Add lint check for cut & paste errors in findViewById calls

Change-Id: Ie8ff6629a3e787587516f6fa88c70dfdb7a92d0d

8 files changed, 428 insertions, 37 deletions

diff --git a/lint/libs/lint_api/src/com/android/tools/lint/detector/api/JavaContext.java b/lint/libs/lint_api/src/com/android/tools/lint/detector/api/JavaContext.java
index ae86568..d91f423 100644
--- a/lint/libs/lint_api/src/com/android/tools/lint/detector/api/JavaContext.java
+++ b/lint/libs/lint_api/src/com/android/tools/lint/detector/api/JavaContext.java
@@ -23,6 +23,8 @@ import com.android.tools.lint.client.api.LintDriver;
 
 import java.io.File;
 
+import lombok.ast.ConstructorDeclaration;
+import lombok.ast.MethodDeclaration;
 import lombok.ast.Node;
 
 /**
@@ -105,4 +107,21 @@ public class JavaContext extends Context {
         }
         super.report(issue, location, message, data);
     }
+
+
+    @Nullable
+    public static Node findSurroundingMethod(Node scope) {
+        while (scope != null) {
+            Class<? extends Node> type = scope.getClass();
+            // The Lombok AST uses a flat hierarchy of node type implementation classes
+            // so no need to do instanceof stuff here.
+            if (type == MethodDeclaration.class || type == ConstructorDeclaration.class) {
+                return scope;
+            }
+
+            scope = scope.getParent();
+        }
+
+        return null;
+    }
 }
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 a211029..a475ac6 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
@@ -55,7 +55,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
     private static final List<Issue> sIssues;
 
     static {
-        final int initialCapacity = 129;
+        final int initialCapacity = 130;
         List<Issue> issues = new ArrayList<Issue>(initialCapacity);
 
