fix(model-server): move the repository existence check and delete into a transaction

Author: benedekh

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

@@ -170,11 +170,11 @@ class ModelReplicationServer(val repositoriesManager: RepositoriesManager) {
             fun PipelineContext<Unit, ApplicationCall>.repositoryId() = call.repositoryId()
 
             val repositoryId = repositoryId()
-            if (!repositoriesManager.repositoryExists(repositoryId)) {
-                call.respond(HttpStatusCode.NotFound)
-            } else {
-                repositoriesManager.removeRepository(repositoryId)
+            val foundAndDeleted = repositoriesManager.removeRepository(repositoryId)
+            if (foundAndDeleted) {
                 call.respond(HttpStatusCode.NoContent)
+            } else {
+                call.respond(HttpStatusCode.NotFound)
             }
         }
 

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

@@ -145,15 +145,21 @@ class RepositoriesManager(val client: LocalModelClient) {
         }
     }
 
-    fun removeRepository(repository: RepositoryId) {
-        store.runTransaction {
+    fun removeRepository(repository: RepositoryId): Boolean {
+        return store.runTransaction {
+            if (!repositoryExists(repository)) {
+                return@runTransaction false
+            }
+
             for (branchName in getBranchNames(repository)) {
                 putVersionHash(repository.getBranchReference(branchName), null)
             }
             store.put(branchListKey(repository), null)
             val existingRepositories = getRepositories()
             val remainingRepositories = existingRepositories - repository
             store.put(REPOSITORIES_LIST_KEY, remainingRepositories.joinToString("\n") { it.id })
+
+            true
         }
     }