fix: ignore invalid package.json during read-pkg-up (#546)

test/fixtures/broken-json/package.json

@@ -0,0 +1 @@
+{'foo': bar}

test/yargs.js

@@ -945,6 +945,15 @@ describe('yargs dsl tests', function () {
       argv.foo.should.equal('a')
       argv.dotNotation.should.equal(false)
     })
+
+    // see https://github.com/yargs/yargs/issues/485
+    it('handles an invalid package.json', function () {
+      var argv = yargs('--foo a')
+        .pkgConf('yargs', './test/fixtures/broken-json')
+        .argv
+
+      argv.foo.should.equal('a')
+    })
   })
 
   describe('skipValidation', function () {

yargs.js

@@ -360,9 +360,12 @@ function Yargs (processArgs, cwd, parentRequire) {
     if (pkg && !path) return pkg
     const readPkgUp = require('read-pkg-up')
 
-    var obj = readPkgUp.sync({
-      cwd: path || requireMainFilename(parentRequire || require)
-    })
+    var obj = {}
+    try {
+      obj = readPkgUp.sync({
+        cwd: path || requireMainFilename(parentRequire || require)
+      })
+    } catch (noop) {}
 
     if (obj.pkg) pkg = obj.pkg
     return pkg || {}