Exceptions

Dependy can throw several exceptions during its operation. Understanding when these exceptions occur will help us handle errors gracefully in our application.

DependyCircularDependencyException

This exception is thrown when there is a circular dependency in the provider graph. A circular dependency occurs when two or more providers depend on each other directly or indirectly, leading to an infinite loop during resolution.

Example: If Service-A depends on Service-B, Service-B depends on Service-C, and Service-C depends on Service-A. This indirect chain of dependencies leads to an infinite loop during resolution.

DependyModuleDisposedException

This exception is thrown when we attempt to resolve a provider from a DependyModule that has already been disposed. Once a module is disposed, it can no longer provide instances of its services.

Example: If we call module<SomeService>() after calling module.dispose(), a DependyModuleDisposedException will be raised.

DependyProviderNotFoundException

This exception occurs when we try to resolve a provider for a specific type, but no provider is registered for that type within the module or its submodules.

Example: If we attempt to get an instance of Provider C but it has not been defined in the current module or any of its submodules, a DependyProviderNotFoundException will be thrown.

DependyProviderMissingDependsOnException

This exception is thrown when a provider tries to resolve a dependency that has not been declared in its dependsOn set. This verifies that all dependencies are explicitly defined, promoting better design and avoiding runtime errors.

Example: If Provider D requires Provider E, but Provider E is not listed in the dependsOn set of Provider D, a DependyProviderMissingDependsOnException will occur.

DependyProviderDisposedException

This exception is thrown when we try to use a provider that has already been disposed. Once a provider is disposed, it cannot be used anymore.

Example: If we call <module><T>() on a disposed provider, a DependyProviderDisposedException will be raised.

DependyDuplicateProviderException

This exception is thrown when there is more than one provider of the same type registered within a single module.

Example:

final databaseModule = DependyModule(
  providers: {
    DependyProvider<DatabaseService>(
          (_) => SqlDatabaseService(),
    ),
    DependyProvider<DatabaseService>(
          (_) => SqliteDatabaseService(),
    ),
  },
);

In this example, both SqlDatabaseService and SqliteDatabaseService are registered as providers for the DatabaseService type within the same module.

---