language_models: Add OpenRouterError and map OpenRouter errors to LanguageModelCompletionError (#34227)

Improves the error handling for openrouter and adds automatic retry like
anthropic for few of the status codes.
Release Notes:

- Improves error messages for Openrouter provider
- Automatic retry when rate limited or Server error from Openrouter

crates/language_model/src/language_model.rs

@@ -17,6 +17,7 @@ use futures::{StreamExt, future::BoxFuture, stream::BoxStream};
 use gpui::{AnyView, App, AsyncApp, SharedString, Task, Window};
 use http_client::{StatusCode, http};
 use icons::IconName;
+use open_router::OpenRouterError;
 use parking_lot::Mutex;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize, de::DeserializeOwned};
@@ -347,6 +348,72 @@ impl From<anthropic::ApiError> for LanguageModelCompletionError {
     }
 }
 
+impl From<OpenRouterError> for LanguageModelCompletionError {
+    fn from(error: OpenRouterError) -> Self {
+        let provider = LanguageModelProviderName::new("OpenRouter");
+        match error {
+            OpenRouterError::SerializeRequest(error) => Self::SerializeRequest { provider, error },
+            OpenRouterError::BuildRequestBody(error) => Self::BuildRequestBody { provider, error },
+            OpenRouterError::HttpSend(error) => Self::HttpSend { provider, error },
+            OpenRouterError::DeserializeResponse(error) => {
+                Self::DeserializeResponse { provider, error }
+            }
+            OpenRouterError::ReadResponse(error) => Self::ApiReadResponseError { provider, error },
+            OpenRouterError::RateLimit { retry_after } => Self::RateLimitExceeded {
+                provider,
+                retry_after: Some(retry_after),
+            },
+            OpenRouterError::ServerOverloaded { retry_after } => Self::ServerOverloaded {
+                provider,
+                retry_after,
+            },
+            OpenRouterError::ApiError(api_error) => api_error.into(),
+        }
+    }
+}
+
+impl From<open_router::ApiError> for LanguageModelCompletionError {
+    fn from(error: open_router::ApiError) -> Self {
+        use open_router::ApiErrorCode::*;
+        let provider = LanguageModelProviderName::new("OpenRouter");
+        match error.code {
+            InvalidRequestError => Self::BadRequestFormat {
+                provider,
+                message: error.message,
+            },
+            AuthenticationError => Self::AuthenticationError {
+                provider,
+                message: error.message,
+            },
+            PaymentRequiredError => Self::AuthenticationError {
+                provider,
+                message: format!("Payment required: {}", error.message),
+            },
+            PermissionError => Self::PermissionError {
+                provider,
+                message: error.message,
+            },
+            RequestTimedOut => Self::HttpResponseError {
+                provider,
+                status_code: StatusCode::REQUEST_TIMEOUT,
+                message: error.message,
+            },
+            RateLimitError => Self::RateLimitExceeded {
+                provider,
+                retry_after: None,
+            },
+            ApiError => Self::ApiInternalServerError {
+                provider,
+                message: error.message,
+            },
+            OverloadedError => Self::ServerOverloaded {
+                provider,
+                retry_after: None,
+            },
+        }
+    }
+}
+
 /// Indicates the format used to define the input schema for a language model tool.
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
 pub enum LanguageModelToolSchemaFormat {