Skylint: check for bad operations

So far, only checks for usages of '+' on dictionary literals and
comprehensions.

RELNOTES: none
PiperOrigin-RevId: 170336917

1 files changed, 66 insertions, 0 deletions

diff --git a/src/tools/skylark/java/com/google/devtools/skylark/skylint/BadOperationChecker.java b/src/tools/skylark/java/com/google/devtools/skylark/skylint/BadOperationChecker.java
new file mode 100644
index 0000000000..8b08bdff65
--- /dev/null
+++ b/src/tools/skylark/java/com/google/devtools/skylark/skylint/BadOperationChecker.java
@@ -0,0 +1,66 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// 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.google.devtools.skylark.skylint;
+
+import com.google.devtools.build.lib.syntax.AugmentedAssignmentStatement;
+import com.google.devtools.build.lib.syntax.BinaryOperatorExpression;
+import com.google.devtools.build.lib.syntax.BuildFileAST;
+import com.google.devtools.build.lib.syntax.DictComprehension;
+import com.google.devtools.build.lib.syntax.DictionaryLiteral;
+import com.google.devtools.build.lib.syntax.Operator;
+import com.google.devtools.build.lib.syntax.SyntaxTreeVisitor;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Checks for operations that are deprecated */
+public class BadOperationChecker extends SyntaxTreeVisitor {
+  private final List<Issue> issues = new ArrayList<>();
+
+  private BadOperationChecker() {}
+
+  public static List<Issue> check(BuildFileAST ast) {
+    BadOperationChecker checker = new BadOperationChecker();
+    checker.visit(ast);
+    return checker.issues;
+  }
+
+  @Override
+  public void visit(BinaryOperatorExpression node) {
+    super.visit(node);
+    if (node.getOperator() == Operator.PLUS) {
+      if (node.getLhs() instanceof DictionaryLiteral
+          || node.getLhs() instanceof DictComprehension
+          || node.getRhs() instanceof DictionaryLiteral
+          || node.getRhs() instanceof DictComprehension) {
+        issues.add(
+            new Issue(
+                "'+' operator is deprecated and should not be used on dictionaries",
+                node.getLocation()));
+      }
+    }
+  }
+
+  @Override
+  public void visit(AugmentedAssignmentStatement node) {
+    super.visit(node);
+    if (node.getExpression() instanceof DictionaryLiteral
+        || node.getExpression() instanceof DictComprehension) {
+      issues.add(
+          new Issue(
+              "'+' operator is deprecated and should not be used on dictionaries",
+              node.getLocation()));
+    }
+  }
+}