Support double _has expressions (#1939)

* Support nested _has queries

* Add changelog

hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/5_1_0/1939-double-has-expressions.yaml

@@ -0,0 +1,5 @@
+---
+type: add
+issue: 1939
+title: "The JPA server is now able to support _has queries where the linked search expression on the right hand side of the
+   _has parameter is a second _has query."

hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/dao/predicate/PredicateBuilderReference.java

@@ -62,6 +62,7 @@ import ca.uhn.fhir.rest.api.server.RequestDetails;
 import ca.uhn.fhir.rest.api.server.storage.ResourcePersistentId;
 import ca.uhn.fhir.rest.param.CompositeParam;
 import ca.uhn.fhir.rest.param.DateParam;
+import ca.uhn.fhir.rest.param.HasOrListParam;
 import ca.uhn.fhir.rest.param.HasParam;
 import ca.uhn.fhir.rest.param.NumberParam;
 import ca.uhn.fhir.rest.param.ParameterUtil;
@@ -944,30 +945,46 @@ class PredicateBuilderReference extends BasePredicateBuilder {
 				throw new InvalidRequestException("Invalid resource type: " + targetResourceType);
 			}
 
-			//Ensure that the name of the search param
-			// (e.g. the `code` in Patient?_has:Observation:subject:code=sys|val)
-			// exists on the target resource type.
-			RuntimeSearchParam owningParameterDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramName);
-			if (owningParameterDef == null) {
-				throw new InvalidRequestException("Unknown parameter name: " + targetResourceType + ':' + parameterName);
-			}
-
-			//Ensure that the name of the back-referenced search param on the target (e.g. the `subject` in Patient?_has:Observation:subject:code=sys|val)
-			//exists on the target resource.
-			owningParameterDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramReference);
-			if (owningParameterDef == null) {
-				throw new InvalidRequestException("Unknown parameter name: " + targetResourceType + ':' + paramReference);
-			}
-
-			RuntimeSearchParam paramDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramName);
-
-			IQueryParameterAnd<IQueryParameterOr<IQueryParameterType>> parsedParam = (IQueryParameterAnd<IQueryParameterOr<IQueryParameterType>>) ParameterUtil.parseQueryParams(myContext, paramDef, paramName, parameters);
-
 			ArrayList<IQueryParameterType> orValues = Lists.newArrayList();
 
-			for (IQueryParameterOr<IQueryParameterType> next : parsedParam.getValuesAsQueryTokens()) {
+			if (paramName.startsWith("_has:")) {
-				orValues.addAll(next.getValuesAsQueryTokens());
+
+				ourLog.trace("Handing double _has query: {}", paramName);
+
+				String qualifier = paramName.substring(4);
+				paramName = Constants.PARAM_HAS;
+				for (IQueryParameterType next : nextOrList) {
+					HasParam nextHasParam = new HasParam();
+					nextHasParam.setValueAsQueryToken(myContext, Constants.PARAM_HAS, qualifier, next.getValueAsQueryToken(myContext));
+					orValues.add(nextHasParam);
+				}
+
+			} else {
+
+				//Ensure that the name of the search param
+				// (e.g. the `code` in Patient?_has:Observation:subject:code=sys|val)
+				// exists on the target resource type.
+				RuntimeSearchParam owningParameterDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramName);
+				if (owningParameterDef == null) {
+					throw new InvalidRequestException("Unknown parameter name: " + targetResourceType + ':' + parameterName);
+				}
+
+				//Ensure that the name of the back-referenced search param on the target (e.g. the `subject` in Patient?_has:Observation:subject:code=sys|val)
+				//exists on the target resource.
+				owningParameterDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramReference);
+				if (owningParameterDef == null) {
+					throw new InvalidRequestException("Unknown parameter name: " + targetResourceType + ':' + paramReference);
+				}
+
+				RuntimeSearchParam paramDef = mySearchParamRegistry.getSearchParamByName(targetResourceDefinition, paramName);
+				IQueryParameterAnd<IQueryParameterOr<IQueryParameterType>> parsedParam = (IQueryParameterAnd<IQueryParameterOr<IQueryParameterType>>) ParameterUtil.parseQueryParams(myContext, paramDef, paramName, parameters);
+
+				for (IQueryParameterOr<IQueryParameterType> next : parsedParam.getValuesAsQueryTokens()) {
+					orValues.addAll(next.getValuesAsQueryTokens());
+				}
+
 			}
+
 			//Handle internal chain inside the has.
 			if (parameterName.contains(".")) {
 				String chainedPartOfParameter = getChainedPart(parameterName);

hapi-fhir-jpaserver-base/src/test/java/ca/uhn/fhir/jpa/dao/r4/FhirResourceDaoR4SearchNoFtTest.java

@@ -876,6 +876,11 @@ public class FhirResourceDaoR4SearchNoFtTest extends BaseJpaR4Test {
 			Observation obs = new Observation();
 			obs.addIdentifier().setSystem("urn:system").setValue("NOLINK");
 			obs.setDevice(new Reference(devId));
+			IIdType obsId = myObservationDao.create(obs, mySrd).getId().toUnqualifiedVersionless();
+
+			DiagnosticReport dr = new DiagnosticReport();
+			dr.addResult().setReference(obsId.getValue());
+			dr.setStatus(DiagnosticReport.DiagnosticReportStatus.FINAL);
 			myObservationDao.create(obs, mySrd);
 		}
 
@@ -896,6 +901,51 @@ public class FhirResourceDaoR4SearchNoFtTest extends BaseJpaR4Test {
 		assertThat(toUnqualifiedVersionlessIdValues(myPatientDao.search(params)), empty());
 	}
 
+	@Test
+	public void testHasParameterDouble() {
+		// Matching
+		IIdType pid0;
+		{
+			Patient patient = new Patient();
+			patient.addIdentifier().setSystem("urn:system").setValue("00");
+			patient.addName().setFamily("Tester").addGiven("Joe");
+			pid0 = myPatientDao.create(patient, mySrd).getId().toUnqualifiedVersionless();
+
+			Observation obs = new Observation();
+			obs.addIdentifier().setSystem("urn:system").setValue("NOLINK");
+			obs.setSubject(new Reference(pid0));
+			IIdType obsId = myObservationDao.create(obs, mySrd).getId().toUnqualifiedVersionless();
+
+			DiagnosticReport dr = new DiagnosticReport();
+			dr.addResult().setReference(obsId.getValue());
+			dr.setStatus(DiagnosticReport.DiagnosticReportStatus.FINAL);
+			myDiagnosticReportDao.create(dr, mySrd);
+		}
+
+		// Matching
+		{
+			Patient patient = new Patient();
+			patient.addIdentifier().setSystem("urn:system").setValue("001");
+			patient.addName().setFamily("Tester").addGiven("Joe");
+			IIdType pid1 = myPatientDao.create(patient, mySrd).getId().toUnqualifiedVersionless();
+
+			Observation obs = new Observation();
+			obs.addIdentifier().setSystem("urn:system").setValue("NOLINK");
+			obs.setSubject(new Reference(pid1));
+			myObservationDao.create(obs, mySrd).getId().toUnqualifiedVersionless();
+
+		}
+
+		SearchParameterMap params = SearchParameterMap.newSynchronous();
+
+		// Double _has
+		params = new SearchParameterMap();
+		params.add("_has", new HasParam("Observation", "subject", "_has:DiagnosticReport:result:status", "final"));
+		assertThat(toUnqualifiedVersionlessIdValues(myPatientDao.search(params)), containsInAnyOrder(pid0.getValue()));
+
+	}
+
+
 	@Test
 	public void testHasParameterChained() {
 		IIdType pid0;