Fix regression for merge with increment

packages/firestore/CHANGELOG.md

@@ -1,4 +1,6 @@
 # Unreleased
+- [fixed] Fixed a regression introduced in v7.14.2 that incorrectly applied
+  a `FieldValue.increment` in combination with `set({...}, {merge: true})`.
 - [fixed] Firestore now rejects `onSnapshot()` listeners if they cannot be
   registered in IndexedDB. Previously, these errors crashed the client.
 - [fixed] Firestore now rejects write operations if they cannot be persisted

packages/firestore/src/api/field_value.ts

@@ -102,12 +102,17 @@ export class ArrayUnionFieldValueImpl extends FieldValueImpl {
     // Although array transforms are used with writes, the actual elements
     // being uniomed or removed are not considered writes since they cannot
     // contain any FieldValue sentinels, etc.
-    const parseContext = context.contextWith({
-      dataSource: UserDataSource.Argument,
-      methodName: this._methodName
-    });
+    const parseContext = new ParseContext(
+      {
+        dataSource: UserDataSource.Argument,
+        methodName: this._methodName,
+        arrayElement: true
+      },
+      context.databaseId,
+      context.serializer
+    );
     const parsedElements = this._elements.map(
-      (element, i) => parseData(element, parseContext.childContextForArray(i))!
+      element => parseData(element, parseContext)!
     );
     const arrayUnion = new ArrayUnionTransformOperation(parsedElements);
     return new FieldTransform(context.path!, arrayUnion);
@@ -128,12 +133,17 @@ export class ArrayRemoveFieldValueImpl extends FieldValueImpl {
     // Although array transforms are used with writes, the actual elements
     // being unioned or removed are not considered writes since they cannot
     // contain any FieldValue sentinels, etc.
-    const parseContext = context.contextWith({
-      dataSource: UserDataSource.Argument,
-      methodName: this._methodName
-    });
+    const parseContext = new ParseContext(
+      {
+        dataSource: UserDataSource.Argument,
+        methodName: this._methodName,
+        arrayElement: true
+      },
+      context.databaseId,
+      context.serializer
+    );
     const parsedElements = this._elements.map(
-      (element, i) => parseData(element, parseContext.childContextForArray(i))!
+      element => parseData(element, parseContext)!
     );
     const arrayUnion = new ArrayRemoveTransformOperation(parsedElements);
     return new FieldTransform(context.path!, arrayUnion);
@@ -151,8 +161,15 @@ export class NumericIncrementFieldValueImpl extends FieldValueImpl {
   }
 
   toFieldTransform(context: ParseContext): FieldTransform {
-    context.contextWith({ methodName: this._methodName });
-    const operand = parseData(this._operand, context)!;
+    const parseContext = new ParseContext(
+      {
+        dataSource: UserDataSource.Argument,
+        methodName: this._methodName
+      },
+      context.databaseId,
+      context.serializer
+    );
+    const operand = parseData(this._operand, parseContext)!;
     const numericIncrement = new NumericIncrementTransformOperation(
       context.serializer,
       operand

packages/firestore/src/api/user_data_reader.ts

@@ -140,9 +140,12 @@ interface ContextSettings {
    * nonempty path (indicating the context represents a nested location within
    * the data).
    */
-  readonly path: FieldPath | null;
-  /** Whether or not this context corresponds to an element of an array. */
-  readonly arrayElement: boolean;
+  readonly path?: FieldPath;
+  /**
+   * Whether or not this context corresponds to an element of an array.
+   * If not set, elements are treated as if they were outside of arrays.
+   */
+  readonly arrayElement?: boolean;
 }
 
 /** A "context" object passed around while parsing user data. */
@@ -181,7 +184,7 @@ export class ParseContext {
     this.fieldMask = fieldMask || [];
   }
 
-  get path(): FieldPath | null {
+  get path(): FieldPath | undefined {
     return this.settings.path;
   }
 
@@ -201,28 +204,28 @@ export class ParseContext {
   }
 
   childContextForField(field: string): ParseContext {
-    const childPath = this.path == null ? null : this.path.child(field);
+    const childPath = this.path?.child(field);
     const context = this.contextWith({ path: childPath, arrayElement: false });
     context.validatePathSegment(field);
     return context;
   }
 
   childContextForFieldPath(field: FieldPath): ParseContext {
-    const childPath = this.path == null ? null : this.path.child(field);
+    const childPath = this.path?.child(field);
     const context = this.contextWith({ path: childPath, arrayElement: false });
     context.validatePath();
     return context;
   }
 
   childContextForArray(index: number): ParseContext {
     // TODO(b/34871131): We don't support array paths right now; so make path
-    // null.
-    return this.contextWith({ path: null, arrayElement: true });
+    // undefined.
+    return this.contextWith({ path: undefined, arrayElement: true });
   }
 
   createError(reason: string): Error {
     const fieldDescription =
-      this.path === null || this.path.isEmpty()
+      !this.path || this.path.isEmpty()
         ? ''
         : ` (found in field ${this.path.toString()})`;
     return new FirestoreError(
@@ -246,7 +249,7 @@ export class ParseContext {
   private validatePath(): void {
     // TODO(b/34871131): Remove null check once we have proper paths for fields
     // within arrays.
-    if (this.path === null) {
+    if (!this.path) {
       return;
     }
     for (let i = 0; i < this.path.length; i++) {

packages/firestore/test/integration/api/numeric_transforms.test.ts

@@ -1,6 +1,6 @@
 /**
  * @license
- * Copyright 2018 Google Inc.
+ * Copyright 2018 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -140,6 +140,14 @@ apiDescribe('Numeric Transforms:', (persistence: boolean) => {
     });
   });
 
+  it('increments with set() and merge:true', async () => {
+    await withTestSetup(async () => {
+      await writeInitialData({ sum: 1 });
+      await docRef.set({ sum: FieldValue.increment(1337) }, { merge: true });
+      await expectLocalAndRemoteValue(1338);
+    });
+  });
+
   it('multiple double increments', async () => {
     await withTestSetup(async () => {
       await writeInitialData({ sum: 0.0 });