         issues.add(AccessibilityDetector.ISSUE);
@@ -182,6 +182,7 @@ public class BuiltinIssueRegistry extends IssueRegistry {
         issues.add(SetJavaScriptEnabledDetector.ISSUE);
         issues.add(ToastDetector.ISSUE);
         issues.add(SharedPrefsDetector.ISSUE);
+        issues.add(CutPasteDetector.ISSUE);
         issues.add(NonInternationalizedSmsDetector.ISSUE);
         issues.add(PrivateKeyDetector.ISSUE);
         issues.add(AnnotationDetector.ISSUE);
diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/CutPasteDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/CutPasteDetector.java
new file mode 100644
index 0000000..193ab8f
--- /dev/null
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/CutPasteDetector.java
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2012 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.SdkConstants.RESOURCE_CLZ_ID;
+
+import com.android.annotations.NonNull;
+import com.android.annotations.Nullable;
+import com.android.tools.lint.detector.api.Category;
+import com.android.tools.lint.detector.api.Context;
+import com.android.tools.lint.detector.api.Detector;
+import com.android.tools.lint.detector.api.Issue;
+import com.android.tools.lint.detector.api.JavaContext;
+import com.android.tools.lint.detector.api.Location;
+import com.android.tools.lint.detector.api.Scope;
+import com.android.tools.lint.detector.api.Severity;
+import com.google.common.collect.Maps;
+
+import java.io.File;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import lombok.ast.ArrayAccess;
+import lombok.ast.AstVisitor;
+import lombok.ast.BinaryExpression;
+import lombok.ast.Cast;
+import lombok.ast.Expression;
+import lombok.ast.ForwardingAstVisitor;
+import lombok.ast.If;
+import lombok.ast.MethodInvocation;
+import lombok.ast.Node;
+import lombok.ast.Select;
+import lombok.ast.Statement;
+import lombok.ast.VariableDefinitionEntry;
+import lombok.ast.VariableReference;
+
+/**
+ * Detector looking for cut & paste issues
+ */
+public class CutPasteDetector extends Detector implements Detector.JavaScanner {
+    /** The main issue discovered by this detector */
+    public static final Issue ISSUE = Issue.create(
+            "CutPasteId", //$NON-NLS-1$
+            "Looks for code cut & paste mistakes in findViewbyId() calls",
+
+            "This lint check looks for cases where you have cut & pasted calls to " +
+            "`findViewById` but have forgotten to update the R.id field. It's possible " +
+            "that your code is simply (redundantly) looking up the field repeatedly, " +
+            "but lint cannot distinguish that from a case where you for example want to " +
+            "initialize fields `prev` and `next` and you cut & pasted `findViewById(R.id.prev)` " +
+            "and forgot to update the second initialization to `R.id.next`.",
+
+            Category.CORRECTNESS,
+            6,
+            Severity.WARNING,
+            CutPasteDetector.class,
+            Scope.JAVA_FILE_SCOPE);
+
+    private Node mLastMethod;
+    private Map<String, MethodInvocation> mIds;
+    private Map<String, String> mLhs;
+    private Map<String, String> mCallOperands;
+
+    /** Constructs a new {@link CutPasteDetector} check */
+    public CutPasteDetector() {
+    }
+
+    @Override
+    public boolean appliesTo(@NonNull Context context, @NonNull File file) {
+        return true;
+    }
+
+    // ---- Implements JavaScanner ----
+
+    @Override
+    public List<String> getApplicableMethodNames() {
+        return Collections.singletonList("findViewById"); //$NON-NLS-1$
+    }
+
+    @Override
+    public void visitMethod(@NonNull JavaContext context, @Nullable AstVisitor visitor,
+            @NonNull MethodInvocation call) {
+        String lhs = getLhs(call);
+        if (lhs == null) {
+            return;
+        }
+
+        Node method = JavaContext.findSurroundingMethod(call);
+        if (method == null) {
+            return;
+        } else if (method != mLastMethod) {
+            mIds = Maps.newHashMap();
+            mLhs = Maps.newHashMap();
+            mCallOperands = Maps.newHashMap();
+            mLastMethod = method;
+        }
+
+        String callOperand = call.astOperand() != null ? call.astOperand().toString() : "";
+
+        Expression first = call.astArguments().first();
+        if (first instanceof Select) {
+            Select select = (Select) first;
+            String id = select.astIdentifier().astValue();
+            Expression operand = select.astOperand();
+            if (operand instanceof Select) {
+                Select type = (Select) operand;
+                if (type.astIdentifier().astValue().equals(RESOURCE_CLZ_ID)) {
+                    if (mIds.containsKey(id)) {
+                        if (lhs.equals(mLhs.get(id))) {
+                            return;
+                        }
+                        if (!callOperand.equals(mCallOperands.get(id))) {
+                            return;
+                        }
+                        MethodInvocation earlierCall = mIds.get(id);
+                        if (!isReachableFrom(method, earlierCall, call)) {
+                            return;
+                        }
+                        Location location = context.getLocation(call);
+                        Location secondary = context.getLocation(earlierCall);
+                        secondary.setMessage("First usage here");
+                        location.setSecondary(secondary);
+                        context.report(ISSUE, call, location, String.format(
+                            "The id %1$s has already been looked up in this method; possible " +
+                            "cut & paste error?", first.toString()), null);
+                    } else {
+                        mIds.put(id, call);
+                        mLhs.put(id, lhs);
+                        mCallOperands.put(id, callOperand);
+                    }
+                }
+            }
+        }
+    }
+
+    @Nullable
+    private static String getLhs(@NonNull MethodInvocation call) {
+        Node parent = call.getParent();
+        if (parent instanceof Cast) {
+            parent = parent.getParent();
+        }
+
+        if (parent instanceof VariableDefinitionEntry) {
+            VariableDefinitionEntry vde = (VariableDefinitionEntry) parent;
+            return vde.astName().astValue();
+        } else if (parent instanceof BinaryExpression) {
+            BinaryExpression be = (BinaryExpression) parent;
+            Expression left = be.astLeft();
+            if (left instanceof VariableReference || left instanceof Select) {
+                return be.astLeft().toString();
+            } else if (left instanceof ArrayAccess) {
+                ArrayAccess aa = (ArrayAccess) left;
+                return aa.astOperand().toString();
+            }
+        }
+
+        return null;
+    }
+
+    private static boolean isReachableFrom(
+            @NonNull Node method,
+            @NonNull MethodInvocation from,
+            @NonNull MethodInvocation to) {
+        ReachableVisitor visitor = new ReachableVisitor(from, to);
+        method.accept(visitor);
+
+        return visitor.isReachable();
+    }
+
+    private static class ReachableVisitor extends ForwardingAstVisitor {
+        private final @NonNull MethodInvocation mFrom;
+        private final @NonNull MethodInvocation mTo;
+        private boolean mReachable;
+        private boolean mSeenEnd;
+
+        public ReachableVisitor(@NonNull MethodInvocation from, @NonNull MethodInvocation to) {
+            mFrom = from;
+            mTo = to;
+        }
+
+        boolean isReachable() {
+            return mReachable;
+        }
+
+        @Override
+        public boolean visitMethodInvocation(MethodInvocation node) {
+            if (node == mFrom) {
+                mReachable = true;
+            } else if (node == mTo) {
+                mSeenEnd = true;
+
+            }
+            return super.visitMethodInvocation(node);
+        }
+
+        @Override
+        public boolean visitIf(If node) {
+            Expression condition = node.astCondition();
+            Statement body = node.astStatement();
+            Statement elseBody = node.astElseStatement();
+            if (condition != null) {
+                condition.accept(this);
+            }
+            if (body != null) {
+                boolean wasReachable = mReachable;
+                body.accept(this);
+                mReachable = wasReachable;
+            }
+            if (elseBody != null) {
+                boolean wasReachable = mReachable;
+                elseBody.accept(this);
+                mReachable = wasReachable;
+            }
+
+            endVisit(node);
+
+            return false;
+        }
+
+        @Override
+        public boolean visitNode(Node node) {
+            return mSeenEnd;
+        }
+    }
+}
diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/SharedPrefsDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/SharedPrefsDetector.java
index d38b05e..1f432f7 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/SharedPrefsDetector.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/SharedPrefsDetector.java
@@ -81,22 +81,6 @@ public class SharedPrefsDetector extends Detector implements Detector.JavaScanne
     }
 
