chore: Update codebase formatting tool and introduce metalava (#1695)

This PR includes:

* A new tools module that is only used to run metalava and generate api.txt.
* Introduce spotless plugin to run auto format for potential kotlin files.

Author: wu-hui

.kokoro/build.sh

@@ -52,7 +52,7 @@ test)
     RETURN_CODE=$?
     ;;
 lint)
-    mvn com.coveo:fmt-maven-plugin:check -B -ntp
+    mvn com.coveo:fmt-maven-plugin:check -B -ntp && mvn -pl google-cloud-firestore spotless:check -B -ntp
     RETURN_CODE=$?
     ;;
 javadoc)

google-cloud-firestore/pom.xml

@@ -214,6 +214,24 @@
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>flatten-maven-plugin</artifactId>
       </plugin>
+      <plugin>
+        <groupId>com.diffplug.spotless</groupId>
+        <artifactId>spotless-maven-plugin</artifactId>
+        <version>2.43.0</version>
+        <configuration>
+          <kotlin>
+            <includes>
+              <include>src/main/java/**/*.kt</include>
+              <include>src/test/java/**/*.kt</include>
+            </includes>
+
+            <ktfmt>
+              <version>0.46</version> <!-- optional -->
+              <style>GOOGLE</style> <!-- optional, other options are DROPBOX, GOOGLE and KOTLINLANG -->
+            </ktfmt>
+          </kotlin>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 

google-cloud-firestore/src/main/java/com/google/cloud/firestore/GeoPoint.java

@@ -76,6 +76,7 @@ LatLng toProto() {
   public String toString() {
     return "GeoPoint { latitude=" + this.latitude + ", longitude=" + this.longitude + " }";
   }
+
   /**
    * Returns true if this GeoPoint is equal to the provided object.
    *

google-cloud-firestore/src/main/java/com/google/cloud/firestore/QuerySnapshot.java

@@ -151,6 +151,7 @@ public int hashCode() {
       }
     };
   }
+
   /**
    * Returns the query for the snapshot.
    *

google-cloud-firestore/src/main/java/com/google/cloud/firestore/ReadTimeTransaction.java

@@ -57,7 +57,7 @@ public boolean hasTransactionId() {
   public ApiFuture<DocumentSnapshot> get(@Nonnull DocumentReference documentRef) {
     Tracing.getTracer().getCurrentSpan().addAnnotation(TraceUtil.SPAN_NAME_GETDOCUMENT);
     return ApiFutures.transform(
-        firestore.getAll(new DocumentReference[] {documentRef}, /*fieldMask=*/ null, readTime),
+        firestore.getAll(new DocumentReference[] {documentRef}, /* fieldMask= */ null, readTime),
         snapshots -> snapshots.isEmpty() ? null : snapshots.get(0),
         MoreExecutors.directExecutor());
   }
@@ -66,14 +66,14 @@ public ApiFuture<DocumentSnapshot> get(@Nonnull DocumentReference documentRef) {
   @Override
   public ApiFuture<List<DocumentSnapshot>> getAll(
       @Nonnull DocumentReference... documentReferences) {
-    return firestore.getAll(documentReferences, /*fieldMask=*/ null, readTime);
+    return firestore.getAll(documentReferences, /* fieldMask= */ null, readTime);
   }
 
   @Nonnull
   @Override
   public ApiFuture<List<DocumentSnapshot>> getAll(
       @Nonnull DocumentReference[] documentReferences, @Nullable FieldMask fieldMask) {
-    return firestore.getAll(documentReferences, /*fieldMask=*/ null, readTime);
+    return firestore.getAll(documentReferences, /* fieldMask= */ null, readTime);
   }
 
   @Nonnull

google-cloud-firestore/src/main/java/com/google/cloud/firestore/ServerSideTransaction.java

