On vr, 2015-05-15 at 04:38 -0400, Jeff King wrote: > On Fri, May 15, 2015 at 09:41:20AM +0200, Dennis Kaarsemaker wrote: > > > > I have no clue how to write a test that would trigger this reliably > > > without requiring a gigantic test fixture. However, I did confirm that > > > it fixes the problem on the chromium case you provided (which otherwise > > > deadlocks reliably for me). > > > > This looks similar to the failure I posted about alst year in > > http://thread.gmane.org/gmane.comp.version-control.git/258514 > > > > Though the issue is different, it has the same 'hanging git fetch' > > symptom due to the deadlock between upload-pack and http-backend. > > Thanks, I think it is the same issue (in the end I was replicating not > with `--reference`, but just by doing a fetch from the other > repository). And our solutions are essentially the same. I do prefer > mine because: > > 1. It keeps the buffering logic in http-backend; the half-duplex > nature is an http detail. > > 2. I think it's better to buffer the request rather than the response, > for the reasons I stated in the commit message. > > > The patch I sent back then is suboptimal, as it can cause larger packs > > than necessary (we still use it though, as the alternative is a > > non-working git), but it does include a test you may be able to use to > > verify your fix, if this is indeed the same issue. > > I applied the test from your patch, but couldn't get it to fail even > with stock git. The test above it shrunk a bit, but I was able to tweak > yours to generate tags from 2001..100000, which I thought would have > worked. I suspect it's something silly like the size not being quite > big enough for the pipe buffer on my system, or something like that. > Though I couldn't get it to fail even with 200,000 tags, so perhaps it's > something else. The shrinkage in the test above it will actually work around the issue, as there are now fewer already-fetched tags to negotiate. Either reverting that shrinkage or executing the new test twice should do the trick. -- Dennis Kaarsemaker http://www.kaarsemaker.net -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html