go/src/testing/synctest/synctest.go, branch fix-runtime-test-GOMAXPROCS

synctest: fix comments for time.Now() in synctests

2025-07-10T20:16:07Z

Also add a test case to make sure that time.Now() results in the documented date. Change-Id: Ic4cc577eba485b7c6e1a64122da06d7075bbe12e Reviewed-on: https://go-review.googlesource.com/c/go/+/685677 LUCI-TryBot-Result: Go LUCI Auto-Submit: Christian Höppner Reviewed-by: Damien Neil

testing/synctest, runtime: avoid panic when using linker-alloc WG from bubble

2025-06-10T22:02:26Z

We associate WaitGroups with synctest bubbles by attaching a special to the WaitGroup. It is not possible to attach a special to a linker-allocated value, such as: var wg sync.WaitGroup Avoid panicking when accessing a linker-allocated WaitGroup from a bubble. We have no way to associate these WaitGroups with a bubble, so just treat them as always unbubbled. This is probably fine, since the WaitGroup was always created outside the bubble in this case. Fixes #74005 Change-Id: Ic71514b0b8d0cecd62e45cc929ffcbeb16f54a55 Reviewed-on: https://go-review.googlesource.com/c/go/+/679695 Reviewed-by: Michael Knyszek Auto-Submit: Damien Neil LUCI-TryBot-Result: Go LUCI

testing, testing/synctest: report correct duration after panics

2025-05-30T16:23:37Z

Report the correct wall-clock test duration after handling a panic in a synctest.Test bubble. Fixes #73852 Change-Id: I053262e5eac2dd9d5938b17c3093cbc3fa115a0d Reviewed-on: https://go-review.googlesource.com/c/go/+/676695 Auto-Submit: Damien Neil Reviewed-by: Alan Donovan LUCI-TryBot-Result: Go LUCI

runtime, testing/synctest: breaking bubble isolation with Cond is fatal

2025-05-29T19:49:36Z

sync.Cond.Wait is durably blocking. Waking a goroutine out of Cond.Wait from outside its bubble panics. Make this panic a fatal panic, since it leaves the notifyList in an inconsistent state. We could do some work to make this a recoverable panic, but the complexity doesn't seem worth the outcome. For #67434 Change-Id: I88874c1519c2e5c0063175297a9b120cedabcd07 Reviewed-on: https://go-review.googlesource.com/c/go/+/675617 LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Pratt Auto-Submit: Damien Neil

runtime, internal/synctest, sync: associate WaitGroups with bubbles

2025-05-29T17:26:00Z

Add support to internal/synctest for managing associations between arbitrary pointers and synctest bubbles. (Implemented internally to the runtime package by attaching a special to the pointer.) Associate WaitGroups with bubbles. Since WaitGroups don't have a constructor, perform the association when Add is called. All Add calls must be made from within the same bubble, or outside any bubble. When a bubbled goroutine calls WaitGroup.Wait, the wait is durably blocking iff the WaitGroup is associated with the current bubble. Change-Id: I77e2701e734ac2fa2b32b28d5b0c853b7b2825c9 Reviewed-on: https://go-review.googlesource.com/c/go/+/676656 Reviewed-by: Michael Knyszek Reviewed-by: Michael Pratt LUCI-TryBot-Result: Go LUCI Auto-Submit: Damien Neil

runtime, testing/synctest: verify cleanups/finalizers run outside bubbles

2025-05-27T21:47:13Z

Cleanup functions and finalizers must not run in a synctest bubble. If they did, a function run by the GC at an unpredictable time could unblock a bubble that synctest believes is durably blocked. Add a test verifying that cleanups and finalizers are always run by non-bubbled goroutines. (This is already the case because we never add system goroutines to a bubble.) For #67434 Change-Id: I5a48db2b26f9712c3b0dc1f425d99814031a2fc1 Reviewed-on: https://go-review.googlesource.com/c/go/+/675257 Reviewed-by: Michael Pratt LUCI-TryBot-Result: Go LUCI Auto-Submit: Damien Neil

testing/synctest: correct duration in doc example

2025-05-24T15:42:04Z

Fixes #73839 Change-Id: I961641c6d8244cdeb101a3c9ae91931828a893ad Reviewed-on: https://go-review.googlesource.com/c/go/+/676035 LUCI-TryBot-Result: Go LUCI Reviewed-by: Dmitri Shuralyov Reviewed-by: Alan Donovan

testing/synctest: add Test

2025-05-20T22:46:03Z

Add a synctest.Test function, superseding the experimental synctest.Run function. Promote the testing/synctest package out of experimental status. For #67434 For #73567 Change-Id: I3c5ba030860d90fe2ddb517a2f3536efd60181a9 Reviewed-on: https://go-review.googlesource.com/c/go/+/671961 Auto-Submit: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Pratt

runtime, testing/synctest: stop advancing time when main goroutine exits

2025-05-07T20:14:25Z

Once the goroutine started by synctest.Run exits, stop advancing the fake clock in its bubble. This avoids confusing situations where a bubble remains alive indefinitely while a background goroutine reads from a time.Ticker or otherwise advances the clock. For #67434 Change-Id: Id608ffe3c7d7b07747b56a21f365787fb9a057d7 Reviewed-on: https://go-review.googlesource.com/c/go/+/662155 Reviewed-by: Michael Pratt LUCI-TryBot-Result: Go LUCI Auto-Submit: Damien Neil

testing/synctest: add experimental synctest package

2024-11-20T16:26:46Z

The testing/synctest package is experimental, subject to change or removal, and only present when GOEXPERIMENT=synctest. Fixes #69687 Change-Id: I6c79e7d1479a54bebcd2de754854c87bfd0a5fa1 Reviewed-on: https://go-review.googlesource.com/c/go/+/629735 Reviewed-by: Michael Pratt LUCI-TryBot-Result: Go LUCI