v7.8.2

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 (PR #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.