     @Nullable
-    private static Node findSurroundingMethod(Node scope) {
-        while (scope != null) {
-            Class<? extends Node> type = scope.getClass();
-            // The Lombok AST uses a flat hierarchy of node type implementation classes
-            // so no need to do instanceof stuff here.
-            if (type == MethodDeclaration.class || type == ConstructorDeclaration.class) {
-                return scope;
-            }
-
-            scope = scope.getParent();
-        }
-
-        return null;
-    }
-
-    @Nullable
     private static NormalTypeBody findSurroundingTypeBody(Node scope) {
         while (scope != null) {
             Class<? extends Node> type = scope.getClass();
@@ -156,7 +140,7 @@ public class SharedPrefsDetector extends Detector implements Detector.JavaScanne
             allowCommitBeforeTarget = false;
         }
 
-        Node method = findSurroundingMethod(parent);
+        Node method = JavaContext.findSurroundingMethod(parent);
         if (method == null) {
             return;
         }
diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/ToastDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/ToastDetector.java
index 52ae8ed..e8f8d6e 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/ToastDetector.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/ToastDetector.java
@@ -31,11 +31,9 @@ import java.util.Collections;
 import java.util.List;
 
 import lombok.ast.AstVisitor;
-import lombok.ast.ConstructorDeclaration;
 import lombok.ast.Expression;
 import lombok.ast.ForwardingAstVisitor;
 import lombok.ast.IntegralLiteral;
-import lombok.ast.MethodDeclaration;
 import lombok.ast.MethodInvocation;
 import lombok.ast.Node;
 import lombok.ast.Return;
@@ -75,21 +73,6 @@ public class ToastDetector extends Detector implements Detector.JavaScanner {
         return Collections.singletonList("makeText"); //$NON-NLS-1$
     }
 
-    private Node findSurroundingMethod(Node scope) {
-        while (scope != null) {
-            Class<? extends Node> type = scope.getClass();
-            // The Lombok AST uses a flat hierarchy of node type implementation classes
-            // so no need to do instanceof stuff here.
-            if (type == MethodDeclaration.class || type == ConstructorDeclaration.class) {
-                return scope;
-            }
-
-            scope = scope.getParent();
-        }
-
-        return null;
-    }
-
     @Override
     public void visitMethod(@NonNull JavaContext context, @Nullable AstVisitor visitor,
             @NonNull MethodInvocation node) {
@@ -118,7 +101,7 @@ public class ToastDetector extends Detector implements Detector.JavaScanner {
             }
         }
 
-        Node method = findSurroundingMethod(node.getParent());
+        Node method = JavaContext.findSurroundingMethod(node.getParent());
         if (method == null) {
             return;
         }
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/CutPasteDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/CutPasteDetectorTest.java
new file mode 100644
index 0000000..df02a41
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/CutPasteDetectorTest.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2012 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 CutPasteDetectorTest extends AbstractCheckTest {
+    @Override
+    protected Detector getDetector() {
+        return new CutPasteDetector();
+    }
+
+    public void test() throws Exception {
+        assertEquals(
+            "src/test/pkg/PasteError.java:15: Warning: The id R.id.textView1 has already been looked up in this method; possible cut & paste error? [CutPasteId]\n" +
+            "        View view2 = findViewById(R.id.textView1);\n" +
+            "                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "    src/test/pkg/PasteError.java:14: First usage here\n" +
+            "src/test/pkg/PasteError.java:71: Warning: The id R.id.textView1 has already been looked up in this method; possible cut & paste error? [CutPasteId]\n" +
+            "            view2 = findViewById(R.id.textView1);\n" +
+            "                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "    src/test/pkg/PasteError.java:68: First usage here\n" +
+            "src/test/pkg/PasteError.java:78: Warning: The id R.id.textView1 has already been looked up in this method; possible cut & paste error? [CutPasteId]\n" +
+            "            view2 = findViewById(R.id.textView1);\n" +
+            "                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "    src/test/pkg/PasteError.java:76: First usage here\n" +
+            "src/test/pkg/PasteError.java:86: Warning: The id R.id.textView1 has already been looked up in this method; possible cut & paste error? [CutPasteId]\n" +
+            "            view2 = findViewById(R.id.textView1);\n" +
+            "                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "    src/test/pkg/PasteError.java:83: First usage here\n" +
+            "src/test/pkg/PasteError.java:95: Warning: The id R.id.textView1 has already been looked up in this method; possible cut & paste error? [CutPasteId]\n" +
+            "                view2 = findViewById(R.id.textView1);\n" +
+            "                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+            "    src/test/pkg/PasteError.java:91: First usage here\n" +
+            "0 errors, 5 warnings\n",
+
+            lintProject("src/test/pkg/PasteError.java.txt=>" +
+                    "src/test/pkg/PasteError.java"));
+    }
+}
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/SharedPrefsDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/SharedPrefsDetectorTest.java
index dbfc838..7035c21 100644
--- a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/SharedPrefsDetectorTest.java
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/SharedPrefsDetectorTest.java
@@ -19,7 +19,7 @@ package com.android.tools.lint.checks;
 import com.android.tools.lint.detector.api.Detector;
 
