x/exp: breaking changes support

[AskAlexSharov]

github.com/lispad/go-generics-tools is not compatible with recent x/exp breaking changes: they change API of sorting functions from Less bool to Compare int for example slices.SortFunc

github.com/lispad/go-generics-tools@v1.1.0/binheap/topstream.go:48:26: type func(x T, y T) bool of h.comparator does not match inferred type func(a T, b T) int for func(a E, b E) int

does it make sense for+upgrade go-generics-tools or switch to some other binheap?

There is using Multiless package - which also (maybe) not compatible with Compare int API.

x/exp did change API because of new go1.21 package cmp: https://pkg.go.dev/cmp

[anacrolix]

I am disappointed that Ian Lance Taylor is curmudgeonly about so many changes but is happy to break this needlessly.

I have switched to a genericized version of the standard library heap instead.

[AskAlexSharov]

@anacrolix hi. seems this commit - introduced some deadlock. CI is red https://github.com/anacrolix/torrent/actions/runs/5877936323/job/15939030611 and my app can't shutdown on ctrl+c

not sure - if it's related, i see next trace:

1: 6144 [1: 6144] @ 0x1007e0646 0x100091379 0x1007e3e8e 0x1007e3e74 0x1007e378e 0x1007e181c 0x1007df7ed 0x1007df78a 0x1007e014a 0x1009988b4 0x10099a726 0x10099aa87 0x1009a1518 0x100974dd0 0x100974cb4 0x10152b6bc 0x10152a139 0x101527132 0x1005b12e4 0x1000735a1
#   0x1007e0645 github.com/ajwerner/btree/internal/abstract.getNodePool[...].func1+0x25         github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/internal/abstract/node_pool.go:39
#   0x100091378 sync.(*Pool).Get+0xb8                                   sync/pool.go:151
#   0x1007e3e8d github.com/ajwerner/btree/internal/abstract.(*nodePool[...]).getLeafNode+0x10d      github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/internal/abstract/node_pool.go:59
#   0x1007e3e73 github.com/ajwerner/btree/internal/abstract.(*Node[...]).split+0xf3         github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/internal/abstract/node.go:287
#   0x1007e378d github.com/ajwerner/btree/internal/abstract.(*Node[...]).insert+0x1ad           github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/internal/abstract/node.go:357
#   0x1007e181b github.com/ajwerner/btree/internal/abstract.(*Map[...]).Upsert+0x2fb            github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/internal/abstract/aug_btree.go:127
#   0x1007df7ec github.com/ajwerner/btree.(*Set[...]).Upsert+0x8c                   github.com/ajwerner/btree@v0.0.0-20211221152037-f427b3e689c0/btree.go:52
#   0x1007df789 github.com/anacrolix/torrent/request-strategy.(*ajwernerBtree).Add+0x29         github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/request-strategy/ajwerner-btree.go:32
#   0x1007e0149 github.com/anacrolix/torrent/request-strategy.(*PieceRequestOrder).Add+0xc9     github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/request-strategy/piece-request-order.go:47
#   0x1009988b3 github.com/anacrolix/torrent.(*Torrent).addRequestOrderPiece+0xf3           github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/torrent-piece-request-order.go:58
#   0x10099a725 github.com/anacrolix/torrent.(*Torrent).onSetInfo+0x1a5                 github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/torrent.go:485
#   0x10099aa86 github.com/anacrolix/torrent.(*Torrent).setInfoBytesLocked+0x1a6            github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/torrent.go:520
#   0x1009a1517 github.com/anacrolix/torrent.(*Torrent).SetInfoBytes+0x97               github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/torrent.go:1531
#   0x100974dcf github.com/anacrolix/torrent.(*Torrent).MergeSpec+0x8f                  github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/client.go:1414
#   0x100974cb3 github.com/anacrolix/torrent.(*Client).AddTorrentSpec+0x133             github.com/anacrolix/torrent@v1.52.6-0.20230823215932-b836d2ad53ee/client.go:1399

[anacrolix]

I think the CI tests are just a bit flakey. I'm not sure this commit introduced the issue. I could be wrong.

[AskAlexSharov]

Seems I did mistake when tested rollback to prev version. Seems my app stuck on prev version also. Then ball on my side for now.

[anacrolix]

I've pushed https://github.com/anacrolix/torrent/compare/generic-heap-ci-revert?expand=1 to test your theory, but I'm pretty sure it's just flakey tests. Thanks for following up.

[AskAlexSharov]

seems i fixed my app shutdown issue. not related to the torrent lib. thank you.

[anacrolix]

There is an significant issue caused by the heap change. I'm investigating.

[anacrolix]

There was serious behaviour bug fixed in 87f6cdc1e96fdd846bb9c55cfd5176a17373d4b6.