Fix shadowed variables in various places - part 1 (#77555)

Part of #19752.

Fix a number of locations where local variables or parameters are shadowing a field
that is defined in the same class.

build-tools-internal/src/main/resources/checkstyle.xml

@@ -95,6 +95,17 @@
       lines up with the directory structure. -->
     <module name="PackageDeclaration" />
 
+    <!-- Checks that a local variable or a parameter does not shadow a field that is defined in the same class. -->
+    <!-- Disabled until existing violations are fixed -->
+    <!--
+    <module name="HiddenField">
+        <property name="ignoreConstructorParameter" value="true" />
+        <property name="ignoreSetter" value="true" />
+        <property name="setterCanReturnItsClass" value="true"/>
+        <property name="ignoreFormat" value="^(threadPool)$"/>
+    </module>
+    -->
+
     <!-- We don't use Java's builtin serialization and we suppress all warning
       about it. The flip side of that coin is that we shouldn't _try_ to use
       it. We can't outright ban it with ForbiddenApis because it complain about

client/benchmark/src/main/java/org/elasticsearch/client/benchmark/ops/search/SearchBenchmarkTask.java

@@ -32,8 +32,8 @@ public SearchBenchmarkTask(SearchRequestExecutor searchRequestExecutor, String b
     }
 
     @Override
-    public void setUp(SampleRecorder sampleRecorder) throws Exception {
-        this.sampleRecorder = sampleRecorder;
+    public void setUp(SampleRecorder recorder) throws Exception {
+        this.sampleRecorder = recorder;
     }
 
     @Override

client/rest/src/main/java/org/elasticsearch/client/HeapBufferedAsyncResponseConsumer.java

@@ -65,8 +65,8 @@ public int getBufferLimit() {
     }
 
     @Override
-    protected void onResponseReceived(HttpResponse response) throws HttpException, IOException {
-        this.response = response;
+    protected void onResponseReceived(HttpResponse httpResponse) throws HttpException, IOException {
+        this.response = httpResponse;
     }
 
     @Override

client/rest/src/main/java/org/elasticsearch/client/Request.java

@@ -109,8 +109,8 @@ public void setEntity(HttpEntity entity) {
      * If you need a different content type then use
      * {@link #setEntity(HttpEntity)}.
      */
-    public void setJsonEntity(String entity) {
-        setEntity(entity == null ? null : new NStringEntity(entity, ContentType.APPLICATION_JSON));
+    public void setJsonEntity(String body) {
+        setEntity(body == null ? null : new NStringEntity(body, ContentType.APPLICATION_JSON));
     }
 
     /**

client/rest/src/main/java/org/elasticsearch/client/RestClient.java

@@ -270,10 +270,10 @@ public Response performRequest(Request request) throws IOException {
         return performRequest(nextNodes(), internalRequest, null);
     }
 
-    private Response performRequest(final NodeTuple<Iterator<Node>> nodeTuple,
+    private Response performRequest(final NodeTuple<Iterator<Node>> tuple,
                                     final InternalRequest request,
                                     Exception previousException) throws IOException {
-        RequestContext context = request.createContextForNextAttempt(nodeTuple.nodes.next(), nodeTuple.authCache);
+        RequestContext context = request.createContextForNextAttempt(tuple.nodes.next(), tuple.authCache);
         HttpResponse httpResponse;
         try {
             httpResponse = client.execute(context.requestProducer, context.asyncResponseConsumer, context.context, null).get();
@@ -282,8 +282,8 @@ private Response performRequest(final NodeTuple<Iterator<Node>> nodeTuple,
             onFailure(context.node);
             Exception cause = extractAndWrapCause(e);
             addSuppressedException(previousException, cause);
-            if (nodeTuple.nodes.hasNext()) {
-                return performRequest(nodeTuple, request, cause);
+            if (tuple.nodes.hasNext()) {
+                return performRequest(tuple, request, cause);
             }
             if (cause instanceof IOException) {
                 throw (IOException) cause;
@@ -298,8 +298,8 @@ private Response performRequest(final NodeTuple<Iterator<Node>> nodeTuple,
             return responseOrResponseException.response;
         }
         addSuppressedException(previousException, responseOrResponseException.responseException);
-        if (nodeTuple.nodes.hasNext()) {
-            return performRequest(nodeTuple, request, responseOrResponseException.responseException);
+        if (tuple.nodes.hasNext()) {
+            return performRequest(tuple, request, responseOrResponseException.responseException);
         }
         throw responseOrResponseException.responseException;
     }
@@ -362,11 +362,11 @@ public Cancellable performRequestAsync(Request request, ResponseListener respons
         }
     }
 
