go/src/os/exec/exec.go, branch makepkg

os/exec: document blocking Stdin/Stdout/Stderr

2026-01-27T20:28:35Z

WaitDelay only handles writes to Stdin and reads from Stdout/Stderr. If Stdin is set to a blocking Reader, or Stdout/Stderr are set to a blocking Writer, