fix(gke): resolve version aliases on UpdateCluster desired versions

docs/services/gke.md

@@ -176,6 +176,11 @@ analysis, since floci-gcp has no real infrastructure behind them to inspect:
   omitted; with several it is required, and a request without it is rejected
   as `400 INVALID_ARGUMENT` rather than silently upgrading pools the caller
   did not name.
+  `desiredMasterVersion` and `desiredNodeVersion` accept the same aliases as
+  `UpdateMaster` below, with the documented difference that `-` on the node side
+  picks the cluster's current master version rather than the server default. This
+  is what `gcloud container clusters upgrade` sends when no `--cluster-version` is
+  given, so both forms of that command leave the cluster on a real version.
 - `UpdateMaster` moves only the control plane: `currentMasterVersion` changes and
   `currentNodeVersion` and every node pool's `version` stay as they were, as in real
   GKE, where the master and node pools upgrade independently. `masterVersion` is

src/main/java/io/floci/gcp/services/gke/GkeService.java

@@ -328,19 +328,23 @@ public StoredOperation updateCluster(String project, String location, String clu
                 // assigning first would leave a rejected request's version behind on it.
                 List<StoredNodePool> targets =
                         nodeVersionUpdateTargets(project, location, clusterId, updateMap);
-                cluster.setCurrentNodeVersion(desiredNodeVersion);
+                String nodeVersion = resolveNodeVersion(desiredNodeVersion, cluster);
+                cluster.setCurrentNodeVersion(nodeVersion);
                 // The pool carries its own `version`, and GetNodePool/ListNodePools read it from
                 // the pool store, so moving only the cluster aggregate would report the new
                 // version on the cluster while the pool still reported the old one.
                 for (StoredNodePool pool : targets) {
-                    pool.setVersion(desiredNodeVersion);
+                    pool.setVersion(nodeVersion);
                     pool.setEtag(newFingerprint());
                     nodePoolStore.put(nodePoolKey(project, location, clusterId, pool.getName()), pool);
                 }
             }
             String desiredMasterVersion = (String) updateMap.get("desiredMasterVersion");
             if (desiredMasterVersion != null) {
-                cluster.setCurrentMasterVersion(desiredMasterVersion);
+                // Same aliases as UpdateMaster; gcloud sends "-" here for `clusters upgrade
+                // --master` without --cluster-version, which stored verbatim left the cluster
+                // reporting version "-".
+                cluster.setCurrentMasterVersion(resolveMasterVersion(desiredMasterVersion));
             }
             if (updateMap.get("desiredLocations") != null) {
                 cluster.setLocations(stringListField(updateMap, "desiredLocations", cluster.getLocations()));
@@ -824,6 +828,15 @@ private static String resolveMasterVersion(String requested) {
         return requested;
     }
 
+    /** {@code desired_node_version} documents the same spellings as {@code master_version}
+     * with one difference: {@code "-"} "picks the Kubernetes master version", the cluster's
+     * current control plane version, not the server default that {@code "-"} means on the master
+     * field. The proto allows one {@code ClusterUpdate} field per request, so this reads the
+     * master version as stored, not one the same request might also be changing. */
+    private static String resolveNodeVersion(String requested, StoredCluster cluster) {
+        return "-".equals(requested) ? cluster.getCurrentMasterVersion() : resolveMasterVersion(requested);
+    }
+
     /** The node pools an {@code UpdateCluster} carrying {@code desiredNodeVersion} upgrades.
      *
      * <p>{@code desired_node_version} upgrades the single pool named by {@code

src/test/java/io/floci/gcp/services/gke/GkeServiceTest.java

@@ -732,6 +732,48 @@ void desiredNodePoolIdDoesNotLeakIntoClusterState() {
         assertNull(service.getCluster(PROJECT, LOCATION, "no-leak").getExtraConfig().get("nodePoolId"));
     }
 
