Shared Tree: Schema FormatV2 and codecs

.changeset/spotty-bottles-rest.md

@@ -5,7 +5,7 @@
 ---
 Persisted metadata for Shared Tree schemas
 
-The persisted metadata feature for Shared Tree allows an application author to write metadata along with the schema. This feature is supported for both object node and field schemas.
+The persisted metadata feature for Shared Tree allows an application author to write document-persisted metadata along with the schema. This feature is supported for both object node and field schemas.
 
 #### Using the persisted metadata feature
 
@@ -32,9 +32,9 @@ const tree = configuredSharedTree({
 }).create(runtime);
 
 export const MyContainerSchema = {
-  initialObjects: {
-    appData: tree,
-  },
+    initialObjects: {
+        appData: tree,
+    },
 } satisfies ContainerSchema;
 ```
 

packages/dds/tree/src/core/schema-stored/schema.ts

@@ -232,49 +232,44 @@ export class ObjectNodeStoredSchema extends TreeNodeStoredSchema {
 	}
 
 	public override encodeV1(): TreeNodeSchemaDataFormatV1 {
-		const fieldsObject: Record<string, FieldSchemaFormat> = Object.create(null);
-		// Sort fields to ensure output is identical for for equivalent schema (since field order is not considered significant).
-		// This makes comparing schema easier, and ensures chunk reuse for schema summaries isn't needlessly broken.
-		for (const key of [...this.objectNodeFields.keys()].sort()) {
-			Object.defineProperty(fieldsObject, key, {
-				enumerable: true,
-				configurable: true,
-				writable: true,
-				value: encodeFieldSchemaV1(
-					this.objectNodeFields.get(key) ?? fail(0xae7 /* missing field */),
-				),
-			});
-		}
+		const fieldsObject: Record<string, FieldSchemaFormat> =
+			this.encodeFieldsObject(encodeFieldSchemaV1);
+
 		return {
 			object: fieldsObject,
 		};
 	}
 
 	public override encodeV2(): TreeNodeSchemaDataFormatV2 {
+		const fieldsObject: Record<string, FieldSchemaFormat> =
+			this.encodeFieldsObject(encodeFieldSchemaV2);
+		const kind = { object: fieldsObject };
+
+		// Omit metadata from the output if it is undefined
+		return this.metadata !== undefined ? { kind, metadata: this.metadata } : { kind };
+	}
+
+	public override getFieldSchema(field: FieldKey): TreeFieldStoredSchema {
+		return this.objectNodeFields.get(field) ?? storedEmptyFieldSchema;
+	}
+
+	private encodeFieldsObject(
+		encodeFieldSchema: (storedFieldSchema: TreeFieldStoredSchema) => FieldSchemaFormat,
+	): Record<string, FieldSchemaFormat> {
 		const fieldsObject: Record<string, FieldSchemaFormat> = Object.create(null);
 		// Sort fields to ensure output is identical for for equivalent schema (since field order is not considered significant).
 		// This makes comparing schema easier, and ensures chunk reuse for schema summaries isn't needlessly broken.
 		for (const key of [...this.objectNodeFields.keys()].sort()) {
-			const value = encodeFieldSchemaV2(
-				this.objectNodeFields.get(key) ?? fail(0xae7 /* missing field */),
-			);
-
 			Object.defineProperty(fieldsObject, key, {
 				enumerable: true,
 				configurable: true,
 				writable: true,
-				value,
+				value: encodeFieldSchema(
+					this.objectNodeFields.get(key) ?? fail(0xae7 /* missing field */),
+				),
 			});
 		}
-
-		const kind = { object: fieldsObject };
-
-		// Omit metadata from the output if it is undefined
-		return this.metadata !== undefined ? { kind, metadata: this.metadata } : { kind };