 @SuppressWarnings("javadoc")
-public class SharedPrefsDetectorTest  extends AbstractCheckTest {
+public class SharedPrefsDetectorTest extends AbstractCheckTest {
     @Override
     protected Detector getDetector() {
         return new SharedPrefsDetector();
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/src/test/pkg/PasteError.java.txt b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/src/test/pkg/PasteError.java.txt
new file mode 100644
index 0000000..b12b56b
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/src/test/pkg/PasteError.java.txt
@@ -0,0 +1,109 @@
+package test.pkg;
+
+import android.app.Activity;
+import android.view.View;
+
+public class PasteError extends Activity {
+    protected void ok() {
+        Button button1 = (Button) findViewById(R.id.textView1);
+        mView2 = findViewById(R.id.textView2);
+        View view3 = findViewById(R.id.activity_main);
+    }
+
+    protected void error() {
+        View view1 = findViewById(R.id.textView1);
+        View view2 = findViewById(R.id.textView1);
+        View view3 = findViewById(R.id.textView2);
+    }
+
+    protected void ok2() {
+        View view1;
+        if (true) {
+            view1 = findViewById(R.id.textView1);
+        } else {
+            view1 = findViewById(R.id.textView1);
+        }
+    }
+
+    @SuppressLint("CutPasteId")
+    protected void suppressed() {
+        View view1 = findViewById(R.id.textView1);
+        View view2 = findViewById(R.id.textView1);
+    }
+
+    private void ok3() {
+        if (view == null || view.findViewById(R.id.city_name) == null) {
+            view = mInflater.inflate(R.layout.city_list_item, parent, false);
+        }
+        TextView name = (TextView) view.findViewById(R.id.city_name);
+    }
+
+    private void ok4() {
+        mPrevAlbumWrapper = mPrevTrackLayout.findViewById(R.id.album_wrapper);
+        mNextAlbumWrapper = mNextTrackLayout.findViewById(R.id.album_wrapper);
+    }
+
+    @Override
+    public View getView(int position, View convertView, ViewGroup parent) {
+        View listItem = convertView;
+        if (getItemViewType(position) == VIEW_TYPE_HEADER) {
+            TextView header = (TextView) listItem.findViewById(R.id.name);
+        } else if (getItemViewType(position) == VIEW_TYPE_BOOLEAN) {
+            TextView filterName = (TextView) listItem.findViewById(R.id.name);
+        } else {
+            TextView filterName = (TextView) listItem.findViewById(R.id.name);
+        }
+    }
+
+    protected void ok_branch_1() {
+        if (true) {
+            view1 = findViewById(R.id.textView1);
+        } else {
+            view2 = findViewById(R.id.textView1);
+        }
+    }
+
+    protected void error_branch_1() {
+        if (true) {
+            view1 = findViewById(R.id.textView1);
+        }
+        if (true) {
+            view2 = findViewById(R.id.textView1);
+        }
+    }
+
+    protected void error_branch_2() {
+        view1 = findViewById(R.id.textView1);
+        if (true) {
+            view2 = findViewById(R.id.textView1);
+        }
+    }
+
+    protected void error_branch_3() {
+        view1 = findViewById(R.id.textView1);
+        if (true) {
+        } else {
+            view2 = findViewById(R.id.textView1);
+        }
+    }
+
+    protected void error_branch_4() {
+        view1 = findViewById(R.id.textView1);
+        if (true) {
+        } else {
+            if (true) {
+                view2 = findViewById(R.id.textView1);
+            }
+        }
+    }
+
+    protected void ok_branch_2() {
+        if (true) {
+            view1 = findViewById(R.id.textView1);
+        } else {
+            if (true) {
+                view2 = findViewById(R.id.textView1);
+            }
+        }
+    }
+}