When a Code without system is passed in to in, check only the code value and throw if the resolved value set contains codes from multiple code systems (#1026)

For `Code`s without system passed in to `in`, check only the code value and throw if the resolved value set contains codes from multiple code systems

Author: antvaset

cqf-fhir-cql/src/main/java/org/opencds/cqf/fhir/cql/engine/terminology/RepositoryTerminologyProvider.java

@@ -97,12 +97,22 @@ public boolean in(Code code, ValueSetInfo valueSet) {
 
         List<Code> codes = this.expand(valueSet);
 
+        if (code.getSystem() == null) {
+            // If the system is not provided and the resolved value set contains codes from multiple code systems, a
+            // run-time error is thrown because the operation is ambiguous
+            var distinctSystems = codes.stream().map(Code::getSystem).distinct().count();
+            if (distinctSystems > 1) {
+                throw new IllegalArgumentException(
+                        "The 'in' operation is ambiguous because the the code system is not provided and the resolved value set contains codes from multiple code systems");
+            }
+        }
+
         // This range includes all codes that have an equivalent code value,
         // So we only need to check the code system.
         Range range = this.getSearchRange(code, codes);
         for (int i = range.start; i < range.end; i++) {
             var c = codes.get(i);
-            if (c.getSystem().equals(code.getSystem())) {
+            if (code.getSystem() == null || c.getSystem().equals(code.getSystem())) {
                 return true;
             }
         }

cqf-fhir-cql/src/test/java/org/opencds/cqf/fhir/cql/engine/terminology/RepositoryTerminologyProviderTest.java

@@ -1,6 +1,7 @@
 package org.opencds.cqf.fhir.cql.engine.terminology;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.isNull;
@@ -24,6 +25,7 @@ class RepositoryTerminologyProviderTest {
     private static final String VALID_VALUE_SET_URL = "http://example.com/ValueSet/ValidValueSet";
     private static final String MISSING_SYSTEM_VALUE_SET_URL = "http://example.com/ValueSet/MissingSystemValueSet";
     private static final String MISSING_CODE_VALUE_SET_URL = "http://example.com/ValueSet/MissingCodeValueSet";
+    private static final String MULTIPLE_SYSTEMS_VALUE_SET_URL = "http://example.com/ValueSet/MultipleSystemsValueSet";
 
     @Test
     void validCodesInValueSet() {
@@ -37,6 +39,15 @@ void validCodesInValueSet() {
         assertFalse(terminologyProvider.in(codeDoesNotExistInValueSet, vsInfo));
     }
 
+    @Test
+    void failOnCodeWithoutSystemAndMultiSystemValueSet() {
+        var terminologyProvider = terminologyProviderWith("MultipleSystemsValueSet");
+        var vsInfo = new ValueSetInfo().withId(MULTIPLE_SYSTEMS_VALUE_SET_URL);
+
+        var code = new Code().withCode("123");
+        assertThrows(IllegalArgumentException.class, () -> terminologyProvider.in(code, vsInfo));
+    }
+
     @Test
     void missingCodeValueSetMatches() {
         var terminologyProvider = terminologyProviderWith("MissingCodeValueSet");
@@ -49,7 +60,7 @@ void missingCodeValueSetMatches() {
         assertFalse(terminologyProvider.in(codeMissingCode, vsInfo));
 
         var codeMissingSystem = new Code().withCode("123");
-        assertFalse(terminologyProvider.in(codeMissingSystem, vsInfo));
+        assertTrue(terminologyProvider.in(codeMissingSystem, vsInfo));
     }
 
     @Test
@@ -64,7 +75,7 @@ void missingSystemValueSetMatches() {
         assertFalse(terminologyProvider.in(codeMissingCode, vsInfo));
 
         var codeMissingSystem = new Code().withCode("123");
-        assertFalse(terminologyProvider.in(codeMissingSystem, vsInfo));
+        assertTrue(terminologyProvider.in(codeMissingSystem, vsInfo));
     }
 
     IRepository mockRepositoryFor(String id) {

cqf-fhir-cql/src/test/resources/org/opencds/cqf/fhir/cql/engine/terminology/MultipleSystemsValueSet.json

@@ -0,0 +1,21 @@
+{
+  "resourceType": "ValueSet",
+  "id": "MultipleSystemsValueSet",
+  "url": "http://example.com/ValueSet/MultipleSystemsValueSet",
+  "expansion": {
+    "contains": [
+      {
+        "system": "http://example.com/CodeSystem/Codes1",
+        "code": "123"
+      },
+      {
+        "system": "http://example.com/CodeSystem/Codes2",
+        "code": "456"
+      },
+      {
+        "system": "http://example.com/CodeSystem/Codes3",
+        "code": "789"
+      }
+    ]
+  }
+}