Bump github.com/cloudflare/tableflip from 1.2.0 to 1.2.1

[dependabot]

Bumps github.com/cloudflare/tableflip from 1.2.0 to 1.2.1.

Release notes

Sourced from github.com/cloudflare/tableflip's releases.

Fix clearing O_NONBLOCK on upgrade

The Go runtime has annoying behaviour around setting and clearing O_NONBLOCK: exec.Cmd.Start() ends up calling os.File.Fd() for any file in exec.Cmd.ExtraFiles. os.File.Fd() disables both the use of the runtime poller for the file and clears O_NONBLOCK from the underlying open file descriptor.

This can lead to goroutines hanging in a parent process, after at least one failed upgrade. The bug manifests by goroutines which rely on either a deadline or interruption via Close() to be unblocked being stuck in read or accept like syscalls,. As far as I can tell we've not experienced this problem in production, so it's most likely quite rare.

Commits

• cae714b ensure that inherited files are nonblocking
• 57f992b require Go 1.14
• 5f43f42 remove go 1.12 compatibility
• 4b4e680 migrate to github actions
• 77aba94 Refactor some methods to take advantage of the new *WithCallback methods
• 40abd35 Allow opening connection with callbacks
• 4baec98 Add ListenConfig as Option to Upgrader
• See full diff in compare view

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