Protect against NPE in isAlreadyPromoted

Fixes gh-27094

Author: philwebb

ci/images/releasescripts/src/main/java/io/spring/concourse/releasescripts/artifactory/ArtifactoryService.java

@@ -20,6 +20,7 @@
 
 import io.spring.concourse.releasescripts.ReleaseInfo;
 import io.spring.concourse.releasescripts.artifactory.payload.BuildInfoResponse;
+import io.spring.concourse.releasescripts.artifactory.payload.BuildInfoResponse.Status;
 import io.spring.concourse.releasescripts.artifactory.payload.PromotionRequest;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -96,7 +97,12 @@ private boolean isAlreadyPromoted(String buildName, String buildNumber, String t
 			logger.debug("Checking if already promoted");
 			ResponseEntity<BuildInfoResponse> entity = this.restTemplate
 					.getForEntity(BUILD_INFO_URL + buildName + "/" + buildNumber, BuildInfoResponse.class);
-			BuildInfoResponse.Status status = entity.getBody().getBuildInfo().getStatuses()[0];
+			Status[] statuses = entity.getBody().getBuildInfo().getStatuses();
+			BuildInfoResponse.Status status = (statuses != null) ? statuses[0] : null;
+			if (status == null) {
+				logger.debug("Returned no status object");
+				return false;
+			}
 			logger.debug("Returned repository " + status.getRepository() + " expecting " + targetRepo);
 			return status.getRepository().equals(targetRepo);
 		}

ci/images/releasescripts/src/test/java/io/spring/concourse/releasescripts/artifactory/ArtifactoryServiceTests.java

@@ -97,6 +97,17 @@ void promoteWhenCheckForArtifactsAlreadyPromotedFails() {
 		this.server.verify();
 	}
 
+	@Test
+	void promoteWhenCheckForArtifactsAlreadyPromotedReturnsNoStatus() {
+		this.server.expect(requestTo("https://repo.spring.io/api/build/promote/example-build/example-build-1"))
+				.andRespond(withStatus(HttpStatus.CONFLICT));
+		this.server.expect(requestTo("https://repo.spring.io/api/build/example-build/example-build-1"))
+				.andRespond(withJsonFrom("no-status-build-info-response.json"));
+		assertThatExceptionOfType(HttpClientErrorException.class)
+				.isThrownBy(() -> this.service.promote("libs-milestone-local", getReleaseInfo()));
+		this.server.verify();
+	}
+
 	@Test
 	void promoteWhenPromotionFails() {
 		this.server.expect(requestTo("https://repo.spring.io/api/build/promote/example-build/example-build-1"))

ci/images/releasescripts/src/test/resources/io/spring/concourse/releasescripts/artifactory/no-status-build-info-response.json

@@ -0,0 +1,26 @@
+{
+  "buildInfo": {
+    "version": "1.0.1",
+    "name": "example",
+    "number": "example-build-1",
+    "started": "2019-09-10T12:18:05.430+0000",
+    "durationMillis": 0,
+    "artifactoryPrincipal": "user",
+    "url": "https://my-ci.com",
+    "modules": [
+      {
+        "id": "org.example.demo:demo:2.2.0",
+        "artifacts": [
+          {
+            "type": "jar",
+            "sha1": "ayyyya9151a22cb3145538e523dbbaaaaaaaa",
+            "sha256": "aaaaaaaaa85f5c5093721f3ed0edda8ff8290yyyyyyyyyy",
+            "md5": "aaaaaacddea1724b0b69d8yyyyyyy",
+            "name": "demo-2.2.0.jar"
+          }
+        ]
+      }
+    ]
+  },
+  "uri": "https://my-artifactory-repo.com/api/build/example/example-build-1"
+}