Version 7.8.2
=============

Patch release: **state-machine validation errors now reach the user** in
the Web Modeling Editor instead of being silently swallowed, and
``StateMachine.validate()`` gains its first two structural rules. No
metamodel API changes — the new rules sit behind the existing
``validate()`` entry point and a previously-empty stub is now filled
in. Closes `#467 <https://github.com/BESSER-PEARL/BESSER/issues/467>`_
(PR `#545 <https://github.com/BESSER-PEARL/BESSER/pull/545>`_, thanks
to Vasiliki Zontanou).

Fixes
-----

* **Silent error swallowing in the state-machine processor**: in
  ``besser/utilities/web_modeling_editor/backend/services/converters/json_to_buml/state_machine_processor.py``
  three ``except ValueError`` clauses called ``logger.warning(...)``
  and continued, so duplicate state names, invalid transitions, and
  guard-only-transition failures were dropped on the floor and never
  surfaced through ``/validate-diagram`` or ``/generate-output``.
  All three sites now re-raise as ``ConversionError``, matching the
  pattern already in ``class_diagram_processor.py``.
* **Project converter dropped the propagated error**: even after the
  processor was fixed, the JSON→BUML project converter at
  ``besser/utilities/web_modeling_editor/backend/services/converters/json_to_buml/project_converter.py``
  wrapped each ``StateMachineDiagram`` processing call in a
  ``try/except Exception → logger.warning`` and continued the loop —
  so the new ``ConversionError`` was caught and discarded before
  reaching the API layer. The wrapper is removed; errors now reach
  the user.

Validation rules
----------------

``StateMachine.validate()`` in
``besser/BUML/metamodel/state_machine/state_machine.py`` was a stub.
It now collects errors and warnings in the same style as
``DomainModel.validate()`` and enforces two structural rules:

* **Final state with outgoing transitions** (error): a final state
  marks the end of execution and must not have outgoing transitions;
  this violates the UML specification.
* **Unreachable non-initial state** (warning): a state that is not
  the initial state and has no incoming transitions can never be
  visited at runtime.

Construction-time constraints (duplicate state names, invalid
transition targets, missing initial state) continue to be enforced by
``StateMachine.new_state()`` and ``TransitionBuilder.go_to()`` and
raise a ``ValueError`` immediately.

Behavior change worth flagging
------------------------------

Project imports containing **one invalid state machine** previously
succeeded for the rest of the diagrams while silently dropping the
broken state machine. They now fail the import outright with the
state machine's ``ConversionError``. The error was always present in
the model — the editor just stopped surfacing it. If you relied on
"partial" project imports as a workflow, fix the state-machine
diagram in question (or remove it) before re-importing.

Tests and docs
--------------

* ``tests/BUML/metamodel/state_machine/test_state_machine.py`` gains
  ``test_validate_unreachable_states`` and
  ``test_validate_final_state_with_transitions`` to cover both rules.
* ``tests/utilities/web_modeling_editor/backend/test_api_integration.py``
  ``test_validate_state_machine_duplicate_names`` is tightened to
  assert ``isValid is False`` and that the offending state name
  reaches ``errors`` — previously it documented the silent-skip
  behavior that this release removes.
* ``docs/source/buml_language/model_types/state_machine.rst`` documents
  the new rules.