really, the big problem was that the HHVM team didn't use CMake, so there was no concern with how long the build took and it was frequently broken. I had two instances where I spent hours fixing bugs that were fixed internally at FB at the same time, but hadn't been pushed. I know there was an ongoing effort to move completely into the open, but it was frustrating. I don't think these are persistent problems with HHVM, just reasons why the project wasn't really ready for primetime in the OSS world (open academy, specifically).
the fact that no one who doesn't work at FB is allowed to merge code (correct me if I'm wrong) made me feel like I was helping FB more than the OSS community. I get that HHVM is business critical to FB, but if you want it to truly get community support it needs to be spun off from FB.
edit: and I will add that my language was way too harsh. it's not hard to get in a PR provided it doesn't break anything in an FB internal test suite which I can't see (which never was a problem for me, but I could see it being one) and didn't degrade FB performance.
the fact that no one who doesn't work at FB is allowed to merge code (correct me if I'm wrong) made me feel like I was helping FB more than the OSS community. I get that HHVM is business critical to FB, but if you want it to truly get community support it needs to be spun off from FB.
edit: and I will add that my language was way too harsh. it's not hard to get in a PR provided it doesn't break anything in an FB internal test suite which I can't see (which never was a problem for me, but I could see it being one) and didn't degrade FB performance.