cmd/go: go get -u=patch hangs while using CPU while 1.17.1 doesn't #48511
Description
This seems to be a regression in master since 1.17 was released.
Repro steps below; luckily, I encountered the hang in an open source module repo.
$ cd /tmp
$ git clone https://github.com/vocdoni/vocdoni-node
$ cd vocdoni-node/
$ git checkout 31d448d170f6be0537f775772a710a59208317b3
$ go version
go version devel go1.18-c7543e5db9 Tue Sep 21 03:15:20 2021 +0000 linux/amd64
$ go get -d -u=patch ./...
(may download some modules, then hangs forever, using ~300% CPU; I kill it after one minute)
^C
$ wgo1 go version
go version go1.17.1 linux/amd64
$ wgo1 go get -d -u=patch ./...
go get: upgraded github.com/DataDog/zstd v1.4.5 => v1.4.8
go get: upgraded github.com/Workiva/go-datastructures v1.0.52 => v1.0.53
[more lines, then finishes successfully]
I haven't narrowed down the reproducer or bisected just yet. I think this might be enough information for @bcmills or @jayconrod to have a good guess as to what recent change added this hang.
I tried using ^\ to get a stack trace of the process, but I get seemingly harmless stack traces that show cmd/go doing work, so perhaps the endless loop is at a higher level - for example, loading the same package over and over again.
Marking as release-blocker for now, as it looks like a regression.