Part #120, reject unmatched derived command dispatch

[sylvesterkaczmarek]

Part #120.

Description

Distinguish non-derived message types from failed derivative identification. Query the type metadata first, retain position-zero dispatch only for types without derivatives, and reject failed identification before any handler is invoked. Preserve matching-derivative routing and message-size validation, and propagate an unreadable message size instead of using it.

This proposes CFE_STATUS_VALIDATION_FAILURE for unmatched derived commands. Please confirm the intended dispatch/error semantics before merging; #120 remains open as a clarification issue.

Testing performed

Debian 12 arm64, GCC 12.2, EDS-enabled native cFE/OSAL build:

• Built the production edsmsg library and the new edsmsg-dispatcher-test target.
• All five targeted CTest targets passed: Config, ES, SB, TBL, and the dispatcher.
• Eight new dispatcher test groups, 50 assertions, exercise matching handlers, non-derived fallback, rejected identification, metadata/size errors, and wrong message lengths. The regressions fail on the unmodified dispatcher.
• A supplementary local check with actual generated CFE_ES command types and the real EdsLib runtime passed 27 assertions, including unknown function-code rejection and non-derived SendHk handling.
• Both dispatcher and generated-data checks passed 100 runs under AddressSanitizer and UndefinedBehaviorSanitizer during initial validation, and were rebuilt and passed again before submission.
• Clang-format 19, compiler warnings as errors, and git diff --check passed.

The committed test target runs within an EDS-enabled cFE build. Full standalone EdsLib validation, COSMOS, mission/network integration, and hardware testing were not run. The generated-data check was a supplementary local validation, not an additional committed target.

Expected behavior changes

No public signature changes. Unmatched derived commands are rejected instead of invoking the first handler. Genuinely non-derived commands retain handler zero. Invalid database metadata returns CFE_SB_INTERNAL_ERR.

Contributor info

Sylvester Kaczmarek, Personal. No third-party code added. Contributor License Agreement submission status is unverified.