Remove ExplainError.

It was a duplicate of `QueryError`.

Arguably, the explain endpoints could have always returned `QueryError`
or `MutationError` instead.

crates/sdk/src/connector.rs

@@ -78,7 +78,7 @@ pub trait Connector {
     /// This function implements the [query/explain endpoint](https://hasura.github.io/ndc-spec/specification/explain.html)
     /// from the NDC specification.
     ///
-    /// The [`ExplainError`] type is provided as a convenience to connector authors, to be used on
+    /// The [`QueryError`] type is provided as a convenience to connector authors, to be used on
     /// error.
     async fn query_explain(
         configuration: &Self::Configuration,
@@ -91,7 +91,7 @@ pub trait Connector {
     /// This function implements the [mutation/explain endpoint](https://hasura.github.io/ndc-spec/specification/explain.html)
     /// from the NDC specification.
     ///
-    /// The [`ExplainError`] type is provided as a convenience to connector authors, to be used on
+    /// The [`MutationError`] type is provided as a convenience to connector authors, to be used on
     /// error.
     async fn mutation_explain(
         configuration: &Self::Configuration,

crates/sdk/src/connector/error.rs

@@ -280,82 +280,6 @@ impl From<QueryError> for ErrorResponse {
     }
 }
 
-/// Errors which occur when explaining a query.
-///
-/// See [`Connector::query_explain`, `Connector::mutation_explain`].
-#[derive(Debug, thiserror::Error)]
-pub enum ExplainError {
-    /// The request was invalid or did not match the
-    /// requirements of the specification. This indicates
-    /// an error with the client.
-    #[error("invalid request: {}", .0.message)]
-    InvalidRequest(models::ErrorResponse),
-    /// The request was well formed but was unable to be
-    /// followed due to semantic errors. This indicates
-    /// an error with the client.
-    #[error("unprocessable content: {}", .0.message)]
-    UnprocessableContent(models::ErrorResponse),
-    /// The request relies on an unsupported feature or
-    /// capability. This may indicate an error with the client,
-    /// or just an unimplemented feature.
-    #[error("unsupported operation: {}", .0.message)]
-    UnsupportedOperation(models::ErrorResponse),
-}
-
-impl ExplainError {
-    pub fn new_invalid_request<T: ToString>(message: &T) -> Self {
-        Self::InvalidRequest(models::ErrorResponse {
-            message: message.to_string(),
-            details: serde_json::Value::Null,
-        })
-    }
-
-    pub fn new_unprocessable_content<T: ToString>(message: &T) -> Self {
-        Self::UnprocessableContent(models::ErrorResponse {
-            message: message.to_string(),
-            details: serde_json::Value::Null,
-        })
-    }
-
-    pub fn new_unsupported_operation<T: ToString>(message: &T) -> Self {
-        Self::UnsupportedOperation(models::ErrorResponse {
-            message: message.to_string(),
-            details: serde_json::Value::Null,
-        })
-    }
-
-    #[must_use]
-    pub fn with_details(self, details: serde_json::Value) -> Self {
-        match self {
-            Self::InvalidRequest(models::ErrorResponse { message, .. }) => {
-                Self::InvalidRequest(models::ErrorResponse { message, details })
-            }
-            Self::UnprocessableContent(models::ErrorResponse { message, .. }) => {
-                Self::UnprocessableContent(models::ErrorResponse { message, details })
-            }
-            Self::UnsupportedOperation(models::ErrorResponse { message, .. }) => {
-                Self::UnsupportedOperation(models::ErrorResponse { message, details })
-            }
-        }
-    }
-}
-
-impl From<ExplainError> for ErrorResponse {
-    fn from(value: ExplainError) -> Self {
-        match value {
-            ExplainError::InvalidRequest(err) => {
-                ErrorResponse::from(err).with_status_code(StatusCode::BAD_REQUEST)
-            }
-            ExplainError::UnprocessableContent(err) => {
-                ErrorResponse::from(err).with_status_code(StatusCode::UNPROCESSABLE_ENTITY)
-            }
-            ExplainError::UnsupportedOperation(err) => {
-                ErrorResponse::from(err).with_status_code(StatusCode::NOT_IMPLEMENTED)
-            }
-        }
-    }
-}
-
 /// Errors which occur when executing a mutation.
 ///
 /// See [`Connector::mutation`].