@@ -151,9 +151,9 @@ public ApiFuture<DocumentSnapshot> get(@Nonnull DocumentReference documentRef) {
     return ApiFutures.transform(
         firestore.getAll(
             new DocumentReference[] {documentRef},
-            /*fieldMask=*/ null,
+            /* fieldMask= */ null,
             transactionId,
-            /*readTime=*/ null),
+            /* readTime= */ null),
         snapshots -> snapshots.isEmpty() ? null : snapshots.get(0),
         MoreExecutors.directExecutor());
   }
@@ -170,7 +170,7 @@ public ApiFuture<List<DocumentSnapshot>> getAll(
       @Nonnull DocumentReference... documentReferences) {
     Preconditions.checkState(isEmpty(), READ_BEFORE_WRITE_ERROR_MSG);
     return firestore.getAll(
-        documentReferences, /*fieldMask=*/ null, transactionId, /*readTime=*/ null);
+        documentReferences, /* fieldMask= */ null, transactionId, /* readTime= */ null);
   }
 
   /**
@@ -186,7 +186,7 @@ public ApiFuture<List<DocumentSnapshot>> getAll(
   public ApiFuture<List<DocumentSnapshot>> getAll(
       @Nonnull DocumentReference[] documentReferences, @Nullable FieldMask fieldMask) {
     Preconditions.checkState(isEmpty(), READ_BEFORE_WRITE_ERROR_MSG);
-    return firestore.getAll(documentReferences, fieldMask, transactionId, /*readTime=*/ null);
+    return firestore.getAll(documentReferences, fieldMask, transactionId, /* readTime= */ null);
   }
 
   /**
@@ -199,7 +199,7 @@ public ApiFuture<List<DocumentSnapshot>> getAll(
   @Nonnull
   public ApiFuture<QuerySnapshot> get(@Nonnull Query query) {
     Preconditions.checkState(isEmpty(), READ_BEFORE_WRITE_ERROR_MSG);
-    return query.get(transactionId, /*readTime=*/ null);
+    return query.get(transactionId, /* readTime= */ null);
   }
 
   /**

google-cloud-firestore/src/main/java/com/google/cloud/firestore/ServerSideTransactionRunner.java

@@ -251,6 +251,7 @@ private static boolean isRetryableTransactionError(ApiException exception) {
         return false;
     }
   }
+
   /** Rolls the transaction back and returns the error. */
   private ApiFuture<T> rollbackAndReject(final Throwable throwable) {
     final SettableApiFuture<T> failedTransaction = SettableApiFuture.create();

google-cloud-firestore/src/test/java/com/google/cloud/firestore/LocalFirestoreHelper.java

@@ -375,7 +375,7 @@ public static Answer<RunAggregationQueryResponse> countQueryResponse(
         new RunAggregationQueryResponse[] {
           createCountQueryResponse(count, readTime),
         },
-        /*throwable=*/ null);
+        /* throwable= */ null);
   }
 
   public static Answer<RunAggregationQueryResponse> countQueryResponse(Throwable throwable) {
@@ -388,7 +388,7 @@ public static Answer<RunAggregationQueryResponse> aggregationQueryResponses(
         new RunAggregationQueryResponse[] {
           createCountQueryResponse(count1, null), createCountQueryResponse(count2, null),
         },
-        /*throwable=*/ null);
+        /* throwable= */ null);
   }
 
   public static Answer<RunAggregationQueryResponse> aggregationQueryResponses(
@@ -1209,6 +1209,7 @@ public RequestResponsePair(
       this.response = response;
     }
   }
+
   /**
    * Contains a map of request/response pairs that are used to create stub responses when
    * `sendRequest()` is called.

google-cloud-firestore/src/test/java/com/google/cloud/firestore/MapperTest.java

@@ -949,11 +949,11 @@ public void setValue(String value) {
   }
 
   private static <T> T deserialize(String jsonString, Class<T> clazz) {
-    return deserialize(jsonString, clazz, /*docRef=*/ null);
+    return deserialize(jsonString, clazz, /* docRef= */ null);
   }
 
   private static <T> T deserialize(Map<String, Object> json, Class<T> clazz) {
-    return deserialize(json, clazz, /*docRef=*/ null);
+    return deserialize(json, clazz, /* docRef= */ null);
   }
 
   private static <T> T deserialize(String jsonString, Class<T> clazz, DocumentReference docRef) {

tools/README.md

@@ -0,0 +1,5 @@
+
+Run below command to generate api.txt
+```bash
+mvn exec:java -Dexec.mainClass="com.android.tools.metalava.Driver" -Dexec.args="--source-path ../google-cloud-firestore/src/main/java --hide HiddenSuperclass --hide HiddenAbstractMethod --api api.txt --format=v2"
+```