feat(model-server): implement /repositories/{repo}/branches/{branch} with failIfExists=true

Author: abstraktor

model-server-openapi/specifications/model-server-v2.yaml

@@ -359,6 +359,13 @@ paths:
           required: false
           schema:
             type: boolean
+            default: false
+        - name: failIfExists
+          in: "query"
+          required: false
+          schema:
+            type: boolean
+            default: false
       # this was autogenerated but will break tests
       # we need to manually design the content to allow
       # type safe access on our APIs
@@ -372,6 +379,12 @@ paths:
       responses:
         "200":
           $ref: '#/components/responses/versionDelta'
+        "409":
+            description: "Branch already exists and `failIfExists` was set to true."
+            content:
+                application/problem+json:
+                  schema:
+                      $ref: 'problem.yaml#/Problem'
         default:
           $ref: '#/components/responses/GeneralError'
   /repositories/{repository}/branches/{branch}/frontend:

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

@@ -396,8 +396,10 @@ class ModelReplicationServer(
         repository: String,
         branch: String,
         force: Boolean?,
+        failIfExists: Boolean?,
     ) {
         val force = force == true
+        val failIfExists = failIfExists == true
         checkPermission(ModelServerPermissionSchema.repository(repository).branch(branch).run { if (force) forcePush else push })
 
         val branchRef = repositoryId(repository).getBranchReference(branch)
@@ -408,23 +410,44 @@ class ModelReplicationServer(
             @OptIn(RequiresTransaction::class) // no transactions required for immutable store
             repositoriesManager.getStoreClient(RepositoryId(repository), true).putAll(objectsFromClient)
         }
+        suspend fun <R : Any> writeToBranch(writeAction: () -> R, onSuccess: suspend (R) -> Unit) {
+            val result =
+                @OptIn(RequiresTransaction::class)
+                runWrite {
+                    if (failIfExists && repositoriesManager.getVersionHash(branchRef) != null) {
+                        null
+                    } else {
+                        writeAction()
+                    }
+                }
+            if (result == null) {
+                call.respond(
+                    HttpStatusCode.Conflict,
+                    "Branch $branch in repository $repository already exists",
+                )
+            } else {
+                onSuccess(result)
+            }
+        }
 
         if (force) {
             @OptIn(RequiresTransaction::class)
-            runWrite {
+            writeToBranch({
                 repositoriesManager.forcePush(branchRef, deltaFromClient.versionHash)
-            }
-            call.respondDelta(RepositoryId(repository), deltaFromClient.versionHash, ObjectDeltaFilter(deltaFromClient.versionHash))
+            }, {
+                call.respondDelta(RepositoryId(repository), deltaFromClient.versionHash, ObjectDeltaFilter(deltaFromClient.versionHash))
+            })
         } else {
             // Run a merge outside a transaction to keep the transaction for the actual merge smaller.
             // If there are no concurrent pushes on the same branch, then all the work is done here.
             val preMergedVersion = repositoriesManager.mergeChangesWithoutPush(branchRef, deltaFromClient.versionHash)
 
             @OptIn(RequiresTransaction::class)
-            val mergedHash = runWrite {
+            writeToBranch({
                 repositoriesManager.mergeChanges(branchRef, preMergedVersion)
-            }
-            call.respondDelta(RepositoryId(repository), mergedHash, ObjectDeltaFilter(deltaFromClient.versionHash))
+            }, { mergedHash ->
+                call.respondDelta(RepositoryId(repository), mergedHash, ObjectDeltaFilter(deltaFromClient.versionHash))
+            })
         }
     }
 

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

@@ -41,6 +41,7 @@ import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.onEmpty
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.withTimeout
+import org.modelix.model.IVersion
 import org.modelix.model.ObjectDeltaFilter
 import org.modelix.model.api.IConceptReference
 import org.modelix.model.client2.ModelClientV2
@@ -49,6 +50,7 @@ import org.modelix.model.client2.runWrite
 import org.modelix.model.client2.useVersionStreamFormat
 import org.modelix.model.lazy.RepositoryId
 import org.modelix.model.server.api.BranchInfo
+import org.modelix.model.server.api.v2.VersionDelta
 import org.modelix.model.server.api.v2.VersionDeltaStream
 import org.modelix.model.server.api.v2.VersionDeltaStreamV2
 import org.modelix.model.server.installDefaultServerPlugins
@@ -603,6 +605,67 @@ class ModelReplicationServerTest {
         response shouldHaveStatus HttpStatusCode.NotFound
         problem.type shouldBe "/problems/object-value-not-found"
     }
+
+    @Test
+    fun `postRepositoryBranch with failIfExists true returns 409 if branch exists`() = runWithTestModelServer { _, fixture ->
+        // Arrange
+        val repositoryId = RepositoryId("repo1")
+        val branch = "existingBranch"
+        var version: IVersion? = null
+        @OptIn(RequiresTransaction::class)
+        fixture.repositoriesManager.getTransactionManager().runWrite {
+            version = fixture.repositoriesManager.createRepository(repositoryId, null)
+            fixture.repositoriesManager.forcePush(
+                repositoryId.getBranchReference(branch),
+                version.getContentHash(),
+            )
+        }
+
+        // Act
+        val client = createClient { install(ContentNegotiation) { json() } }
+        val response = client.post {
+            url {
+                appendPathSegments("v2", "repositories", repositoryId.id, "branches", branch)
+                parameters.append("failIfExists", "true")
+            }
+            useVersionStreamFormat()
+            contentType(ContentType.Application.Json)
+            setBody(VersionDelta(version!!.getContentHash(), null, objectsMap = mapOf<String, String>()))
+        }
+
+        // Assert
+        assertEquals(HttpStatusCode.Conflict, response.status)
+        assertContains(response.bodyAsText(), "already exists")
+    }
+
+    @Test
+    fun `postRepositoryBranch with failIfExists true creates branch if not exists`() = runWithTestModelServer { _, fixture ->
+        // Arrange
+        val repositoryId = RepositoryId("repo1")
+        val branch = "newBranch"
+
+        var version: IVersion? = null
+        @OptIn(RequiresTransaction::class)
+        fixture.repositoriesManager.getTransactionManager().runWrite {
+            version = fixture.repositoriesManager.createRepository(repositoryId, null)
+        }
+
+        // Act
+        val client = createClient { install(ContentNegotiation) { json() } }
+        val response = client.post {
+            url {
+                appendPathSegments("v2", "repositories", repositoryId.id, "branches", branch)
+                parameters.append("failIfExists", "true")
+            }
+            useVersionStreamFormat()
+            contentType(ContentType.Application.Json)
+            setBody(VersionDelta(version!!.getContentHash(), null, objectsMap = mapOf<String, String>()))
+        }
+
+        // Assert
+        assertEquals(HttpStatusCode.OK, response.status)
+        assertContains(response.bodyAsText(), version!!.getContentHash())
+    }
 }
 
 private fun ApplicationTestBuilder.jsonClient(): HttpClient = createClient {