karatelabs/karate · error · RuntimeException

configure requires '=' assignment:

Error message

configure requires '=' assignment: 

What it means

The `configure` keyword requires the form `configure key = expression`; the step text must contain an '=' assignment operator for StepUtils.findAssignmentOperator to split the key from the value expression. When no '=' is present the executor cannot determine what to configure and throws with the full step text.

Solutions

1. Add the '=' assignment: `configure headers = { Authorization: 'Bearer x' }`
2. If the value is large, keep '=' with an empty expression and supply a docstring
3. Replace with JS form: `karate.configure('key', value)` inside an eval step
4. Check for typos that swallowed the '=' character

Example fix

// before
* configure ssl true
// after
* configure ssl = true

// step text check in custom runner
if (!stepText.contains("=")) throw new IllegalArgumentException("configure requires '=' assignment");

When it happens

Trigger: Writing `configure headers` without `= value`; using `:` or other separators instead of `=`; configure with only a docstring but no `=` in the text (the docstring fallback only applies AFTER the '=' split succeeds).

Common situations: Typos like `configure retry count 5`; pasting config from JSON-style syntax; translating `karate.configure('x', y)` JS calls into keyword form incorrectly.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• assignment to constant
• assignment to constant
• cannot set . (on )
• cannot set on
• cannot write to optional call expression

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/214045845bccc3d1. Report an issue: GitHub.

Appendix: source

Thrown at karate-core/src/main/java/io/karatelabs/core/StepExecutor.java:3007

            html = runtime.getKarate().doc(Map.of("read", path));
        } else if (value instanceof Map) {
            html = runtime.getKarate().doc((Map<String, Object>) value);
        } else {
            throw new RuntimeException("doc requires a string path or map with 'read' key, got: " + value);
        }
        // Embed the rendered HTML in the step result for reports
        if (html != null && !html.isEmpty()) {
            LogContext.get().embed(html.getBytes(java.nio.charset.StandardCharsets.UTF_8), "text/html");
        }
    }

    // ========== Config ==========

    private void executeConfigure(Step step) {
        String text = step.getText();
        int eqIndex = StepUtils.findAssignmentOperator(text);
        if (eqIndex < 0) {
            throw new RuntimeException("configure requires '=' assignment: " + text);
        }
        String key = text.substring(0, eqIndex).trim();
        String expr = text.substring(eqIndex + 1).trim();
        if (expr.isEmpty() && step.getDocString() != null) {
            expr = step.getDocString();
        }
        Object value;
        if (key.equals("javaBridgeEnabled")) {
            // Toggle Java interop (Java.type) for this engine. Mocks disable it by default
            // so untrusted request data evaluated as embedded expressions cannot reach Java
            // class loading; a trusted feature opts back in with `configure javaBridgeEnabled = true`.
            Object enabled = evalKarateExpression(expr);
            runtime.getKarate().setJavaBridgeEnabled(Boolean.parseBoolean(String.valueOf(enabled)));
            return;
        }
        if (key.equals("requestExpressionsEnabled")) {
            // Opt a mock back in to evaluating embedded expressions in request-derived data
            // (off by default). Re-opens the injection surface - only for trusted mocks.

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