tools: move eslint from tools to tools/node_modules

This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.

Refs: https://github.com/nodejs/node/pull/17755
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/tools/node_modules/eslint/lib/rules/handle-callback-err.js b/tools/node_modules/eslint/lib/rules/handle-callback-err.js
new file mode 100644
index 0000000000..de36a0c1b0
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/handle-callback-err.js
@@ -0,0 +1,89 @@
+/**
+ * @fileoverview Ensure handling of errors when we know they exist.
+ * @author Jamund Ferguson
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "require error handling in callbacks",
+            category: "Node.js and CommonJS",
+            recommended: false
+        },
+
+        schema: [
+            {
+                type: "string"
+            }
+        ]
+    },
+
+    create(context) {
+
+        const errorArgument = context.options[0] || "err";
+
+        /**
+         * Checks if the given argument should be interpreted as a regexp pattern.
+         * @param {string} stringToCheck The string which should be checked.
+         * @returns {boolean} Whether or not the string should be interpreted as a pattern.
+         */
+        function isPattern(stringToCheck) {
+            const firstChar = stringToCheck[0];
+
+            return firstChar === "^";
+        }
+
+        /**
+         * Checks if the given name matches the configured error argument.
+         * @param {string} name The name which should be compared.
+         * @returns {boolean} Whether or not the given name matches the configured error variable name.
+         */
+        function matchesConfiguredErrorName(name) {
+            if (isPattern(errorArgument)) {
+                const regexp = new RegExp(errorArgument);
+
+                return regexp.test(name);
+            }
+            return name === errorArgument;
+        }
+
+        /**
+         * Get the parameters of a given function scope.
+         * @param {Object} scope The function scope.
+         * @returns {array} All parameters of the given scope.
+         */
+        function getParameters(scope) {
+            return scope.variables.filter(variable => variable.defs[0] && variable.defs[0].type === "Parameter");
+        }
+
+        /**
+         * Check to see if we're handling the error object properly.
+         * @param {ASTNode} node The AST node to check.
+         * @returns {void}
+         */
+        function checkForError(node) {
+            const scope = context.getScope(),
+                parameters = getParameters(scope),
+                firstParameter = parameters[0];
+
+            if (firstParameter && matchesConfiguredErrorName(firstParameter.name)) {
+                if (firstParameter.references.length === 0) {
+                    context.report({ node, message: "Expected error to be handled." });
+                }
+            }
+        }
+
+        return {
+            FunctionDeclaration: checkForError,
+            FunctionExpression: checkForError,
+            ArrowFunctionExpression: checkForError
+        };
+
+    }
+};