Add message to error stack

[calebmer]

Because of an ordering bug messages weren’t being added to the error stacks thrown by Prepack. This made debugging runtime issues in generated Prepack code difficult.

Input

throw new Error("foo");

Output Before

(function() {
  var $$0 = {
    enumerable: false,
    configurable: true,
    writable: true,
  };

  var _$0 = this;

  var _$1 = _$0.Error;
  var _$2 = _$1.prototype;
  var _$3 = _$0.Object;
  var _$4 = _$3.defineProperty;

  var __constructor = function() {};

  var _0 = ((__constructor.prototype = _$2), new __constructor());

  ($$0.value = "Error\n    at /Users/calebmer/prepack/fb-www/input.js:4:7"), _$4(_0, "stack", $$0);
  ($$0.value = "foo"), _$4(_0, "message", $$0);
  throw _0;
}.call(this));

Output After

(function() {
  var $$0 = {
    enumerable: false,
    configurable: true,
    writable: true,
  };

  var _$0 = this;

  var _$1 = _$0.Error;
  var _$2 = _$1.prototype;
  var _$3 = _$0.Object;
  var _$4 = _$3.defineProperty;

  var __constructor = function() {};

  var _0 = ((__constructor.prototype = _$2), new __constructor());

  ($$0.value = "foo"), _$4(_0, "message", $$0);
  ($$0.value = "Error: foo\n    at /Users/calebmer/prepack/fb-www/input.js:4:7"), _$4(_0, "stack", $$0);
  throw _0;
}.call(this));

[hermanventer]

The failing test needs to be addressed.

[hermanventer]

buildStack does not yet handle abstract messages. You can add such support by emitting the stack as a string template. Alternatively, you could just comment out the throw with a TODO comment, along with an issue describing what needs to be done.

[calebmer]

👍

[hermanventer]

You still need to fix a Flow error, but other than that it looks good to me.

[facebook-github-bot]

@calebmer is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.