API Go active http-service

Go HTTP handlers stop after writing a terminal error response

api-go-003

Intent

A handler that continues after http.Error can write conflicting output or perform side effects after the request has already failed.

Applicability

Applies when the diff changes Go net/http handlers or wrappers that write terminal error responses.

What to inspect

Calls to http.Error, other terminal response writers, early returns, and any work performed after the error path.

Pass criteria

The handler returns immediately after writing a terminal error response.

Fail criteria

The handler writes an error and then continues executing business logic or attempts to write another response body or status.

Do not flag

Non-terminal logging or metric helpers that do not write the response, or helper functions that clearly return control to the caller before more work happens.

Confidence guidance

HIGH when http.Error is followed by more handler work. MEDIUM when a helper may already return. LOW when the response-writing path is indirect.

Remediation

Return immediately after a terminal error response.

Pass example

if err != nil {
    http.Error(w, "bad request", http.StatusBadRequest)
    return
}

Fail example

if err != nil {
    http.Error(w, "bad request", http.StatusBadRequest)
}
processRequest()