class.dart';
import 'consent_document_class.dart';
export 'consent_class.dart';
export 'consent_document_class.dart';
export 'client.dart';
class Protocol extends SerializationManager {
static final Protocol instance = Protocol();
final Map<String, constructor> _constructors = {};
#override
Map<String, constructor> get constructors => _constructors;
Protocol() {
constructors['Consent'] = (Map<String, dynamic> serialization) =>
Consent.fromSerialization(serialization);
constructors['ConsentDocument'] = (Map<String, dynamic> serialization) =>
ConsentDocument.fromSerialization(serialization);
}
}
There are no errors, not sure why this package is seen as "forbidden."
Now package_b also requires other pacakges and overrides their paths, and they work just fine. so at first I thought it doesn't like the "nested paths" part of this situation, but that's not it, otherwise it would complain about the others too.
I also wondered, maybe the issue is that it has two "library" listed in the files. but I don't think that's it because if I remove the library package_c; it has the same problem.
Maybe it's as simple as this package_c not being correctly setup as a package, but I think it is, I looked up the requirements and it seems to fit from what I found.
Just for good measure let me include some of package_b pubspect.yaml:
name: package_b
description: Ravencoin wallet backend library
version: 1.0.0
environment:
sdk: '>=2.12.0 <3.0.0'
dependencies:
...
package_d: ^4.0.1
...
package_c: ^1.0.0
dependency_overrides:
# causes error!
package_c:
path: ../../package_c
# works fine!
package_d:
path: ../../package_d
...
Now, Here's the really weird part. remember, package_a imports pacakge_b which imports package_c. Well, package_b works just fine, dart pub get works great. but when I run flutter pub get in package_a, the error at the top occurs. the weird thing is only package_a complains about package_c, package_b is fine with package_c... what?
I guess I should include part of the pubspec.yaml for package_a too, this is the one that causes the error:
name: package_a
description: Ravencoin wallet frontend
publish_to: 'none' # Remove this line if you wish to publish to pub.dev
version: 1.0.0+0
environment:
sdk: '>=2.14.0 <3.0.0'
dependencies:
...
flutter:
sdk: flutter
package_b: ^1.0.0
...
dependency_overrides:
package_b:
path: ../package_b
...
...