Common errors

This page gathers the errors that show up most often when starting with Corvis, with their exact message and how to resolve them.

"Corvis can't resolve dependencies of the ..."

Corvis can't resolve dependencies of the CatsService (?, ConfigService). Please make sure that the
argument API_KEY at index [0] is available in the CatsModule context.

It appears at startup, when a provider or controller asks for something its module cannot see. The ? marks the missing argument, and the message names the token (API_KEY or the type name) and the module.

Common causes:

• The provider is in another module that does not export it, or that module is not in the imports of the one asking for it. A module only sees its own providers, the exports of its imports and those of the global modules. See Modules.
• A global module (#[module(global, ...)]) does not export the provider: global modules also have to export what they share.
• You asked for Arc<T> of a type that is not registered in the providers of any module.
• The token in #[inject("TOKEN")] does not match the one in Provider::use_value("TOKEN", ...).

If the dependency is optional, declare it as Option<Arc<T>>: you will receive None instead of the error.

"Corvis could not find X element"

Corvis could not find CatsService element (this provider does not exist in the current context)

It is returned by a programmatic lookup (app.get::<T>(), ModuleRef, ctx.get::<T>() inside a factory) when the token does not exist in the context being queried.

Circular dependencies

A circular dependency has been detected: AService -> BService -> AService. ...

Two providers ask for each other (directly or indirectly). The message suggests forwardRef(), but Corvis has no forwardRef: you have to break the cycle. Options:

• Extract the shared logic into a third provider that both depend on.
• Connect one of the sides with events (EventEmitter) instead of a direct call.
• Resolve the dependency lazily with ModuleRef (injecting module_ref: ModuleRef and calling self.module_ref.get::<T>() when needed, not in the constructor).

See Circular dependencies.

"Corvis cannot export a provider/module that is not a part of the currently processed module"

A module lists in exports something that is not in its providers and that none of its imports exports, or it re-exports a module it does not import. Add it to providers or import the corresponding module.

"The provider X was found but it is not of the requested type Y"

The token exists, but the registered value is of another type. This happens with string tokens: for example, Provider::use_value("PORT", 3000) registers an i32, and a field #[inject("PORT")] port: Arc<u16> asks for a u16. Use the same type on both sides (Provider::use_value("PORT", 3000u16)).

"Error while instantiating X: ..."

A factory (Provider::use_factory, register_async, for_root_async) returned an error. The message includes the cause. A typical case is a required environment variable that is missing, such as JWT_SECRET in examples/tertulia.

Attribute compile errors

Message	Cause
#[get] must be used on a method inside a #[routes] impl block	The controller's impl does not carry #[routes]
#[use_guards] must be placed below #[controller] or on a method inside #[routes]	Class attributes go below #[controller] (Rust processes attributes in order)
request-scoped providers are not supported; use transient or default scope	#[injectable(scope = "request")] does not exist. See Injection scopes
unknown #[module] key; expected imports, controllers, providers, exports or global	A misspelled key in #[module(...)]
#[corvis::main] requires an async fn	async is missing on main

A field of an #[injectable] that is not Arc<T>, Option<Arc<T>> or ModuleRef is initialized with Default. If its type does not implement Default, the compiler error mentions it: initialize it with #[init(expr)].

The port is busy

ERROR [CorvisApplication] listen EADDRINUSE / bind error on 0.0.0.0:3000: ...

Another process (often a previous run of the same application) is listening on that port. Stop it or use another port.

404 Cannot GET /route

{ "message": "Cannot GET /cats", "error": "Not Found", "statusCode": 404 }

• Check the global prefix (set_global_prefix("api") moves everything to /api/...) and URI versioning (/api/v1/...). The Mapped {...} logs at startup show the actual routes.
• Check that the controller is in the controllers of a module reachable from the root module.
• With header or media type versioning, a request without a version only reaches routes without a version or VERSION_NEUTRAL. See Versioning.

413, 415 and 400 from the body parser

Response	Cause
413 request entity too large	The JSON or urlencoded body exceeds 100 kb. Raise it with app.use_body_parser("json", bytes)
415 unsupported content encoding	The body is compressed (gzip, br...): it is not supported
415 unsupported charset "..."	A charset other than UTF-8 (or latin1 in urlencoded)
400 with a JSON.parse message	Malformed JSON, or nested more than 256 levels deep

The handler receives null in #[body]

The body was not parsed because the Content-Type is neither application/json nor application/x-www-form-urlencoded. Check the client's header, or read the bytes with req.raw_body() (see Raw body).