Use a dedicated assign api for changing the upstream assignee

since updating it through edit doesn't work consistently

src/main/java/org/hibernate/infra/replicate/jira/service/jira/client/JiraRestClient.java

@@ -22,7 +22,6 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.quarkus.rest.client.reactive.ClientExceptionMapper;
-import io.quarkus.rest.client.reactive.ClientQueryParam;
 import io.quarkus.rest.client.reactive.jackson.ClientObjectMapper;
 import jakarta.ws.rs.Consumes;
 import jakarta.ws.rs.DELETE;
@@ -41,8 +40,10 @@
  * version (included), e.g.:
  */
 // so that we do not spam with all notifications ...
-// since `notifyUsers=false` does not apply to all requests and we've disabled notifications downstream
-// this query param is not sent anymore to allow automation updating upstream issues to work with a non-admin user.
+// since `notifyUsers=false` does not apply to all requests and we've disabled
+// notifications downstream
+// this query param is not sent anymore to allow automation updating upstream
+// issues to work with a non-admin user.
 // @ClientQueryParam(name = "notifyUsers", value = "false")
 public interface JiraRestClient {
 
@@ -150,7 +151,7 @@ JiraIssues find(@QueryParam("jql") String query, @QueryParam("startAt") int star
 
 	@GET
 	@Path("/issue/{issueKey}/transitions")
-	JiraTransitions availableTransitions(String issueKey);
+	JiraTransitions availableTransitions(@PathParam("issueKey") String issueKey);
 
 	@PUT
 	@Path("/issue/{issueKey}/archive")
@@ -172,6 +173,10 @@ JiraIssues find(@QueryParam("jql") String query, @QueryParam("startAt") int star
 	@Path("/version/{id}")
 	JiraVersion update(@PathParam("id") String id, JiraVersion version);
 
+	@PUT
+	@Path("/issue/{issueKey}/assignee")
+	void assign(@PathParam("issueKey") String id, JiraUser assignee);
+
 	@ClientObjectMapper
 	static ObjectMapper objectMapper(ObjectMapper defaultObjectMapper) {
 		return defaultObjectMapper.copy().setDefaultPropertyInclusion(JsonInclude.Include.NON_EMPTY);

src/main/java/org/hibernate/infra/replicate/jira/service/jira/client/JiraRestClientBuilder.java

@@ -281,6 +281,11 @@ public JiraVersion update(String id, JiraVersion version) {
 			return withRetry(() -> delegate.update(id, version));
 		}
 
+		@Override
+		public void assign(String id, JiraUser assignee) {
+			withRetry(() -> delegate.assign(id, assignee));
+		}
+
 		private static final int RETRIES = 5;
 		private static final Duration WAIT_BETWEEN_RETRIES = Duration.of(2, ChronoUnit.SECONDS);
 

src/main/java/org/hibernate/infra/replicate/jira/service/jira/handler/action/JiraAssigneeActionEventHandler.java

@@ -2,7 +2,6 @@
 
 import org.hibernate.infra.replicate.jira.service.jira.HandlerProjectContext;
 import org.hibernate.infra.replicate.jira.service.jira.model.action.JiraActionEvent;
-import org.hibernate.infra.replicate.jira.service.jira.model.rest.JiraFields;
 import org.hibernate.infra.replicate.jira.service.jira.model.rest.JiraIssue;
 import org.hibernate.infra.replicate.jira.service.jira.model.rest.JiraUser;
 import org.hibernate.infra.replicate.jira.service.reporting.ReportingConfig;
@@ -18,20 +17,20 @@ public JiraAssigneeActionEventHandler(ReportingConfig reportingConfig, HandlerPr
 	protected void doRun() {
 		JiraIssue issue = context.destinationJiraClient().getIssue(event.key);
 
-		JiraIssue updated = new JiraIssue();
-		updated.fields = JiraFields.empty();
+		JiraUser user = null;
 		if (issue.fields.assignee != null) {
 			String accountId = context.upstreamUser(
 					issue.fields.assignee.mappedIdentifier(context.projectGroup().users().mappedPropertyName()));
 
 			if (accountId != null) {
-				updated.fields.assignee = new JiraUser(accountId);
-
+				user = new JiraUser(accountId);
 			}
 		} else {
-			updated.fields.assignee = new JiraUser("-1");
+			user = new JiraUser("-1");
+		}
+		if (user != null) {
+			context.sourceJiraClient().assign(toSourceKey(event.key), user);
 		}
-		context.sourceJiraClient().update(toSourceKey(event.key), updated);
 	}
 
 	@Override

src/test/java/org/hibernate/infra/replicate/jira/mock/SampleJiraRestClient.java

@@ -229,6 +229,11 @@ public JiraVersion update(String id, JiraVersion version) {
 		return version;
 	}
 
+	@Override
+	public void assign(String id, JiraUser assignee) {
+		// ok
+	}
+
 	private JiraIssueLink sampleIssueLink(Long id) {
 		try {
 			return objectMapper.readValue("""