5014 only positive ints (#5050)

* limit ints, add test and changelog

* changelog

hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/6_8_0/5014-negative-partitions-not-allowed.yaml

@@ -0,0 +1,4 @@
+---
+type: add
+issue: 5014
+title: "There was a bug with automatic partition ID selection where it was not bound to positive integers and could return a value that was out of range. This has been fixed."

hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/partition/PartitionLookupSvcImpl.java

@@ -123,14 +123,14 @@ public class PartitionLookupSvcImpl implements IPartitionLookupSvc {
 	}
 
 	/**
-	 * Generate a random int which is guaranteed to  be unused by an existing partition.
+	 * Generate a random postive integer between 1 and Integer.MAX_VALUE, which is guaranteed to  be unused by an existing partition.
 	 * @return an integer representing a partition ID that is not currently in use by the system.
 	 */
 	public int generateRandomUnusedPartitionId() {
-		int candidate = ThreadLocalRandom.current().nextInt();
+		int candidate = ThreadLocalRandom.current().nextInt(1, Integer.MAX_VALUE);
 		Optional<PartitionEntity> partition = myPartitionDao.findById(candidate);
 		while (partition.isPresent()) {
-			candidate = ThreadLocalRandom.current().nextInt();
+			candidate = ThreadLocalRandom.current().nextInt(1, Integer.MAX_VALUE);
 			partition = myPartitionDao.findById(candidate);
 		}
 		return candidate;

hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/partition/PartitionLookupSvcImplTest.java

@@ -0,0 +1,55 @@
+package ca.uhn.fhir.jpa.partition;
+
+import ca.uhn.fhir.context.FhirContext;
+import ca.uhn.fhir.interceptor.api.IInterceptorService;
+import ca.uhn.fhir.jpa.cache.ResourceChangeListenerRegistryInterceptor;
+import ca.uhn.fhir.jpa.dao.data.IPartitionDao;
+import ca.uhn.fhir.jpa.model.config.PartitionSettings;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.transaction.PlatformTransactionManager;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(SpringExtension.class)
+class PartitionLookupSvcImplTest {
+
+	@Autowired
+	private PartitionLookupSvcImpl myPartitionLookupSvc;
+	@MockBean
+	PartitionSettings myPartitionSettings;
+	@MockBean
+	IInterceptorService myInterceptorBroadcaster;
+	@MockBean
+	IPartitionDao myPartitionDao;
+	@MockBean
+	private FhirContext myFhirCtx;
+	@MockBean
+	private PlatformTransactionManager myTxManager;
+
+	@Configuration
+	static class SpringContext {
+		@Bean
+		public PartitionLookupSvcImpl partitionLookupSvcImplTest() {
+			return new PartitionLookupSvcImpl();
+		}
+	}
+	@Test
+	void generateRandomUnusedPartitionId() {
+		when(myPartitionDao.findById(any())).thenReturn(Optional.empty());
+		for (int i = 0; i<10000; i++) {
+			int randomUnusedPartitionId = myPartitionLookupSvc.generateRandomUnusedPartitionId();
+			assertTrue(randomUnusedPartitionId >= 1);
+		}
+	}
+}