CLI: Support a maxErrors option to limit the number of reported errors

Closes jscs-devgh-664
Fixes jscs-dev#238

bin/jscs

@@ -18,6 +18,7 @@ program
     .option('-p, --preset <preset>', 'preset config')
     .option('-r, --reporter <reporter>', 'error reporter, console - default, text, checkstyle, junit, inline')
     .option('-v, --verbose', 'adds rule names to the error output')
+    .option('-m, --max-errors <number>', 'maximum number of errors to report')
     .option('', 'Also accepts relative or absolute path to custom reporter')
     .option('', 'For instance:')
     .option('', '\t  ../some-dir/my-reporter.js\t(relative path with extension)')

lib/checker.js

@@ -31,6 +31,8 @@ Checker.prototype.configure = function(config) {
     excludeFiles(config, this, cwd);
     additionalRules(config, this, cwd);
 
+    this._maxErrors = config.maxErrors || 50;
+
     StringChecker.prototype.configure.apply(this, arguments);
 };
 

lib/cli.js

@@ -82,6 +82,10 @@ module.exports = function(program) {
         config.preset = program.preset;
     }
 
+    if (program.maxErrors) {
+        config.maxErrors = Number(program.maxErrors);
+    }
+
     if (program.reporter) {
         reporterPath = path.resolve(process.cwd(), program.reporter);
         returnArgs.reporter = reporterPath;

lib/errors.js

@@ -32,6 +32,11 @@ Errors.prototype = {
             return;
         }
 
+        // We're trying to add more than the max number of errors
+        if (typeof Errors.maxErrors !== 'undefined' && this.getErrorCount() === Errors.maxErrors) {
+            throw new Error();
+        }
+
         this._errorList.push({
             rule: this._currentRule,
             message: this._verbose ? this._currentRule + ': ' + message : message,

lib/string-checker.js

@@ -164,6 +164,11 @@ StringChecker.prototype = {
 
         preset.extend(config);
 
+        // Static property to limit the total number of errors reported
+        Errors.maxErrors = config.maxErrors || 50;
+        // To avoid being mistaken for an unsupported rule
+        delete config.maxErrors;
+
         var configRules = Object.keys(config);
         var activeRules = this._activeRules;
 
@@ -245,25 +250,33 @@ StringChecker.prototype = {
         } catch (e) {
             parseError = e;
         }
+
         var file = new JsFile(filename, str, tree);
         var errors = new Errors(file, this._verbose);
 
         if (parseError) {
             errors.setCurrentRule('parseError');
-            errors.add(parseError.description, parseError.lineNumber, parseError.column);
+            try {
+                errors.add(parseError.description, parseError.lineNumber, parseError.column);
+            } catch (e) {}
 
             return errors;
         }
 
-        this._activeRules.forEach(function(rule) {
+        var rule;
+        for (var i = 0, l = this._activeRules.length; i < l; i++) {
+            rule = this._activeRules[i];
 
             // Do not process the rule if it's equals to null (#203)
             if (this._config[rule.getOptionName()] !== null) {
                 errors.setCurrentRule(rule.getOptionName());
-                rule.check(file, errors);
+                try {
+                    rule.check(file, errors);
+                } catch (e) {
+                    break;
+                }
             }
-
-        }, this);
+        }
 
         // sort errors list to show errors as they appear in source
         errors.getErrorList().sort(function(a, b) {

test/cli.js

@@ -524,4 +524,27 @@ describe('modules/cli', function() {
             });
         });
     });
+
+    describe('maxErrors option', function() {
+        beforeEach(function() {
+            sinon.spy(console, 'log');
+        });
+
+        afterEach(function() {
+            console.log.restore();
+        });
+
+        it('should limit the number of errors reported to the provided amount', function(done) {
+            return cli({
+                maxErrors: 1,
+                args: ['test/data/cli/error.js'],
+                config: 'test/data/cli/maxErrors.json'
+            })
+            .promise.always(function() {
+                assert(console.log.getCall(1).args[0].indexOf('1 code style error found.') !== -1);
+                rAfter();
+                done();
+            });
+        });
+    });
 });

test/data/cli/maxErrors.json

@@ -0,0 +1,4 @@
+{
+  "disallowKeywords": ["with"],
+  "requireSpaceBeforePostfixUnaryOperators": ["++"]
+}

test/rules/validate-indentation.js

@@ -36,7 +36,7 @@ describe('rules/validate-indentation', function() {
     });
 
     it('should validate 2 spaces indentation properly', function() {
-        checker.configure({ validateIndentation: 2 });
+        checker.configure({ validateIndentation: 2, maxErrors: 500 });
         checkErrors(fixture, [
             5,
             10,