Incorrect generation of differential when using <element-name> only <datatype> or <datatype>

[vayvy]

When constraining type choice elements with "only" to specific datatypes, the slicing in the differential is open, but should be closed and constrained to the defined dataytypes.

Example

FSH
* collected[x] only dateTime or Period

Differential
{ "id": "Specimen.collection.collected[x]", "path": "Specimen.collection.collected[x]", "slicing": { "discriminator": [ { "type": "type", "path": "$this" } ], "ordered": false, "rules": "open" }

[cmoesel]

I'm not able to reproduce this as described above because Speciment.collection.collected[x] is already only dateTime or Period -- so constraining it to dateTime or Period does not produce a differential at all.

I assume you are also doing something with specific type slices, such as:

* collection
  * collected[x] only dateTime or Period
  * collectedDateTime ^short = "Date collected"

This will force the creation of a type slice and also introduce default type slicing rules to collected[x].

The slicing rules are open on purpose. Even if a choice type is constrained to a subset of types, authors are not required to create slices for each of those types. You only need to create slices for the types you want to add additional constraints (or documentation) to. If we were to set slicing to closed, then that would prevent child profiles from adding constraints to one of the allowed choices (unless the parent already explicitly created a slice for it).

Conversely, just because a choice type slicing is open, that does not mean that people can use any type they want. They're still constrained to only using the types that are specified in the profile's type array.

If an author still wants to close the slicing, they always have the option to explicitly do so using a carrot rule (e.g., * collected[x] ^slicing.rules = #closed).

[vayvy]

Thank you for the clarification. However, a question or issue still remains. The sushi and the IG publisher are apparently handling this differently.While in the differential generated by sushi the slicing is open, the snapshot generated by the IG Publisher sets the slicing to closed anyways. Should the toolings not behave the same, or am I missing something here?

Example

Differential (sushi)
{ "id" : "Observation.value[x]", "path" : "Observation.value[x]", "slicing" : { "discriminator" : [{ "type" : "type", "path" : "$this" }], "ordered" : false, "rules" : "open" }

Snapshot (IG Publisher)
{ "id" : "Observation.value[x]", "path" : "Observation.value[x]", "slicing" : { "discriminator" : [{ "type" : "type", "path" : "$this" }], "ordered" : false, "rules" : "closed" }, "short" : "Actual result", "requirements" : "An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.", "min" : 0, "max" : "1", "base" : { "path" : "Observation.value[x]", "min" : 0, "max" : "1" }, "type" : [{ "code" : "Quantity" }, { "code" : "CodeableConcept" }, { "code" : "Range" }, { "code" : "Ratio" }] }

[cmoesel]

I see what's happening. The IG Publisher is being smart: if it detects that you've already defined all possible slices, it will close the slicing for you. If you haven't defined all the slices, however, it will keep it open.

For example, the following profile will still have an open slicing after running through the IG Publisher:

Profile: MyObservationWithASlice
Parent: Observation
* value[x] only string or CodeableConcept or Quantity
* valueString ^short = "My custom short description on string slice"

But this profile will have a closed slicing after running it through the IG Publisher (because there are no other possible slices):

Profile: MyObservationWithAllSlices
Parent: Observation
* value[x] only string or CodeableConcept or Quantity
* valueString ^short = "My custom short description on string slice"
* valueCodeableConcept ^short = "My custom short description on CodeableConcept slice"
* valueQuantity ^short = "My custom short description on string slice"

If all possible slices are defined, then it's not really possible to define any other valid slices in this case. In that respect, even a slicing that's shown as open is effectively closed. So... I don't think any real harm is done by SUSHI leaving it open, but we can consider having SUSHI detect this situation and automatically close it (like the IG Publisher does).