fix:refactor compute and cloudshell credentials to pass quota project…

… to base class

oauth2_http/java/com/google/auth/oauth2/CloudShellCredentials.java

@@ -66,8 +66,9 @@ public static CloudShellCredentials create(int authPort) {
     return CloudShellCredentials.newBuilder().setAuthPort(authPort).build();
   }
 
-  private CloudShellCredentials(int authPort) {
-    this.authPort = authPort;
+  private CloudShellCredentials(Builder builder) {
+    super(builder);
+    this.authPort = builder.getAuthPort();
   }
 
   protected int getAuthPort() {
@@ -141,7 +142,7 @@ public int getAuthPort() {
     }
 
     public CloudShellCredentials build() {
-      return new CloudShellCredentials(authPort);
+      return new CloudShellCredentials(this);
     }
   }
 }

oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java

@@ -120,28 +120,23 @@ public class ComputeEngineCredentials extends GoogleCredentials
   private transient String serviceAccountEmail;
 
   /**
-   * Constructor with overridden transport.
+   * Constructor with builder
    *
-   * @param transportFactory HTTP transport factory, creates the transport used to get access
-   *     tokens.
-   * @param scopes scope strings for the APIs to be called. May be null or an empty collection.
-   * @param defaultScopes default scope strings for the APIs to be called. May be null or an empty
-   *     collection. Default scopes are ignored if scopes are provided.
+   * @param builder builder to use for constructing the credential
    */
-  private ComputeEngineCredentials(
-      HttpTransportFactory transportFactory,
-      Collection<String> scopes,
-      Collection<String> defaultScopes) {
-    super(/* accessToken= */ null, COMPUTE_REFRESH_MARGIN, COMPUTE_EXPIRATION_MARGIN);
+  private ComputeEngineCredentials(Builder builder) {
+    super(builder);
 
     this.transportFactory =
         firstNonNull(
-            transportFactory,
+            builder.getHttpTransportFactory(),
             getFromServiceLoader(HttpTransportFactory.class, OAuth2Utils.HTTP_TRANSPORT_FACTORY));
     this.transportFactoryClassName = this.transportFactory.getClass().getName();
+
+    Collection<String> scopes = builder.getScopes();
     // Use defaultScopes only when scopes don't exist.
     if (scopes == null || scopes.isEmpty()) {
-      scopes = defaultScopes;
+      scopes = builder.getDefaultScopes();
     }
     if (scopes == null) {
       this.scopes = ImmutableSet.<String>of();
@@ -155,14 +150,14 @@ private ComputeEngineCredentials(
   /** Clones the compute engine account with the specified scopes. */
   @Override
   public GoogleCredentials createScoped(Collection<String> newScopes) {
-    return new ComputeEngineCredentials(this.transportFactory, newScopes, null);
+    return toBuilder().setScopes(newScopes).build();
   }
 
   /** Clones the compute engine account with the specified scopes. */
   @Override
   public GoogleCredentials createScoped(
       Collection<String> newScopes, Collection<String> newDefaultScopes) {
-    return new ComputeEngineCredentials(this.transportFactory, newScopes, newDefaultScopes);
+    return toBuilder().setScopes(newScopes).setDefaultScopes(newDefaultScopes).build();
   }
 
   /**
@@ -171,7 +166,7 @@ public GoogleCredentials createScoped(
    * @return new ComputeEngineCredentials
    */
   public static ComputeEngineCredentials create() {
-    return new ComputeEngineCredentials(null, null, null);
+    return newBuilder().build();
   }
 
   public final Collection<String> getScopes() {
@@ -541,10 +536,16 @@ private String getDefaultServiceAccount() throws IOException {
   public static class Builder extends GoogleCredentials.Builder {
     private HttpTransportFactory transportFactory;
     private Collection<String> scopes;
+    private Collection<String> defaultScopes;
 
-    protected Builder() {}
+    protected Builder() {
+      // Override the default refresh and expiration margin set by OAuth2Credentials.Builder
+      this.refreshMargin = COMPUTE_REFRESH_MARGIN;
+      this.expirationMargin = COMPUTE_EXPIRATION_MARGIN;
+    }
 
     protected Builder(ComputeEngineCredentials credentials) {
+      this();
       this.transportFactory = credentials.transportFactory;
       this.scopes = credentials.scopes;
     }
@@ -559,6 +560,11 @@ public Builder setScopes(Collection<String> scopes) {
       return this;
     }
 
+    public Builder setDefaultScopes(Collection<String> defaultScopes) {
+      this.defaultScopes = defaultScopes;
+      return this;
+    }
+
     public HttpTransportFactory getHttpTransportFactory() {
       return transportFactory;
     }
@@ -567,8 +573,12 @@ public Collection<String> getScopes() {
       return scopes;
     }
 
+    public Collection<String> getDefaultScopes() {
+      return defaultScopes;
+    }
+
     public ComputeEngineCredentials build() {
-      return new ComputeEngineCredentials(transportFactory, scopes, null);
+      return new ComputeEngineCredentials(this);
     }
   }
 }

oauth2_http/java/com/google/auth/oauth2/OAuth2Credentials.java

@@ -637,8 +637,8 @@ public void run() {
   public static class Builder {
 
     private AccessToken accessToken;
-    private Duration refreshMargin = DEFAULT_REFRESH_MARGIN;
-    private Duration expirationMargin = DEFAULT_EXPIRATION_MARGIN;
+    protected Duration refreshMargin = DEFAULT_REFRESH_MARGIN;
+    protected Duration expirationMargin = DEFAULT_EXPIRATION_MARGIN;
 
     protected Builder() {}
 

oauth2_http/javatests/com/google/auth/oauth2/DefaultCredentialsProviderTest.java

@@ -470,6 +470,34 @@ public void getDefaultCredentials_quota_project() throws IOException {
     testUserProvidesToken(testProvider, USER_CLIENT_ID, USER_CLIENT_SECRET, REFRESH_TOKEN);
   }
 
+  @Test
+  public void getDefaultCredentials_compute_quotaProject() throws IOException {
+    MockMetadataServerTransportFactory transportFactory = new MockMetadataServerTransportFactory();
+    transportFactory.transport.setAccessToken(ACCESS_TOKEN);
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    testProvider.setEnv(
+        DefaultCredentialsProvider.QUOTA_PROJECT_ENV_VAR, QUOTA_PROJECT_FROM_ENVIRONMENT);
+
+    GoogleCredentials defaultCredentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertTrue(defaultCredentials instanceof ComputeEngineCredentials);
+    assertEquals(QUOTA_PROJECT_FROM_ENVIRONMENT, defaultCredentials.getQuotaProjectId());
+  }
+
+  @Test
+  public void getDefaultCredentials_cloudshell_quotaProject() throws IOException {
+    MockHttpTransportFactory transportFactory = new MockHttpTransportFactory();
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    testProvider.setEnv(DefaultCredentialsProvider.CLOUD_SHELL_ENV_VAR, "4");
+    testProvider.setEnv(
+        DefaultCredentialsProvider.QUOTA_PROJECT_ENV_VAR, QUOTA_PROJECT_FROM_ENVIRONMENT);
+
+    GoogleCredentials defaultCredentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertTrue(defaultCredentials instanceof CloudShellCredentials);
+    assertEquals(QUOTA_PROJECT_FROM_ENVIRONMENT, defaultCredentials.getQuotaProjectId());
+  }
+
   @Test
   public void getDefaultCredentials_envNoGceCheck_noGceRequest() throws IOException {
     MockRequestCountingTransportFactory transportFactory =