-    private void performRequestAsync(final NodeTuple<Iterator<Node>> nodeTuple,
+    private void performRequestAsync(final NodeTuple<Iterator<Node>> tuple,
                                      final InternalRequest request,
                                      final FailureTrackingResponseListener listener) {
         request.cancellable.runIfNotCancelled(() -> {
-            final RequestContext context = request.createContextForNextAttempt(nodeTuple.nodes.next(), nodeTuple.authCache);
+            final RequestContext context = request.createContextForNextAttempt(tuple.nodes.next(), tuple.authCache);
             client.execute(context.requestProducer, context.asyncResponseConsumer, context.context, new FutureCallback<HttpResponse>() {
                 @Override
                 public void completed(HttpResponse httpResponse) {
@@ -375,9 +375,9 @@ public void completed(HttpResponse httpResponse) {
                         if (responseOrResponseException.responseException == null) {
                             listener.onSuccess(responseOrResponseException.response);
                         } else {
-                            if (nodeTuple.nodes.hasNext()) {
+                            if (tuple.nodes.hasNext()) {
                                 listener.trackFailure(responseOrResponseException.responseException);
-                                performRequestAsync(nodeTuple, request, listener);
+                                performRequestAsync(tuple, request, listener);
                             } else {
                                 listener.onDefinitiveFailure(responseOrResponseException.responseException);
                             }
@@ -392,9 +392,9 @@ public void failed(Exception failure) {
                     try {
                         RequestLogger.logFailedRequest(logger, request.httpRequest, context.node, failure);
                         onFailure(context.node);
-                        if (nodeTuple.nodes.hasNext()) {
+                        if (tuple.nodes.hasNext()) {
                             listener.trackFailure(failure);
-                            performRequestAsync(nodeTuple, request, listener);
+                            performRequestAsync(tuple, request, listener);
                         } else {
                             listener.onDefinitiveFailure(failure);
                         }
@@ -421,9 +421,9 @@ public void cancelled() {
      * @throws IOException if no nodes are available
      */
     private NodeTuple<Iterator<Node>> nextNodes() throws IOException {
-        NodeTuple<List<Node>> nodeTuple = this.nodeTuple;
-        Iterable<Node> hosts = selectNodes(nodeTuple, blacklist, lastNodeIndex, nodeSelector);
-        return new NodeTuple<>(hosts.iterator(), nodeTuple.authCache);
+        NodeTuple<List<Node>> tuple = this.nodeTuple;
+        Iterable<Node> hosts = selectNodes(tuple, blacklist, lastNodeIndex, nodeSelector);
+        return new NodeTuple<>(hosts.iterator(), tuple.authCache);
     }
 
     /**
@@ -639,17 +639,17 @@ void onSuccess(Response response) {
         /**
          * Tracks one last definitive failure and returns to the caller by notifying the wrapped listener
          */
-        void onDefinitiveFailure(Exception exception) {
-            trackFailure(exception);
+        void onDefinitiveFailure(Exception e) {
+            trackFailure(e);
             responseListener.onFailure(this.exception);
         }
 
         /**
          * Tracks an exception, which caused a retry hence we should not return yet to the caller
          */
-        void trackFailure(Exception exception) {
-            addSuppressedException(this.exception, exception);
-            this.exception = exception;
+        void trackFailure(Exception e) {
+            addSuppressedException(this.exception, e);
+            this.exception = e;
         }
     }
 
@@ -752,26 +752,26 @@ private class InternalRequest {
                 RestClient.this.warningsHandler : request.getOptions().getWarningsHandler();
         }
 
-        private void setHeaders(HttpRequest httpRequest, Collection<Header> requestHeaders) {
+        private void setHeaders(HttpRequest req, Collection<Header> requestHeaders) {
             // request headers override default headers, so we don't add default headers if they exist as request headers
             final Set<String> requestNames = new HashSet<>(requestHeaders.size());
             for (Header requestHeader : requestHeaders) {
-                httpRequest.addHeader(requestHeader);
+                req.addHeader(requestHeader);
                 requestNames.add(requestHeader.getName());
             }
             for (Header defaultHeader : defaultHeaders) {
                 if (requestNames.contains(defaultHeader.getName()) == false) {
-                    httpRequest.addHeader(defaultHeader);
+                    req.addHeader(defaultHeader);
                 }
             }
             if (compressionEnabled) {
-                httpRequest.addHeader("Accept-Encoding", "gzip");
+                req.addHeader("Accept-Encoding", "gzip");
             }
         }
 
