fix: context should override parsed argv (#786)

BREAKING CHANGE: context now takes precedence over argv and defaults

test/yargs.js

@@ -768,6 +768,14 @@ describe('yargs dsl tests', function () {
       a1.foo.should.equal('bar')
       a1.context.should.equal('look at me go!')
     })
+
+    // see https://github.com/yargs/yargs/issues/724
+    it('overrides parsed value of argv with context object', function () {
+      var a1 = yargs.parse('-x=33', {
+        x: 42
+      })
+      a1.x.should.equal(42)
+    })
   })
 
   // yargs.parse(['foo', '--bar'], function (err, argv, output) {}

yargs.js

@@ -935,7 +935,7 @@ function Yargs (processArgs, cwd, parentRequire) {
     options.configuration = pkgUp()['yargs'] || {}
     const parsed = Parser.detailed(args, options)
     var argv = parsed.argv
-    if (parseContext) argv = assign(parseContext, argv)
+    if (parseContext) argv = assign(argv, parseContext)
     var aliases = parsed.aliases
 
     argv.$0 = self.$0