Stream: hapi
Topic: Java Validator Nullpointer
Patrick Werner (Dec 31 2019 at 14:32):
When validating against an IG with profiles where derivation isn't set the validator throws some null pointers here:
https://github.com/hapifhir/org.hl7.fhir.core/blob/630ab0afcba49043ff2b145217e6735baddfaba2/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/conformance/ProfileUtilities.java#L489
As derived.getDerivation() returns null.
Patrick Werner (Dec 31 2019 at 14:39):
I think if it getDerivation() returns null just skip the following block?
Grahame Grieve (Dec 31 2019 at 19:09):
why is derivation null?
Patrick Werner (Dec 31 2019 at 19:10):
I guess because it wasn‘t populated in the StrucDef
Patrick Werner (Dec 31 2019 at 19:11):
The StructureDefinition itself, which i parsed, does not have have it
Patrick Werner (Dec 31 2019 at 19:12):
So it ends up as Null in the Instance
Patrick Werner (Dec 31 2019 at 19:12):
Added a PR to fix it
Grahame Grieve (Dec 31 2019 at 19:17):
fix it how? how can you generate a snapshot if there's no derivation?
Patrick Werner (Jan 09 2020 at 11:07):
Sorry for the insufficient explanation last time, was on the mobile phone.
This is used in the Validator at several places: (derived.getDerivation().equals(TypeDerivationRule.SPECIALIZATION))
When you are validating against a profile which StrucDef doesn't has derivation populated a NullPointer is thrown as there is no null check and the variable derived stays null after parsing the profile.
Grahame Grieve (Jan 09 2020 at 21:37):
but why is there no derivation, and how can the SD make sense?
Patrick Werner (Jan 10 2020 at 09:49):
because derivation is 0..1 and not enforced. The parser sets derivation to null if not populated and then later throws a null pointer.
Patrick Werner (Jan 10 2020 at 09:49):
So this PR is about making these methods null-safe.
Patrick Werner (Jan 10 2020 at 09:50):
Why are you expecting StructureDefinition.derivation to be populated when it is 0..1 ?
Grahame Grieve (Jan 10 2020 at 09:56):
the only case when it shouldn't have a value is when there's no base definition. If there's a base definition, how can it be meaningful if there derivation is unknown?
Patrick Werner (Jan 10 2020 at 10:31):
i agree on a logic level, but as far as i can see a StructureDefinition with no derivation is a valid on a technical level as i can't see anything enforcing the population of the derivation. e.g.: https://simplifier.net/BasisprofilDE/organization-de-basis-0.2/~xml doesn't have it populated.
Grahame Grieve (Jan 10 2020 at 10:35):
it's valid on a technical level, but not meaningful for generating a snapshot
Patrick Werner (Jan 10 2020 at 11:48):
agree. So i'll update my PR to not default to derivation=constrain - but to catch the NullPointer and Log a meaningful error?
Grahame Grieve (Jan 10 2020 at 11:54):
I just made the change here after our discussion.
Patrick Werner (Jan 10 2020 at 11:57):
:+1:
Patrick Werner (Jan 10 2020 at 13:41):
can you push the change?
Last updated: Apr 12 2022 at 19:14 UTC
