MTConnectTagDefinitionFactory.TryFromTagConfig resolves the coercion type as
FirstNonBlank(blob.DriverDataType, blob.DataType) — driverDataType OUT-RANKS
dataType — while MTConnectTagConfigModel read and wrote dataType alone. That
broke in both directions at once:
* a blob carrying "driverDataType": "Strng" was accepted at authoring while
the runtime rejected the tag (the residual slice of #549), and
* a VALID driverDataType silently overrode whatever type the editor displayed
and saved, so the editor showed a lie and a save RETYPED the tag.
Both halves land together, mirroring the existing IdKeys pattern:
* FromJson reads DataTypeKeys = [driverDataType, dataType] in the runtime's
precedence, with the runtime's own per-key semantics — absent/JSON-null and
present-but-blank fall through, a non-string token stops the walk (the
runtime deserialise throws JsonException on it and rejects the whole tag),
and the raw TOKEN is captured so Validate() judges what the driver judges.
* ToJson drops every non-canonical DataTypeKeys entry and writes dataType as
the enum NAME, so the alias can never out-rank the key the editor writes on
the next load.
* Validate() now names the offending spelling rather than always saying
"dataType".
Doing only one half silently retypes existing tags on their next save; the
falsification runs recorded in the PR confirm each half-fix reddens a distinct
test.
Joseph Doherty
8971861b7c