In differential testing we usually compare the output of two shells running with different options (e.g. TI vs. Interp) and there are quite a few functions that behave differently under those options or even completely non-deterministic. While we can remove or wrap most of those functions at runtime, some obstacles remain. The attached patch does two things: It makes gc() return an empty string (Jesse mentioned on IRC that wrapping gc() could cause problems) and it makes js_ReportOverRecursed print out a notice on stderr when it is called. The reason for that notice is to recognize when a test hits the recursion limit so we can ignore it, as the recursion limits across different options is not consistent. Both modifications are not enabled unless the --enable-more-deterministic flag is passed at compile time.

Comment on attachment 577920 [details] [diff] [review] Patch Review of attachment 577920 [details] [diff] [review]: ----------------------------------------------------------------- r=me with the nit below. ::: js/src/shell/js.cpp @@ +1212,5 @@ > > char buf[256]; > +#ifdef JS_MORE_DETERMINISTIC > + JS_snprintf(buf, sizeof(buf), ""); > +#else Just buf[0] = '\0'; here please.

Updated patch to fix the nit. Jason, can you check this in?

Comment on attachment 578429 [details] [diff] [review] Updated patch r+ taken from first patch.

Landed on m-i: http://hg.mozilla.org/integration/mozilla-inbound/rev/f0159088a7c3