CAMEL-24136: Fix FT circuit breaker exchange properties, bulkhead, dead option, docs

[davsclaus]

Summary

Fixes medium-severity findings from a review of the Circuit Breaker EIP in camel-microprofile-fault-tolerance (CAMEL-24136).

• M1+M2 — Exchange property contract: RESPONSE_TIMED_OUT is now set in all timeout paths (with and without fallback). Guard exceptions (timeout, CB open) are now stored on the exchange before fallback invocation so the fallback can see them via EXCEPTION_CAUGHT. Removed ~20 lines of unreachable dead code from CircuitBreakerFallbackTask.
• Bulkhead enablement bug: FaultToleranceReifier.configureBulkhead() never called setBulkheadEnabled(true) on the target config, so the bulkhead was never actually wired onto the TypedGuard. Fixed.
• M4 — Dead timeoutPoolSize option: Deprecated across model, configuration, DSL, and JMX with @Deprecated(since = "4.22.0"). The option has been inert since the CAMEL-21857 TypedGuard migration.
• M3 (partial) — Misleading JMX description: getFailureRate() description now says "configured failure ratio threshold" instead of "current failure rate in percentage" (it returns the static config value, not live metrics). Documented the FT dev console metrics limitation vs resilience4j (SmallRye API does not expose per-breaker counters).
• M6 — Documentation errors: Fixed incorrect timeout default claim in circuitBreaker-eip.adoc, wrong option names in resilience4j-eip.adoc and fault-tolerance-eip.adoc, incorrect no-fallback exception behavior description, and a misordered YAML example.
• Tests: 2 new tests covering RESPONSE_TIMED_OUT and EXCEPTION_CAUGHT visibility in both no-fallback and with-fallback timeout scenarios. All 22 module tests pass.

Test plan

• mvn verify passes in camel-microprofile-fault-tolerance (22 tests, 0 failures)
• CI green on all platforms
• Verify existing circuit breaker tests in camel-resilience4j are unaffected

Claude Code on behalf of davsclaus

🤖 Generated with Claude Code

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

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[gnodet]

APPROVE — Thorough cleanup of the Fault Tolerance circuit breaker implementation. Each fix is well-targeted and addresses a real issue.

Fixes reviewed:

1. Bulkhead enablement bug (FaultToleranceReifier.java): configureBulkhead() was setting maxConcurrentCalls and waitingTaskQueue but never calling setBulkheadEnabled(true) on the target config. The bulkhead was therefore never actually wired onto the TypedGuard. Bug introduced in CAMEL-21857 (TypedGuard migration). One-line fix, high impact.

2. Timeout exchange properties (FaultToleranceProcessor.java): The old code tried to set RESPONSE_TIMED_OUT and other properties inside CircuitBreakerFallbackTask.call(), but that code was guarded by if (fallbackProcessor == null) — unreachable since the task is only instantiated when a fallback exists. The new code correctly handles timeout-without-fallback in a dedicated catch (TimeoutException e) block at the process() level, and stores the guard exception on the exchange before invoking the fallback so it's visible via EXCEPTION_CAUGHT. Dead code cleanup is clean — ~20 lines removed with equivalent behavior preserved in the right location.

3. timeoutPoolSize deprecation: Properly deprecated across model (FaultToleranceConfigurationCommon, FaultToleranceConfigurationDefinition), runtime config (FaultToleranceConfiguration), JMX (FaultToleranceProcessor), and generated metadata. All use @Deprecated(since = "4.22.0") with clear deprecation notes referencing CAMEL-21857.

4. JMX getNumberOfSlowSuccessfulCalls() bug (ResilienceProcessor.java): Was calling getNumberOfSlowCalls() instead of getNumberOfSlowSuccessfulCalls() — obvious copy-paste error. Good catch.

5. ResilienceConsole display fix: fr > 0 → fr >= 0 is correct (0% failure rate should display the full stats line); the else branch now properly uses the fc variable instead of hardcoding failure: 0.

6. JMX description fix: getFailureRate() description updated from "current failure rate in percentage" to "configured failure ratio threshold (0.0-1.0)" — it returns the static config value, not live metrics.

7. Documentation: Fixed incorrect default timeout claim, corrected option names (resilience4jConfiguration, configuration), fixed YAML example ordering (steps must come before onFallback), and clarified no-fallback/open-circuit behavior including the throwExceptionWhenHalfOpenOrOpenState option.

8. Tests: Two new focused tests covering the exact scenarios fixed — timeout without fallback (verifying all 4 exchange properties + exception type) and timeout with fallback (verifying EXCEPTION_CAUGHT visibility to the fallback processor and RESPONSE_TIMED_OUT on the result exchange). Both use the standard CamelTestSupport pattern.

Checklist:

• Tests included (2 new targeted tests)
• Generated metadata regenerated
• No public API breakage (deprecation, not removal)
• Documentation updated (3 EIP docs + generated metadata)
• Commit convention followed
• CI: pending

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Reviewed with Claude Code on behalf of gnodet. This review was generated by an AI agent and may contain inaccuracies; please verify all suggestions before applying.