tools: update ESLint, fix unused vars bug

Update ESLint to 3.0.0. This includes an enhancement to `no-unused-vars`
such that it finds a few instances in our code base that it did not find
previously (fixed in previous commits readying this for landing).

PR-URL: https://github.com/nodejs/node/pull/7601
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

1 files changed, 212 insertions, 0 deletions

diff --git a/tools/eslint/lib/rules/no-mixed-operators.js b/tools/eslint/lib/rules/no-mixed-operators.js
new file mode 100644
index 0000000000..9a8b1c3925
--- /dev/null
+++ b/tools/eslint/lib/rules/no-mixed-operators.js
@@ -0,0 +1,212 @@
+/**
+ * @fileoverview Rule to disallow mixed binary operators.
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var astUtils = require("../ast-utils.js");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+var ARITHMETIC_OPERATORS = ["+", "-", "*", "/", "%", "**"];
+var BITWISE_OPERATORS = ["&", "|", "^", "~", "<<", ">>", ">>>"];
+var COMPARISON_OPERATORS = ["==", "!=", "===", "!==", ">", ">=", "<", "<="];
+var LOGICAL_OPERATORS = ["&&", "||"];
+var RELATIONAL_OPERATORS = ["in", "instanceof"];
+var ALL_OPERATORS = [].concat(
+    ARITHMETIC_OPERATORS,
+    BITWISE_OPERATORS,
+    COMPARISON_OPERATORS,
+    LOGICAL_OPERATORS,
+    RELATIONAL_OPERATORS
+);
+var DEFAULT_GROUPS = [
+    ARITHMETIC_OPERATORS,
+    BITWISE_OPERATORS,
+    COMPARISON_OPERATORS,
+    LOGICAL_OPERATORS,
+    RELATIONAL_OPERATORS
+];
+var TARGET_NODE_TYPE = /^(?:Binary|Logical)Expression$/;
+
+/**
+ * Normalizes options.
+ *
+ * @param {object|undefined} options - A options object to normalize.
+ * @returns {object} Normalized option object.
+ */
+function normalizeOptions(options) {
+    var hasGroups = (options && options.groups && options.groups.length > 0);
+    var groups = hasGroups ? options.groups : DEFAULT_GROUPS;
+    var allowSamePrecedence = (options && options.allowSamePrecedence) !== false;
+
+    return {
+        groups: groups,
+        allowSamePrecedence: allowSamePrecedence
+    };
+}
+
+/**
+ * Checks whether any group which includes both given operator exists or not.
+ *
+ * @param {Array.<string[]>} groups - A list of groups to check.
+ * @param {string} left - An operator.
+ * @param {string} right - Another operator.
+ * @returns {boolean} `true` if such group existed.
+ */
+function includesBothInAGroup(groups, left, right) {
+    return groups.some(function(group) {
+        return group.indexOf(left) !== -1 && group.indexOf(right) !== -1;
+    });
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow mixed binary operators",
+            category: "Stylistic Issues",
+            recommended: false
+        },
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    groups: {
+                        type: "array",
+                        items: {
+                            type: "array",
+                            items: {enum: ALL_OPERATORS},
+                            minItems: 2,
+                            uniqueItems: true
+                        },
+                        uniqueItems: true
+                    },
+                    allowSamePrecedence: {
+                        type: "boolean"
+                    }
+                },
+                additionalProperties: false
+            }
+        ]
+    },
+
+    create: function(context) {
+        var sourceCode = context.getSourceCode();
+        var options = normalizeOptions(context.options[0]);
+
+        /**
+         * Checks whether a given node should be ignored by options or not.
+         *
+         * @param {ASTNode} node - A node to check. This is a BinaryExpression
+         *      node or a LogicalExpression node. This parent node is one of
+         *      them, too.
+         * @returns {boolean} `true` if the node should be ignored.
+         */
+        function shouldIgnore(node) {
+            var a = node;
+            var b = node.parent;
+
+            return (
+                !includesBothInAGroup(options.groups, a.operator, b.operator) ||
+                (
+                    options.allowSamePrecedence &&
+                    astUtils.getPrecedence(a) === astUtils.getPrecedence(b)
+                )
+            );
+        }
+
+        /**
+         * Checks whether the operator of a given node is mixed with parent
+         * node's operator or not.
+         *
+         * @param {ASTNode} node - A node to check. This is a BinaryExpression
+         *      node or a LogicalExpression node. This parent node is one of
+         *      them, too.
+         * @returns {boolean} `true` if the node was mixed.
+         */
+        function isMixedWithParent(node) {
+            return (
+                node.operator !== node.parent.operator &&
+                !astUtils.isParenthesised(sourceCode, node)
+            );
+        }
+
+        /**
+         * Gets the operator token of a given node.
+         *
+         * @param {ASTNode} node - A node to check. This is a BinaryExpression
+         *      node or a LogicalExpression node.
+         * @returns {Token} The operator token of the node.
+         */
+        function getOperatorToken(node) {
+            var token = sourceCode.getTokenAfter(node.left);
+
+            while (token.value === ")") {
+                token = sourceCode.getTokenAfter(token);
+            }
+
+            return token;
+        }
+
+        /**
+         * Reports both the operator of a given node and the operator of the
+         * parent node.
+         *
+         * @param {ASTNode} node - A node to check. This is a BinaryExpression
+         *      node or a LogicalExpression node. This parent node is one of
+         *      them, too.
+         * @returns {void}
+         */
+        function reportBothOperators(node) {
+            var parent = node.parent;
+            var left = (parent.left === node) ? node : parent;
+            var right = (parent.left !== node) ? node : parent;
+            var message =
+                "Unexpected mix of '" + left.operator + "' and '" +
+                right.operator + "'.";
+
+            context.report({
+                node: left,
+                loc: getOperatorToken(left).loc.start,
+                message: message
+            });
+            context.report({
+                node: right,
+                loc: getOperatorToken(right).loc.start,
+                message: message
+            });
+        }
+
+        /**
+         * Checks between the operator of this node and the operator of the
+         * parent node.
+         *
+         * @param {ASTNode} node - A node to check.
+         * @returns {void}
+         */
+        function check(node) {
+            if (TARGET_NODE_TYPE.test(node.parent.type) &&
+                isMixedWithParent(node) &&
+                !shouldIgnore(node)
+            ) {
+                reportBothOperators(node);
+            }
+        }
+
+        return {
+            BinaryExpression: check,
+            LogicalExpression: check
+        };
+    }
+};