fix(model-server): respond with 404 when querying a non-existent branch

Author: mhuster23

model-server/src/main/kotlin/org/modelix/model/server/handlers/ModelReplicationServer.kt

@@ -287,9 +287,9 @@ class ModelReplicationServer(
         val branchRef = repositoryId(repository).getBranchReference(branch)
         checkPermission(ModelServerPermissionSchema.branch(branchRef).query)
         runWithRepository(repository) {
-            val version = repositoriesManager.getVersion(branchRef)
+            val version = repositoriesManager.getVersion(branchRef) ?: throw BranchNotFoundException(branchRef)
             LOG.trace("Running query on {} @ {}", branchRef, version)
-            val initialTree = version!!.getTree()
+            val initialTree = version.getTree()
             val otBranch = OTBranch(
                 PBranch(initialTree, modelClient.idGenerator),
                 modelClient.idGenerator,

model-server/src/test/kotlin/org/modelix/model/server/handlers/ModelReplicationServerTest.kt

@@ -28,6 +28,7 @@ import io.ktor.client.plugins.defaultRequest
 import io.ktor.client.request.accept
 import io.ktor.client.request.delete
 import io.ktor.client.request.get
+import io.ktor.client.request.post
 import io.ktor.client.statement.bodyAsText
 import io.ktor.http.ContentType
 import io.ktor.http.HttpHeaders
@@ -191,6 +192,15 @@ class ModelReplicationServerTest {
         }
     }
 
+    @Test
+    fun `responds with 404 when querying non-existent branch`() = runWithTestModelServer { _, _ ->
+        val repositoryId = "abc"
+        val branch = "non-existing-branch"
+        val response = client.post("/v2/repositories/$repositoryId/branches/$branch/query")
+        response shouldHaveStatus 404
+        assertContains(response.bodyAsText(), "Branch '$branch' does not exist in repository '$repositoryId'")
+    }
+
     @Test
     fun `successfully deletes existing branches`() {
         val repositoryId = RepositoryId("repo1")