fix: handle negative gitignore patterns correctly

*  split out getGitIgnores from getIgnores
*  adapt test cases accordingly
*  extend gitignore test case with negative pattern
*  invert gitignore patterns and feed sotred as glob instead of opts.ignore

fix #154

index.js

@@ -26,10 +26,12 @@ exports.lintText = (str, opts) => {
 		throw new Error('The `ignores` option requires the `filename` option to be defined.');
 	}
 
-	if (opts.ignores && opts.ignores.length > 0 && opts.filename) {
+	if (opts.filename) {
+		const gitIgnores = optionsManager.getGitIgnores(opts);
 		const filename = path.relative(opts.cwd, opts.filename);
+		const glob = [filename].concat(gitIgnores);
 
-		if (multimatch([filename], opts.ignores).length > 0) {
+		if (multimatch(glob, opts.ignores).length > 0) {
 			return {
 				errorCount: 0,
 				warningCount: 0,
@@ -49,14 +51,18 @@ exports.lintText = (str, opts) => {
 	return processReport(report, opts);
 };
 
-exports.lintFiles = (patterns, opts) => {
+exports.lintFiles = (pattern, opts) => {
 	opts = optionsManager.preprocess(opts);
 
-	if (patterns.length === 0) {
-		patterns = '**/*';
+	if (pattern.length === 0) {
+		pattern = '**/*';
 	}
 
-	return globby(patterns, {ignore: opts.ignores}).then(paths => {
+	const gitIgnores = optionsManager.getGitIgnores(opts);
+	const patterns = Array.isArray(pattern) ? pattern : [pattern];
+	const glob = patterns.concat(gitIgnores);
+
+	return globby(glob, {ignore: opts.ignores}).then(paths => {
 		// filter out unwanted file extensions
 		// for silly users that don't specify an extension in the glob pattern
 		paths = paths.filter(x => {

options-manager.js

@@ -222,24 +222,30 @@ function groupConfigs(paths, baseOptions, overrides) {
 
 function getIgnores(opts) {
 	opts.ignores = DEFAULT_IGNORE.concat(opts.ignores || []);
+	return opts;
+}
 
+function getGitIgnores(opts) {
 	const gitignores = globby.sync('**/.gitignore', {
-		ignore: opts.ignores,
+		ignore: opts.ignores || [],
 		cwd: opts.cwd || process.cwd()
 	});
 
-	const ignores = gitignores
+	return gitignores
 		.map(pathToGitignore => {
 			const patterns = parseGitignore(pathToGitignore);
 			const base = path.dirname(pathToGitignore);
 
-			return patterns.map(file => path.join(base, file));
+			return patterns
+				.map(pattern => {
+					const negate = !pattern.startsWith('!');
+					const patternPath = negate ? pattern : pattern.substr(1);
+					return {negate, pattern: path.join(base, patternPath)};
+				})
+				.sort(pattern => pattern.negate ? 1 : -1)
+				.map(item => item.negate ? `!${item.pattern}` : item.pattern);
 		})
 		.reduce((a, b) => a.concat(b), []);
-
-	opts.ignores = opts.ignores.concat(ignores);
-
-	return opts;
 }
 
 function preprocess(opts) {
@@ -262,3 +268,4 @@ exports.groupConfigs = groupConfigs;
 exports.preprocess = preprocess;
 exports.emptyOptions = emptyOptions;
 exports.getIgnores = getIgnores;
+exports.getGitIgnores = getGitIgnores;

test/.gitignore

@@ -1,2 +1,3 @@
 # This is a test .gitignore.
 foo/
+!bar.js

test/bar/.gitignore

@@ -1 +1,2 @@
 foo.js
+!bar.js

test/options-manager.js

@@ -173,9 +173,10 @@ test('groupConfigs', t => {
 });
 
 test('gitignore', t => {
-	const result = manager.getIgnores({});
-	t.not(result.ignores.indexOf(path.join('foo', '**')), -1);
-	t.not(result.ignores.indexOf(path.join('bar', 'foo.js')), -1);
+	const ignores = manager.getGitIgnores({});
+	t.not(ignores.indexOf('!' + path.join('foo', '**')), -1);
+	t.not(ignores.indexOf('!' + path.join('bar', 'foo.js')), -1);
+	t.not(ignores.indexOf(path.join('bar', 'bar.js')), -1);
 });
 
 test('ignore ignored .gitignore', t => {
@@ -185,9 +186,8 @@ test('ignore ignored .gitignore', t => {
 		]
 	};
 
-	const result = manager.getIgnores(opts);
-
-	t.is(result.ignores.indexOf(path.join('bar', 'foobar', 'bar.js')), -1);
+	const ignores = manager.getGitIgnores(opts);
+	t.is(ignores.indexOf('!' + path.join('bar', 'foobar', 'bar.js')), -1);
 });
 
 test('mergeWithPkgConf: use child if closest', t => {