fix(uiautomator2-server): enumerate class regex matches with regression coverage

packages/uiautomator2-server/app/src/androidTestE2eTest/java/io/appium/uiautomator2/unittest/test/ClassRegexCommandsTest.java

@@ -0,0 +1,99 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.appium.uiautomator2.unittest.test;
+
+import android.content.Context;
+import android.content.Intent;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import io.appium.uiautomator2.model.By;
+import io.appium.uiautomator2.unittest.fixture.ClassRegexActivity;
+import io.appium.uiautomator2.unittest.test.internal.BaseTest;
+import io.appium.uiautomator2.unittest.test.internal.Response;
+
+import static io.appium.uiautomator2.unittest.test.internal.TestUtils.extractElementId;
+import static io.appium.uiautomator2.unittest.test.internal.TestUtils.waitForElement;
+import static io.appium.uiautomator2.unittest.test.internal.commands.DeviceCommands.findElements;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+public class ClassRegexCommandsTest extends BaseTest {
+    @Before
+    @Override
+    public void launchAUT() throws JSONException {
+        Context context = InstrumentationRegistry.getInstrumentation().getTargetContext();
+        context.startActivity(new Intent(context, ClassRegexActivity.class)
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK));
+        assertTrue(waitForElement(By.accessibilityId("regex-button-1")).isSuccessful());
+    }
+
+    @Test
+    public void findsMatchesAtTheSameIndexUnderDifferentParents() throws JSONException {
+        // Both labels have index 0, so enumerating index(0), index(1), ... loses one.
+        assertRegexMatchesExactClass("android.widget.TextView");
+    }
+
+    @Test
+    public void findsMatchesWhenNoMatchHasIndexZero() throws JSONException {
+        // Both buttons have index 1, so index(0) stops the old enumeration immediately.
+        assertRegexMatchesExactClass("android.widget.Button");
+    }
+
+    @Test
+    public void preservesExplicitInstance() throws JSONException {
+        for (int i = 0; i < 2; i++) {
+            Set<String> expected = elementIds(By.accessibilityId("regex-button-" + i));
+            assertEquals(1, expected.size());
+            assertEquals(expected, elementIds(By.androidUiAutomator(
+                    selector("android.widget.Button", true) + ".instance(" + i + ")")));
+        }
+    }
+
+    private void assertRegexMatchesExactClass(String className) throws JSONException {
+        Set<String> expected = elementIds(By.androidUiAutomator(selector(className, false)));
+        assertEquals("The fixture must expose two distinct matching elements", 2, expected.size());
+        assertEquals(expected, elementIds(By.androidUiAutomator(selector(className, true))));
+    }
+
+    private String selector(String className, boolean regex) {
+        return "new UiSelector().packageName(\"io.appium.uiautomator2.e2etest\")."
+                + (regex ? "classNameMatches" : "className")
+                + "(\"" + (regex ? className.replace(".", "[.]") : className) + "\")";
+    }
+
+    private Set<String> elementIds(By by) throws JSONException {
+        Response response = findElements(by);
+        assertTrue(by + " should succeed", response.isSuccessful());
+        JSONArray elements = response.getValue();
+        Set<String> result = new HashSet<>();
+        for (int i = 0; i < elements.length(); i++) {
+            String id = extractElementId(elements.getJSONObject(i));
+            assertNotNull(id);
+            assertTrue("Duplicate element: " + id, result.add(id));
+        }
+        return result;
+    }
+}

packages/uiautomator2-server/app/src/e2eTest/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application>
+        <activity android:name="io.appium.uiautomator2.unittest.fixture.ClassRegexActivity"
+                  android:exported="false"
+                  android:theme="@android:style/Theme.Material.Light.NoActionBar" />
+    </application>
+</manifest>

packages/uiautomator2-server/app/src/e2eTest/java/io/appium/uiautomator2/unittest/fixture/ClassRegexActivity.java

@@ -0,0 +1,49 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.appium.uiautomator2.unittest.fixture;
+
+import android.annotation.SuppressLint;
+import android.app.Activity;
+import android.os.Bundle;
+import android.widget.Button;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+/** A fixed hierarchy for testing regex selectors across different parents. */
+public class ClassRegexActivity extends Activity {
+    // Fixed strings are intentional: this screen is only a test fixture.
+    @SuppressLint("SetTextI18n")
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        LinearLayout root = new LinearLayout(this);
+        root.setOrientation(LinearLayout.VERTICAL);
+        for (int i = 0; i < 2; i++) {
+            LinearLayout row = new LinearLayout(this);
+            row.setOrientation(LinearLayout.VERTICAL);
+            TextView label = new TextView(this);
+            label.setText("Label " + i);
+            label.setContentDescription("regex-label-" + i);
+            row.addView(label);
+            Button button = new Button(this);
+            button.setText("Button " + i);
+            button.setContentDescription("regex-button-" + i);
+            row.addView(button);
+            root.addView(row);
+        }
+        setContentView(root);
+    }
+}

packages/uiautomator2-server/app/src/main/java/io/appium/uiautomator2/utils/ByUiAutomatorFinder.java

@@ -99,21 +99,17 @@ public static List<AccessibleUiObject> matchDescendantElements(UiSelector sel,
                     : Collections.singletonList(instanceObj);
         }
 
-        final boolean useIndex = doesUiSelectorHaveAttribute(sel, "CLASS_REGEX");
-        if (useIndex) {
-            Logger.debug("Selector has CLASS_REGEX attribute");
-        }
         final List<AccessibleUiObject> elements = new ArrayList<>();
         int descendantIndex = 0;
         do {
             AccessibleUiObject lastFoundObj;
+            UiSelector tmpSelector = sel.instance(descendantIndex);
+            Logger.debug(String.format("matchDescendantElements temporary selector: %s", tmpSelector));
             if (context == null) {
-                UiSelector tmpSelector = useIndex ? sel.index(descendantIndex) : sel.instance(descendantIndex);
-                Logger.debug(String.format("matchDescendantElements temporary selector: %s", tmpSelector));
                 lastFoundObj = toAccessibleUiObject(getUiDevice().findObject(tmpSelector));
             } else {
                 try {
-                    lastFoundObj = context.getChild(sel.instance(descendantIndex));
+                    lastFoundObj = context.getChild(tmpSelector);
                 } catch (UiObjectNotFoundException e) {
                     lastFoundObj = null;
                 }

packages/uiautomator2-server/scripts/e2e.sh

@@ -7,7 +7,7 @@ adb shell settings put global hidden_api_policy_p_apps 1
 # bottom edge then becomes the system home gesture, which breaks scroll tests in landscape.
 adb shell cmd overlay enable com.android.internal.systemui.navbar.threebutton || true
 
-classes=(AlertCommandsTest ActionsCommandsTest ElementCommandsTest DeviceCommandsTest)
+classes=(AlertCommandsTest ActionsCommandsTest ElementCommandsTest DeviceCommandsTest ClassRegexCommandsTest)
 did_fail=0
 for cls_name in "${classes[@]}"; do
   if ! ./gradlew connectedE2eTestDebugAndroidTest -Pandroid.testInstrumentationRunnerArguments.class=io.appium.uiautomator2.unittest.test.$cls_name; then