Add new lint rule looking for style definition cycles

This changeset fixes enhancement
23288: Style extending itself Lint rule

Change-Id: Id35bcce02b55735becb2260a3276128bfd71f2a6

4 files changed, 137 insertions, 0 deletions

diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
index cc2a799..689ad89 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/BuiltinIssueRegistry.java
@@ -61,6 +61,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
         issues.add(WrongIdDetector.UNKNOWN_ID);
         issues.add(WrongIdDetector.UNKNOWN_ID_LAYOUT);
         issues.add(StateListDetector.ISSUE);
+        issues.add(StyleCycleDetector.ISSUE);
         issues.add(InefficientWeightDetector.INEFFICIENT_WEIGHT);
         issues.add(InefficientWeightDetector.NESTED_WEIGHTS);
         issues.add(InefficientWeightDetector.BASELINE_WEIGHTS);
diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/StyleCycleDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/StyleCycleDetector.java
new file mode 100644
index 0000000..8c1d6d3
--- /dev/null
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/StyleCycleDetector.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * 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 com.android.tools.lint.checks;
+
+import static com.android.tools.lint.detector.api.LintConstants.ATTR_NAME;
+import static com.android.tools.lint.detector.api.LintConstants.ATTR_PARENT;
+import static com.android.tools.lint.detector.api.LintConstants.STYLE_RESOURCE_PREFIX;
+import static com.android.tools.lint.detector.api.LintConstants.TAG_STYLE;
+
+import com.android.resources.ResourceFolderType;
+import com.android.tools.lint.detector.api.Category;
+import com.android.tools.lint.detector.api.Issue;
+import com.android.tools.lint.detector.api.ResourceXmlDetector;
+import com.android.tools.lint.detector.api.Scope;
+import com.android.tools.lint.detector.api.Severity;
+import com.android.tools.lint.detector.api.Speed;
+import com.android.tools.lint.detector.api.XmlContext;
+
+import org.w3c.dom.Attr;
+import org.w3c.dom.Element;
+
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * Checks for cycles in style definitions
+ */
+public class StyleCycleDetector extends ResourceXmlDetector {
+    /** The main issue discovered by this detector */
+    public static final Issue ISSUE = Issue.create(
+            "StyleCycle", //$NON-NLS-1$
+            "Looks for cycles in style definitions",
+            "There should be no cycles in style definitions as this can lead to runtime " +
+            "exceptions.",
+            Category.CORRECTNESS,
+            8,
+            Severity.ERROR,
+            StyleCycleDetector.class,
+            Scope.RESOURCE_FILE_SCOPE);
+
+    /** Constructs a new {@link StyleCycleDetector} */
+    public StyleCycleDetector() {
+    }
+
+    @Override
+    public boolean appliesTo(ResourceFolderType folderType) {
+        return folderType == ResourceFolderType.VALUES;
+    }
+
+    @Override
+    public Speed getSpeed() {
+        return Speed.FAST;
+    }
+
+    @Override
+    public Collection<String> getApplicableElements() {
+        return Collections.singleton(TAG_STYLE);
+    }
+
+    @Override
+    public void visitElement(XmlContext context, Element element) {
+        Attr parentNode = element.getAttributeNode(ATTR_PARENT);
+        if (parentNode != null) {
+            String parent = parentNode.getValue();
+            String name = element.getAttribute(ATTR_NAME);
+            if (parent.endsWith(name) &&
+                    parent.equals(STYLE_RESOURCE_PREFIX + name)) {
+                context.report(ISSUE, context.getLocation(parentNode),
+                        String.format("Style %1$s should not extend itself", name), null);
+            }
+        }
+    }
+}
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/StyleCycleDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/StyleCycleDetectorTest.java
new file mode 100644
index 0000000..39126df
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/StyleCycleDetectorTest.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * 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 com.android.tools.lint.checks;
+
+import com.android.tools.lint.detector.api.Detector;
+
+@SuppressWarnings("javadoc")
+public class StyleCycleDetectorTest extends AbstractCheckTest {
+    @Override
+    protected Detector getDetector() {
+        return new StyleCycleDetector();
+    }
+
+    public void test() throws Exception {
+        assertEquals(
+            "styles.xml:9: Error: Style DetailsPage_EditorialBuyButton should not extend itself",
+
+            lintProject("res/values/styles.xml"));
+    }
+}
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/styles.xml b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/styles.xml
new file mode 100644
index 0000000..34e2d6f
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/styles.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+
+<style name="DetailsPage_BuyButton" parent="@style/DetailsPage_Button">
+       <item name="android:textColor">@color/buy_button</item>
+       <item name="android:background">@drawable/details_page_buy_button</item>
+</style>
+
+<style name="DetailsPage_EditorialBuyButton" parent="@style/DetailsPage_EditorialBuyButton" />
+<!-- Should have been:
+<style name="DetailsPage_EditorialBuyButton" parent="@style/DetailsPage_BuyButton" />
+-->
+
+</resources>
+