+    @Test
+    void updateClusterResolvesDesiredMasterVersionAliases() {
+        // gcloud `container clusters upgrade C --master` sends desiredMasterVersion "-" when no
+        // --cluster-version is given; stored verbatim, the cluster then reported version "-".
+        service.createCluster(PROJECT, LOCATION, Map.of("name", "master-alias",
+                "initialClusterVersion", "1.29.0-gke.1"));
+        String advertised = (String) service.getServerConfig().get("defaultClusterVersion");
+
+        service.updateCluster(PROJECT, LOCATION, "master-alias", Map.of("desiredMasterVersion", "-"));
+        assertEquals(advertised, service.getCluster(PROJECT, LOCATION, "master-alias").getCurrentMasterVersion());
+
+        service.updateCluster(PROJECT, LOCATION, "master-alias", Map.of("desiredMasterVersion", "1.29.0-gke.1"));
+        service.updateCluster(PROJECT, LOCATION, "master-alias", Map.of("desiredMasterVersion", "latest"));
+        assertEquals(advertised, service.getCluster(PROJECT, LOCATION, "master-alias").getCurrentMasterVersion());
+
+        // An explicit version is still stored verbatim, and node versions do not move with the master.
+        service.updateCluster(PROJECT, LOCATION, "master-alias", Map.of("desiredMasterVersion", "1.31.5-gke.1"));
+        StoredCluster cluster = service.getCluster(PROJECT, LOCATION, "master-alias");
+        assertEquals("1.31.5-gke.1", cluster.getCurrentMasterVersion());
+        assertEquals("1.29.0-gke.1", cluster.getCurrentNodeVersion());
+    }
+
+    @Test
+    void updateClusterResolvesDesiredNodeVersionAliasesAgainstTheMaster() {
+        // desired_node_version documents the same aliases as the master field, except that "-"
+        // "picks the Kubernetes master version": the cluster's control plane, not the server default.
+        service.createCluster(PROJECT, LOCATION, Map.of("name", "node-alias",
+                "initialClusterVersion", "1.29.0-gke.1"));
+        String advertised = (String) service.getServerConfig().get("defaultClusterVersion");
+        assertNotEquals(advertised, "1.29.0-gke.1");
+
+        service.updateCluster(PROJECT, LOCATION, "node-alias", Map.of("desiredNodeVersion", "latest"));
+        assertEquals(advertised, service.getCluster(PROJECT, LOCATION, "node-alias").getCurrentNodeVersion());
+        assertEquals(advertised, service.getNodePool(PROJECT, LOCATION, "node-alias", "default-pool").getVersion());
+
+        service.updateCluster(PROJECT, LOCATION, "node-alias", Map.of("desiredNodeVersion", "-"));
+        StoredCluster cluster = service.getCluster(PROJECT, LOCATION, "node-alias");
+        assertEquals("1.29.0-gke.1", cluster.getCurrentMasterVersion());
+        assertEquals("1.29.0-gke.1", cluster.getCurrentNodeVersion());
+        assertEquals("1.29.0-gke.1", service.getNodePool(PROJECT, LOCATION, "node-alias", "default-pool").getVersion());
+    }
+
     @Test
     void updateClusterMergesDesiredFieldsIntoExtraConfig() {
         service.createCluster(PROJECT, LOCATION, Map.of("name", "updatable"));

src/test/java/io/floci/gcp/services/gke/GkeUpdateClusterRestIntegrationTest.java

@@ -0,0 +1,73 @@
+package io.floci.gcp.services.gke;
+
+import io.quarkus.test.junit.QuarkusTest;
+import org.junit.jupiter.api.Test;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
+
+/**
+ * {@code ClusterManager.UpdateCluster} over REST ({@code PUT .../clusters/{id}}), with the
+ * request shapes gcloud actually sends for {@code container clusters upgrade}.
+ */
+@QuarkusTest
+class GkeUpdateClusterRestIntegrationTest {
+
+    private static final String PROJECT = "gke-update-cluster-it";
+    private static final String LOCATION = "us-central1";
+    private static final String BASE = "/container/v1/projects/" + PROJECT + "/locations/" + LOCATION;
+
+    @Test
+    void gcloudUpgradeWithoutAVersionSendsDashAndGetsARealVersionBack() {
+        String cluster = "gcloud-upgrade";
+        String clusterPath = BASE + "/clusters/" + cluster;
+
+        given()
+                .contentType("application/json")
+                .body("{\"cluster\":{\"name\":\"" + cluster + "\",\"initialClusterVersion\":\"1.29.0-gke.1\"}}")
+                .when().post(BASE + "/clusters")
+                .then()
+                .statusCode(200);
+
+        String advertised = given()
+                .when().get(BASE + "/serverConfig")
+                .then()
+                .statusCode(200)
+                .extract().path("defaultClusterVersion");
+
+        // `gcloud container clusters upgrade C --master` with no --cluster-version.
+        given()
+                .contentType("application/json")
+                .body("{\"update\":{\"desiredMasterVersion\":\"-\"}}")
+                .when().put(clusterPath)
+                .then()
+                .statusCode(200)
+                .body("status", equalTo("DONE"));
+
+        given()
+                .when().get(clusterPath)
+                .then()
+                .statusCode(200)
+                .body("currentMasterVersion", equalTo(advertised))
+                .body("currentMasterVersion", not(equalTo("-")))
+                .body("currentNodeVersion", equalTo("1.29.0-gke.1"));
+
+        // `gcloud container clusters upgrade C --node-pool default-pool` with no --cluster-version:
+        // "-" on the node side means the cluster's master version.
+        given()
+                .contentType("application/json")
+                .body("{\"update\":{\"desiredNodeVersion\":\"-\",\"desiredNodePoolId\":\"default-pool\"}}")
+                .when().put(clusterPath)
+                .then()
+                .statusCode(200)
+                .body("status", equalTo("DONE"));
+
+        given()
+                .when().get(clusterPath)
+                .then()
+                .statusCode(200)
+                .body("currentNodeVersion", equalTo(advertised))
+                .body("nodePools[0].version", equalTo(advertised));
+    }
+}