pg-keyerror-includes-missing-node-id
IN premise
When `add_node` references a nonexistent node in `sl=` or `unless=`, PgApi raises `KeyError` with the missing node ID in the exception message — tested via `pytest.raises(KeyError, match="ghost")` — enabling callers to identify which reference is dangling.
Summary
When you try to add a node that depends on a node that doesn't exist, the Postgres backend tells you exactly which missing node caused the problem by including its ID in the error. This matters because it lets callers give useful error messages or programmatically recover, rather than just getting a generic "something went wrong" failure.
Details
| Source | entries/2026/05/05/tests-test_pg.md |