all: update go directive to 1.18

Done with:

go get [email protected]
go mod tidy
go fix ./...

Using go1.21.3.

While here, simplify package syncmap by taking advantage of knowing
that all supported Go versions will have the go1.9 build constraint
satisfied.

For golang/go#60268.

Change-Id: Ic0f24ab13ada6839573e55beee5516c1a6c7f3cc
Reviewed-on: https://go-review.googlesource.com/c/sync/+/534220
Auto-Submit: Dmitri Shuralyov <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

singleflight: add panicError.Unwrap method

Currently when singleflight recovers from a panic, it wraps it with the private
error type panicError. This change adds an `Unwrap` method to panicError to
allow wrapped errors to be returned.

Updates golang/go#62511

Change-Id: Ia510ad7d5881207ef71f9eb89c1766835af19b6b
Reviewed-on: https://go-review.googlesource.com/c/sync/+/526171
Auto-Submit: Bryan Mills <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

errgroup: use WithCancelCause to cancel context

Fixes golang/go#59355

Change-Id: Ib6a88e7e5fefe7b0d5672035af16d109aabcbf1e
Reviewed-on: https://go-review.googlesource.com/c/sync/+/481255
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Bryan Mills <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>

singleflight: make the check for exec support in TestPanicDoChan plat…

…form-agnostic

The new wasip1 GOOS does not support exec, but some ios environments
(like Corellium) might. Update the test to exec itself with -test.list
as a control case.

For golang/go#58141.

Change-Id: Id69950fc394910620f6c73cb437ca75c09ad8c29
Reviewed-on: https://go-review.googlesource.com/c/sync/+/485980
Run-TryBot: Bryan Mills <[email protected]>
Commit-Queue: Bryan Mills <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
Reviewed-by: Johan Brandhorst-Satzkorn <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

singleflight: avoid race between multiple Do calls

This is port of CL 436437, but without the test. ForgotUnshared has not
been ported here yet.

Change-Id: Id54d0c41d1a7948bf008e458c44b21670ada81e4
Reviewed-on: https://go-review.googlesource.com/c/sync/+/436495
Run-TryBot: Cuong Manh Le <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Cuong Manh Le <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>