Accept multiple input nodes

lib/index.js

@@ -12,10 +12,11 @@ const isString = require('./is-string');
 const getResultSeverity = require('./get-result-severity');
 const testGenerators = require('./test-generators');
 const testGeneratorNames = Object.keys(testGenerators);
+const nodeIncludesOverrides = require('./node-includes-overrides');
 
 const FACTORY_METHOD_USED = Symbol('create() factory method was used');
 
-function resolveInputDirectory(inputNode) {
+function resolveInputDirectory(inputNode, eslintIncludesOverrides) {
   if (typeof inputNode === 'string') {
     return inputNode;
   }
@@ -27,12 +28,14 @@ function resolveInputDirectory(inputNode) {
     return nodeInfo.sourceDirectory;
   }
 
-  if (nodeInfo.inputNodes.length > 1) {
+  if (nodeInfo.inputNodes.length > 1 && !eslintIncludesOverrides) {
     // eslint-disable-next-line max-len
-    throw new Error('EslintValidationFilter can only handle one:* broccoli nodes, but part of the given input pipeline is a many:* node. (broccoli-merge-trees is an example of a many:* node) Please perform many:* operations after linting.');
+    throw new Error(
+      'EslintValidationFilter can only handle one:* broccoli nodes, but part of the given input pipeline is a many:* node. (broccoli-merge-trees is an example of a many:* node) Please perform many:* operations after linting.'
+    );
   }
 
-  return resolveInputDirectory(nodeInfo.inputNodes[0]);
+  return resolveInputDirectory(nodeInfo.inputNodes[0], eslintIncludesOverrides);
 }
 
 /**
@@ -80,7 +83,10 @@ function EslintValidationFilter(inputNode, options) {
 
   this.cli = new CLIEngine(options.options);
 
-  this.eslintrc = resolveInputDirectory(inputNode);
+  this.eslintrc = resolveInputDirectory(
+    inputNode,
+    nodeIncludesOverrides(inputNode, this.cli)
+  );
 
   if (isString(this.internalOptions.testGenerator)) {
     this.testGenerator = testGenerators[this.internalOptions.testGenerator];

lib/node-includes-overrides.js

@@ -0,0 +1,36 @@
+/**
+ * Uses eslint (private) api to see if eslint config includes a `overrides` flag.
+ *
+ * inputNode type is a bit tricky here. We are expecting three different cases:
+ * if it's string, we will use it as a directory and let eslint do the work.
+ *
+ * if it's a source node, use the `sourceDirectory` property.
+ *
+ * if it's a transform node, recursively call same function with all of its
+ * inputNodes. if any of the input directories contain `overrides` eslint
+ * config, return true
+ *
+ * While it's not ideal we iterate through all the `inputNodes` of a transform node,
+ * the input size should be very small.
+ */
+const nodeIncludesOverrides = (inputNode, eslintCli) => {
+  if (typeof inputNode === 'string') {
+    return eslintCli.config
+      .getConfigHierarchy(inputNode)
+      .some(node => node.overrides);
+  }
+
+  const nodeInfo = inputNode.__broccoliGetInfo__();
+  const nodeType = nodeInfo.nodeType;
+  const sourceDirectory = nodeInfo.sourceDirectory;
+  if (nodeType === 'transform') {
+    const nodesIncludesOverrides = inputNode._inputNodes.map(node =>
+      nodeIncludesOverrides(node, eslintCli)
+    );
+    return nodesIncludesOverrides.some(Boolean);
+  }
+
+  return nodeIncludesOverrides(sourceDirectory, eslintCli);
+};
+
+module.exports = nodeIncludesOverrides;

package.json

@@ -3,6 +3,9 @@
   "version": "4.2.1",
   "description": "broccoli filter that runs eslint",
   "main": "lib/index.js",
+  "engines": {
+    "node": ">=4"
+  },
   "scripts": {
     "lint": "eslint .",
     "test": "mocha test/*test.js test/**/*test.js"

test/eslint-test.js

@@ -61,6 +61,39 @@ describe('broccoli-lint-eslint', function() {
       .to.contain(`DEPRECATION: Please use the create() factory method`);
   }));
 
+  it('accept many:* node if eslintrc specifies overrides', co.wrap(function*() {
+    // we need to create two temp folders with eslintrc files in it
+    const firstDirectory = yield createTempDir();
+    const secondDirectory = yield createTempDir();
+
+    firstDirectory.write({
+      '.eslintrc.js': `module.exports = { rules: { 'no-console': 'error'}, overrides: [ { files: 'a.js', rules: { 'no-console': 'disable' } }] }`,
+      'a.js': `console.log('foo');\n`,
+    });
+
+    secondDirectory.write({
+      '.eslintrc.js': `module.exports = { }`,
+      'a.js': `console.log('foo');\n`,
+    });
+
+    let messages = [];
+    let console = {
+      log(message) {
+        messages.push(message);
+      },
+    };
+
+    const mergedDirectories = new MergeTrees([
+      firstDirectory.path(),
+      secondDirectory.path(),
+    ]);
+
+    expect(() => new ESLint(mergedDirectories, { console })).to.not.throw();
+
+    yield firstDirectory.dispose();
+    yield secondDirectory.dispose();
+  }));
+
   it('logs errors to the console (using new)', co.wrap(function *() {
     input.write({
       '.eslintrc.js': `module.exports = { rules: { 'no-console': 'error', 'no-unused-vars': 'warn' } };\n`,