[BUGFIX release] Fix uglification introduced bug with super wrapping.

[rwjblue]

We check to see if a function contains _super / .call / .apply before attempting to super wrap a given method (this saves quite a bit of extra super wrapping for functions that do not need it). Unfortunately, a number of platforms that we support do not support calling func.toString() so we attempt to detect this and fall back to always super wrap everything mode.

We have roughly this code (from here) to detect if we can call toString() and get the original source:

  let sourceAvailable = (function() {
    return this;
  }).toString().indexOf('return this;') > -1;

This works perfectly for development builds, but unfortunately not when minified. Take a look at the minified source and you will see why:

var e=function(){return this}.toString().indexOf("return this;")>-1;

Note that minifier has stripped the trailing semicolon from the function body we are attempting to check against, but sadly our indexOf check still contains the semicolon!

tldr; We super wrap every function in uglified builds.

---

This commit removes the trailing semicolon from the source check, and adds a test that should hopefully allow us to detect if this is accidentally reintroduced.

Fixes #12462.

[stefanpenner]

Lgtm

[ef4]

LGTM.

The test will fail on platforms that don't support Function.toString, but that is kinda the point of the test: detecting unnecessary super wrapping, which those platforms unfortunately do have.

[rwjblue]

We could add a phantomjs detection to https://github.com/emberjs/ember.js/blob/master/packages/ember-metal/lib/environment.js#L27-L28, and wrap the test in a if (env.isPhantom || env.isChrome || env.isFirefox). This allows the test suite to pass on other browers that may or may not need the "always wrap" fallback path, but ensures we continue to pass on browsers that we know should support function() { }.toString().

Thoughts?

[rwjblue]

Added the phantomjs check I mentioned above, the test suite should now continue to pass even on platforms that do not support function source.

[ef4]

👍

[dschmidt]

Awesome, thanks!

[stefanpenner]

this is likely going to be a nice little perf post, since i suppose we where super wrapping many more things before.