-        private void setRequestConfig(HttpRequestBase httpRequest, RequestConfig requestConfig) {
+        private void setRequestConfig(HttpRequestBase requestBase, RequestConfig requestConfig) {
             if (requestConfig != null) {
-                httpRequest.setConfig(requestConfig);
+                requestBase.setConfig(requestConfig);
             }
         }
 

client/rest/src/test/java/org/elasticsearch/client/FailureTrackingResponseListenerTests.java

@@ -43,8 +43,8 @@ public void testOnSuccess() {
 
         final Response response = mockResponse();
         listener.onSuccess(response);
-        assertSame(response, responseListener.response.get());
-        assertNull(responseListener.exception.get());
+        assertSame(response, responseListener.lastResponse.get());
+        assertNull(responseListener.lastException.get());
     }
 
     public void testOnFailure() {
@@ -56,20 +56,20 @@ public void testOnFailure() {
             RuntimeException runtimeException = new RuntimeException("test" + i);
             expectedExceptions[i] = runtimeException;
             listener.trackFailure(runtimeException);
-            assertNull(responseListener.response.get());
-            assertNull(responseListener.exception.get());
+            assertNull(responseListener.lastResponse.get());
+            assertNull(responseListener.lastException.get());
         }
 
         if (randomBoolean()) {
             Response response = mockResponse();
             listener.onSuccess(response);
-            assertSame(response, responseListener.response.get());
-            assertNull(responseListener.exception.get());
+            assertSame(response, responseListener.lastResponse.get());
+            assertNull(responseListener.lastException.get());
         } else {
             RuntimeException runtimeException = new RuntimeException("definitive");
             listener.onDefinitiveFailure(runtimeException);
-            assertNull(responseListener.response.get());
-            Throwable exception = responseListener.exception.get();
+            assertNull(responseListener.lastResponse.get());
+            Throwable exception = responseListener.lastException.get();
             assertSame(runtimeException, exception);
 
             int i = numIters - 1;
@@ -83,19 +83,19 @@ public void testOnFailure() {
     }
 
     private static class MockResponseListener implements ResponseListener {
-        private final AtomicReference<Response> response = new AtomicReference<>();
-        private final AtomicReference<Exception> exception = new AtomicReference<>();
+        private final AtomicReference<Response> lastResponse = new AtomicReference<>();
+        private final AtomicReference<Exception> lastException = new AtomicReference<>();
 
         @Override
         public void onSuccess(Response response) {
-            if (this.response.compareAndSet(null, response) == false) {
+            if (this.lastResponse.compareAndSet(null, response) == false) {
                 throw new IllegalStateException("onSuccess was called multiple times");
             }
         }
 
         @Override
         public void onFailure(Exception exception) {
-            if (this.exception.compareAndSet(null, exception) == false) {
+            if (this.lastException.compareAndSet(null, exception) == false) {
                 throw new IllegalStateException("onFailure was called multiple times");
             }
         }

client/rest/src/test/java/org/elasticsearch/client/HostsTrackingFailureListener.java

@@ -33,11 +33,11 @@
  * {@link RestClient.FailureListener} impl that allows to track when it gets called for which host.
  */
 class HostsTrackingFailureListener extends RestClient.FailureListener {
-    private volatile Set<HttpHost> hosts = new HashSet<>();
+    private volatile Set<HttpHost> httpHosts = new HashSet<>();
 
     @Override
     public void onFailure(Node node) {
-        hosts.add(node.getHost());
+        httpHosts.add(node.getHost());
     }
 
     void assertCalled(List<Node> nodes) {
@@ -49,12 +49,12 @@ void assertCalled(List<Node> nodes) {
     }
 
     void assertCalled(HttpHost... hosts) {
-        assertEquals(hosts.length, this.hosts.size());
-        assertThat(this.hosts, containsInAnyOrder(hosts));
-        this.hosts.clear();
+        assertEquals(hosts.length, this.httpHosts.size());
+        assertThat(this.httpHosts, containsInAnyOrder(hosts));
+        this.httpHosts.clear();
     }
 
     void assertNotCalled() {
-        assertEquals(0, hosts.size());
+        assertEquals(0, httpHosts.size());
     }
 }

client/rest/src/test/java/org/elasticsearch/client/RestClientSingleHostIntegTests.java

