Symptom

No test coverage verified the end-to-end Phase 3 source-wiring invariants as a suite: that every representative targeting node type (Pin, DataPoint, Button, TaskList, Trigger, Cron) flows through TargetingWiringEditor; that pre-Phase3 wired nodes retain their sources/executionSource/nodeAction values through withParentSourceDefault and JSON round-trips; that PARENT_EXECUTE_SUCCESS is absent from the rendered Invoked-By options while the enum constant survives deserialization; that the multi-host source picker groups by host and deduplicates correctly; and that deleting a source node leaves source-wired subscribers structurally intact.

Root cause

Stages 1–4 (PRs #294–#297) shipped the implementation and partial test coverage in dedicated issue branches. No single closing stage verified all invariants together:

• Stage 1 (#289 / PR #294): InvokedByOptionsTest — filter + deserialization safety.
• Stage 2 (#290 / PR #295): SourcePickerLogicTest — type-first host-grouped picker logic.
• Stage 3 (#291 / PR #296): edit-rollout; no new tests (code change proven by review).
• Stage 4 (#292 / PR #297): SourceDeleteSemanticsTest — D8 non-destructive delete.
• Stage 5 (#293 / this PR): coverage for representative types, wiring round-trips, JSON safety.

The TargetingWiringContractTest in composeApp/desktopTest/ closes the remaining gaps: representative-type interface check, copy-round-trip, D4 targets-field retention, and pre-Phase3 wiring preservation (both via withParentSourceDefault and fastJson).

Fix

• Added TargetingWiringContractTest in composeApp/src/desktopTest/kotlin/krill/zone/app/ covering tasks 5.1 and 5.3 of openspec/changes/universal-source-wiring-ux/tasks.md:
  • All six representative MetaData types assert is TargetingNodeMetaData.
  • sources, executionSource, nodeAction survive copy() for each type.
  • D4: targets is retained in the data model across all six types (Phase 4 will delete it).
  • withParentSourceDefault preserves pre-configured executionSource and nodeAction; does not duplicate sources; adds the new parent when sources were empty.
  • fastJson round-trip for Pin, DataPoint, and TaskList nodes with existing wiring.
• The four previously-shipped tests (InvokedByOptionsTest, SourcePickerLogicTest, SourceDeleteSemanticsTest, NodeMetaDataSourceWiringTest) remain on main from PRs #294–#297.

Prevention

• D4 (conscious): targets is hidden from the editor UI but preserved in all MetaData types and processors until Phase 4 reworks the 8 targets-reading processors. Any new editor must NOT expose a targets picker. The TargetingWiringContractTest guards this by asserting (meta as TargetingNodeMetaData).targets is readable and non-empty when set.
• D7 (conscious, pre-release): Calculation formula-variable node refs and LogicGate input-type enforcement are deferred. These must be addressed before the first public release. Do not merge a Calculation or LogicGate edit that re-adds the formula-variable-as-source keypad buttons until the formula builder is ready.
• When adding a new targeting node type: add it to TargetingWiringContractTest’s representative-type assertions so interface compliance and wiring round-trips are gated from day one.
• JSON round-trip tests are cheap and catch serializer-registration misses early — prefer them over “it compiled” for new MetaData types.