Go 1.18 deprecated net.Error.Temporary().
This commit cleans up places where we use it incorrectly.
Also, the rpc layer defines some errors that implement
interface { Temporary() bool }
I added comments to all of the implementations to indicate
whether they will be required if net.Error.Temporary is ever
ever removed in the future.
For HandshakeError, the Temporary() return value is actually
important. I moved & rewrote a (previously misplaced) comment
there.
The ReadStreamError changes were
1. necessary to pacify newer staticcheck and
2. technically, an error can implement Temporary()
without being net.Err. This applies to some syscall
errors in the standard library.
Reading list for those interested:
- https://github.com/golang/go/issues/45729
- https://groups.google.com/g/golang-nuts/c/-JcZzOkyqYI
- https://man7.org/linux/man-pages/man2/accept.2.html
Note: This change was prompted by staticheck:
> SA1019: neterr.Temporary has been deprecated since Go 1.18 because it
> shouldn't be used: Temporary errors are not well-defined. Most
> "temporary" errors are timeouts, and the few exceptions are surprising.
> Do not use this method. (staticcheck)
* Add Close() in closeState to identify the first closer
* Non-first closers get an error
* Reads and Writes from the Conn get an error if the conn was closed
during the Read / Write was running
* The first closer starts _separate_ goroutine draining the c.frameReads channel
* The first closer then waits for the goroutine that fills c.frameReads
to exit
refs 3bfe0c16d0fixes#174
readFrames would block on `reads <-`
but only after that would stream.Conn.readFrames close c.waitReadFramesDone
which was too late because stream.Conn.Close would wait for c.waitReadFramesDone to be closed before draining the channel
^^^^^^ (not frameconn.Conn, that closed successfully)
195 @ 0x1032ae0 0x1006cab 0x1006c81 0x1006a65 0x15505be 0x155163e 0x1060bc1
0x15505bd github.com/zrepl/zrepl/rpc/dataconn/stream.readFrames+0x16d github.com/zrepl/zrepl/rpc/dataconn/stream/stream.go:220
0x155163d github.com/zrepl/zrepl/rpc/dataconn/stream.(*Conn).readFrames+0xbd github.com/zrepl/zrepl/rpc/dataconn/stream/stream_conn.go:71
195 @ 0x1032ae0 0x10078c8 0x100789e 0x100758b 0x1552678 0x1557a4b 0x1556aec 0x1060bc1
0x1552677 github.com/zrepl/zrepl/rpc/dataconn/stream.(*Conn).Close+0x77 github.com/zrepl/zrepl/rpc/dataconn/stream/stream_conn.go:191
0x1557a4a github.com/zrepl/zrepl/rpc/dataconn.(*Server).serveConn.func1+0x5a github.com/zrepl/zrepl/rpc/dataconn/dataconn_server.go:93
0x1556aeb github.com/zrepl/zrepl/rpc/dataconn.(*Server).serveConn+0x87b github.com/zrepl/zrepl/rpc/dataconn/dataconn_server.go:176
