hasura/graphql-engine · error · BuildRequestError

Failed to convert session: {0}

Error message

Failed to convert session: {0}

What it means

The engine could not convert the request's session/authorization object into the session representation sent to the pre-NDC-response plugin; the string detail says what failed. This occurs while building the outbound hook request, before any network call. It reflects an auth/session shape the conversion code does not handle.

Source

Thrown at v3/crates/plugins/pre-ndc-response-plugin/src/execute.rs:52

        error: serde_json::Value,
    },
}

#[derive(Debug, thiserror::Error)]
pub enum BuildRequestError {
    #[error("Invalid header name {header_name}: {error}")]
    InvalidHeaderName {
        header_name: String,
        #[source]
        error: InvalidHeaderName,
    },
    #[error("Invalid header value for header {header_name}: {error}")]
    InvalidHeaderValue {
        header_name: HeaderName,
        #[source]
        error: InvalidHeaderValue,
    },
    #[error("Failed to convert session: {0}")]
    SessionConversionError(String),
    #[error("Failed to convert session variable '{variable_name}': {error}")]
    SessionVariableConversionError {
        variable_name: SessionVariableName,
        error: serde_json::Error,
    },
    #[error("Serialization error: {0}")]
    SerializationError(#[from] serde_json::Error),
}

impl TraceableError for Error {
    fn visibility(&self) -> ErrorVisibility {
        match self {
            Error::BuildRequestError(_, _) => ErrorVisibility::Internal,
            Error::PluginUserError { .. }
            | Error::ReqwestError(_)
            | Error::PluginRequestParseError(_)
            | Error::ErrorWhileMakingHTTPRequestToTheHook(_, _)

View on GitHub (pinned to 724551b9ae)

Solutions

1. Read the detail string to identify the failing session field
2. Align IdP claims / auth config with the session format the plugin expects
3. Test with a minimal standard JWT to isolate the problematic claim
4. Deploy engine and plugin versions together

if let Err(Error::SessionConversionError(detail)) = res {
    tracing::error!(detail, "session conversion failed in response hook");
}

When it happens

Trigger: A request with an auth session whose claims structure cannot map to the plugin session format, raising SessionConversionError(detail) in the response-hook path.

Common situations: Changed auth mode or IdP claim layout without updating plugin config; anonymous requests hitting a hook that expects authenticated sessions; engine upgrade changing role serialization.

Related errors

• Failed to convert session: {0}
• Failed to convert session variable '{variable_name}': {error
• Failed to convert session variable '{variable_name}': {error
• Serde error: {error}
• Condition {condition_hash} not found

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/61e13c4cda8e315d. Report an issue: GitHub.