diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/UserDataConverter.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/UserDataConverter.java
index a854de99e37d..a57418793987 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/UserDataConverter.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/UserDataConverter.java
@@ -350,9 +350,9 @@ private void parseSentinelFieldValue(
           numericIncrementFieldValue =
               (com.google.firebase.firestore.FieldValue.NumericIncrementFieldValue) value;
       NumberValue operand = (NumberValue) parseQueryValue(numericIncrementFieldValue.getOperand());
-      NumericIncrementTransformOperation numericAdd =
+      NumericIncrementTransformOperation incrementOperation =
           new NumericIncrementTransformOperation(operand);
-      context.addToFieldTransforms(context.getPath(), numericAdd);
+      context.addToFieldTransforms(context.getPath(), incrementOperation);
 
     } else {
       throw Assert.fail("Unknown FieldValue type: %s", Util.typeName(value));
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java
index 2e5e5f6ff99e..5e5236e5f96d 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java
@@ -39,7 +39,6 @@
 import com.google.firebase.firestore.remote.TargetChange;
 import com.google.firebase.firestore.util.Logger;
 import com.google.protobuf.ByteString;
-
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/FieldMask.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/FieldMask.java
index 7b48459275ce..16573090fb5f 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/FieldMask.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/FieldMask.java
@@ -17,7 +17,6 @@
 import com.google.firebase.firestore.model.FieldPath;
 import com.google.firebase.firestore.model.value.FieldValue;
 import com.google.firebase.firestore.model.value.ObjectValue;
-
 import java.util.Set;
 
 /**
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/TransformMutation.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/TransformMutation.java
index 12a90088e726..abe82a999f25 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/TransformMutation.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/model/mutation/TransformMutation.java
@@ -25,7 +25,9 @@
 import com.google.firebase.firestore.model.value.FieldValue;
 import com.google.firebase.firestore.model.value.ObjectValue;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import javax.annotation.Nullable;
 
 /**
@@ -123,11 +125,11 @@ public MaybeDocument applyToLocalView(
 
   @Override
   public FieldMask getFieldMask() {
-    List<FieldPath> fieldMask = new ArrayList<>();
+    Set<FieldPath> fieldMask = new HashSet<>();
     for (FieldTransform transform : fieldTransforms) {
       fieldMask.add(transform.getFieldPath());
     }
-    return FieldMask.fromCollection(fieldMask);
+    return FieldMask.fromSet(fieldMask);
   }
 