-	}
-
-	public override getFieldSchema(field: FieldKey): TreeFieldStoredSchema {
-		return this.objectNodeFields.get(field) ?? storedEmptyFieldSchema;
+		return fieldsObject;
 	}
 }
 

packages/dds/tree/src/feature-libraries/schema-index/codec.ts

@@ -22,8 +22,6 @@ import {
 	decodeFieldSchema,
 	encodeFieldSchemaV1,
 	encodeFieldSchemaV2,
-	type schemaFormatV1,
-	type schemaFormatV2,
 	storedSchemaDecodeDispatcher,
 } from "../../core/index.js";
 import { brand, type JsonCompatible } from "../../util/index.js";
@@ -89,18 +87,8 @@ export function encodeRepo(repo: TreeStoredSchema, version: SchemaVersion): Json
 }
 
 function encodeRepoV1(repo: TreeStoredSchema): FormatV1 {
-	const nodeSchema: Record<string, schemaFormatV1.TreeNodeSchemaDataFormat> =
-		Object.create(null);
+	const nodeSchema = encodeNodeSchema(repo, (schema) => schema.encodeV1());
 	const rootFieldSchema = encodeFieldSchemaV1(repo.rootFieldSchema);
-	for (const name of [...repo.nodeSchema.keys()].sort()) {
-		const schema = repo.nodeSchema.get(name) ?? fail(0xb28 /* missing schema */);
-		Object.defineProperty(nodeSchema, name, {
-			enumerable: true,
-			configurable: true,
-			writable: true,
-			value: schema.encodeV1(),
-		});
-	}
 	return {
 		version: SchemaVersion.v1,
 		nodes: nodeSchema,
@@ -109,23 +97,37 @@ function encodeRepoV1(repo: TreeStoredSchema): FormatV1 {
 }
 
 function encodeRepoV2(repo: TreeStoredSchema): FormatV2 {
-	const nodeSchema: Record<string, schemaFormatV2.TreeNodeSchemaDataFormat> =
-		Object.create(null);
+	const nodeSchema = encodeNodeSchema(repo, (schema) => schema.encodeV2());
 	const rootFieldSchema = encodeFieldSchemaV2(repo.rootFieldSchema);
+	return {
+		version: SchemaVersion.v2,
+		nodes: nodeSchema,
+		root: rootFieldSchema,
+	};
+}
+
+/**
+ * Shared logic for encoding node schemas.
+ * @param repo - The stored schema to encode.
+ * @param encodeValue - A function which encodes a single node schema.
+ * @returns The encoded node schema.
+ */
+function encodeNodeSchema<TFormat>(
+	repo: TreeStoredSchema,
+	encodeValue: (schema: TreeNodeStoredSchema) => TFormat,
+): Record<string, TFormat> {
+	const nodeSchema: Record<string, TFormat> = Object.create(null);
 	for (const name of [...repo.nodeSchema.keys()].sort()) {
 		const schema = repo.nodeSchema.get(name) ?? fail(0xb28 /* missing schema */);
 		Object.defineProperty(nodeSchema, name, {
 			enumerable: true,
 			configurable: true,
 			writable: true,
-			value: schema.encodeV2(),
+			value: encodeValue(schema),
 		});
 	}
-	return {
-		version: SchemaVersion.v2,
-		nodes: nodeSchema,
-		root: rootFieldSchema,
-	};
+
+	return nodeSchema;
 }
 
 function decodeV1(f: FormatV1): TreeStoredSchema {

packages/dds/tree/src/test/shared-tree/sharedTree.spec.ts

@@ -2244,10 +2244,7 @@ describe("SharedTree", () => {
 	describe("Shared Tree format v5 enablement via `configuredSharedTree`", () => {
 		it("can create a SharedTree with format v5 enabled", async () => {
 			// Create and initialize the runtime factory
-			const runtime = new MockFluidDataStoreRuntime({
-				idCompressor: createIdCompressor(),
-				attachState: AttachState.Detached,
-			});
+			const runtime = new MockSharedTreeRuntime();
 
 			// Enable Shared Tree format v5, which corresponds to schema format v2. Create a Shared Tree instance.
 			const tree = configuredSharedTree({