@@ -95,15 +95,15 @@ public void startHttpServer() throws Exception {
     }
 
     private HttpServer createHttpServer() throws Exception {
-        HttpServer httpServer = MockHttpServer.createHttp(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
-        httpServer.start();
+        HttpServer mockServer = MockHttpServer.createHttp(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        mockServer.start();
         //returns a different status code depending on the path
         for (int statusCode : getAllStatusCodes()) {
-            httpServer.createContext(pathPrefix + "/" + statusCode, new ResponseHandler(statusCode));
+            mockServer.createContext(pathPrefix + "/" + statusCode, new ResponseHandler(statusCode));
         }
         waitForCancelHandler = new WaitForCancelHandler();
-        httpServer.createContext(pathPrefix + "/wait", waitForCancelHandler);
-        return httpServer;
+        mockServer.createContext(pathPrefix + "/wait", waitForCancelHandler);
+        return mockServer;
     }
 
     private static class WaitForCancelHandler implements HttpHandler {
@@ -540,12 +540,12 @@ private Response bodyTest(final String method) throws Exception {
         return bodyTest(restClient, method);
     }
 
-    private Response bodyTest(final RestClient restClient, final String method) throws Exception {
+    private Response bodyTest(final RestClient client, final String method) throws Exception {
         int statusCode = randomStatusCode(getRandom());
-        return bodyTest(restClient, method, statusCode, new Header[0]);
+        return bodyTest(client, method, statusCode, new Header[0]);
     }
 
-    private Response bodyTest(RestClient restClient, String method, int statusCode, Header[] headers) throws Exception {
+    private Response bodyTest(RestClient client, String method, int statusCode, Header[] headers) throws Exception {
         String requestBody = "{ \"field\": \"value\" }";
         Request request = new Request(method, "/" + statusCode);
         request.setJsonEntity(requestBody);
@@ -556,7 +556,7 @@ private Response bodyTest(RestClient restClient, String method, int statusCode,
         request.setOptions(options);
         Response esResponse;
         try {
-            esResponse = RestClientSingleHostTests.performRequestSyncOrAsync(restClient, request);
+            esResponse = RestClientSingleHostTests.performRequestSyncOrAsync(client, request);
         } catch(ResponseException e) {
             esResponse = e.getResponse();
         }

libs/cli/src/main/java/org/elasticsearch/cli/Terminal.java

@@ -49,7 +49,7 @@ public enum Verbosity {
     }
 
     /** The current verbosity for the terminal, defaulting to {@link Verbosity#NORMAL}. */
-    private Verbosity verbosity = Verbosity.NORMAL;
+    private Verbosity currentVerbosity = Verbosity.NORMAL;
 
     /** The newline used when calling println. */
     private final String lineSeparator;
@@ -60,7 +60,7 @@ protected Terminal(String lineSeparator) {
 
     /** Sets the verbosity of the terminal. */
     public void setVerbosity(Verbosity verbosity) {
-        this.verbosity = verbosity;
+        this.currentVerbosity = verbosity;
     }
 
     /** Reads clear text from the terminal input. See {@link Console#readLine()}. */
@@ -128,7 +128,7 @@ public final void errorPrintln(Verbosity verbosity, String msg) {
 
     /** Checks if is enough {@code verbosity} level to be printed */
     public final boolean isPrintable(Verbosity verbosity) {
-        return this.verbosity.ordinal() >= verbosity.ordinal();
+        return this.currentVerbosity.ordinal() >= verbosity.ordinal();
     }
 
     /**

libs/core/src/main/java/org/elasticsearch/core/internal/io/Streams.java

@@ -22,7 +22,7 @@
  */
 public class Streams {
 
-    private static final ThreadLocal<byte[]> buffer = ThreadLocal.withInitial(() -> new byte[8 * 1024]);
+    private static final ThreadLocal<byte[]> LOCAL_BUFFER = ThreadLocal.withInitial(() -> new byte[8 * 1024]);
 
     private Streams() {
 
@@ -63,7 +63,7 @@ public static long copy(final InputStream in, final OutputStream out, byte[] buf
      * @see #copy(InputStream, OutputStream, byte[], boolean)
      */
     public static long copy(final InputStream in, final OutputStream out, boolean close) throws IOException {
-        return copy(in, out, buffer.get(), close);
+        return copy(in, out, LOCAL_BUFFER.get(), close);
     }
 
     /**
@@ -77,6 +77,6 @@ public static long copy(final InputStream in, final OutputStream out, byte[] buf
      * @see #copy(InputStream, OutputStream, byte[], boolean)
      */
     public static long copy(final InputStream in, final OutputStream out) throws IOException {
-        return copy(in, out, buffer.get(), true);
+        return copy(in, out, LOCAL_BUFFER.get(), true);
     }
 }