   @Override
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteSerializer.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteSerializer.java
index d905496d51e2..44a2fa115cba 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteSerializer.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteSerializer.java
@@ -563,11 +563,11 @@ private DocumentTransform.FieldTransform encodeFieldTransform(FieldTransform fie
           .setRemoveAllFromArray(encodeArrayTransformElements(remove.getElements()))
           .build();
     } else if (transform instanceof NumericIncrementTransformOperation) {
-      NumericIncrementTransformOperation numericAdd =
+      NumericIncrementTransformOperation incrementOperation =
           (NumericIncrementTransformOperation) transform;
       return DocumentTransform.FieldTransform.newBuilder()
           .setFieldPath(fieldTransform.getFieldPath().canonicalString())
-          .setNumericAdd(encodeValue(numericAdd.getOperand()))
+          .setIncrement(encodeValue(incrementOperation.getOperand()))
           .build();
     } else {
       throw fail("Unknown transform: %s", transform);
@@ -605,9 +605,9 @@ private FieldTransform decodeFieldTransform(DocumentTransform.FieldTransform fie
             FieldPath.fromServerFormat(fieldTransform.getFieldPath()),
             new ArrayTransformOperation.Remove(
                 decodeArrayTransformElements(fieldTransform.getRemoveAllFromArray())));
-      case NUMERIC_ADD:
+      case INCREMENT:
         {
-          FieldValue operand = decodeValue(fieldTransform.getNumericAdd());
+          FieldValue operand = decodeValue(fieldTransform.getIncrement());
           hardAssert(
               operand instanceof NumberValue,
               "Expected NUMERIC_ADD transform to be of number type, but was %s",
@@ -615,7 +615,7 @@ private FieldTransform decodeFieldTransform(DocumentTransform.FieldTransform fie
           return new FieldTransform(
               FieldPath.fromServerFormat(fieldTransform.getFieldPath()),
               new NumericIncrementTransformOperation(
-                  (NumberValue) decodeValue(fieldTransform.getNumericAdd())));
+                  (NumberValue) decodeValue(fieldTransform.getIncrement())));
         }
       default:
         throw fail("Unknown FieldTransform proto: %s", fieldTransform);
diff --git a/firebase-firestore/src/proto/google/firestore/v1beta1/write.proto b/firebase-firestore/src/proto/google/firestore/v1beta1/write.proto
index c50868573e7f..5096d0e66db5 100644
--- a/firebase-firestore/src/proto/google/firestore/v1beta1/write.proto
+++ b/firebase-firestore/src/proto/google/firestore/v1beta1/write.proto
@@ -107,13 +107,13 @@ message DocumentTransform {
       //
       // This must be an integer or a double value.
       // If the field is not an integer or double, or if the field does not yet
-      // exist, the transformation will set the field to the given value.
+      // exist, the transformation will set the field to the given value.n
       // If either of the given value or the current field value are doubles,
       // both values will be interpreted as doubles. Double arithmetic and
       // representation of double values follow IEEE 754 semantics.
       // If there is positive/negative integer overflow, the field is resolved
       // to the largest magnitude positive/negative integer.
-      Value numeric_add = 3;
+      Value increment = 3;
 
       // Append the given elements in order if they are not already present in
       // the current field value.
diff --git a/firebase-firestore/src/test/java/com/google/firebase/firestore/local/LocalSerializerTest.java b/firebase-firestore/src/test/java/com/google/firebase/firestore/local/LocalSerializerTest.java
index 4a7bb69f7ada..52abbc51c0d5 100644
--- a/firebase-firestore/src/test/java/com/google/firebase/firestore/local/LocalSerializerTest.java
+++ b/firebase-firestore/src/test/java/com/google/firebase/firestore/local/LocalSerializerTest.java
@@ -17,6 +17,7 @@
 import static com.google.firebase.firestore.testutil.TestUtil.deleteMutation;
 import static com.google.firebase.firestore.testutil.TestUtil.deletedDoc;
 import static com.google.firebase.firestore.testutil.TestUtil.doc;
+import static com.google.firebase.firestore.testutil.TestUtil.field;
 import static com.google.firebase.firestore.testutil.TestUtil.fieldMask;
 import static com.google.firebase.firestore.testutil.TestUtil.key;
 import static com.google.firebase.firestore.testutil.TestUtil.map;
@@ -33,6 +34,7 @@
 import com.google.firebase.firestore.model.NoDocument;
 import com.google.firebase.firestore.model.SnapshotVersion;
 import com.google.firebase.firestore.model.UnknownDocument;
+import com.google.firebase.firestore.model.mutation.FieldMask;
 import com.google.firebase.firestore.model.mutation.Mutation;
 import com.google.firebase.firestore.model.mutation.MutationBatch;
 import com.google.firebase.firestore.model.mutation.PatchMutation;
@@ -70,7 +72,7 @@ public void testEncodesMutationBatch() {
         new PatchMutation(
             key("foo/bar"),
             TestUtil.wrapObject(map("a", "b")),
-            FieldMask.fromCollection(asList(field("a"))),
+            FieldMask.fromSet(Collections.singleton(field("a"))),
             com.google.firebase.firestore.model.mutation.Precondition.NONE);
     Mutation set = setMutation("foo/bar", map("a", "b", "num", 1));
     Mutation patch =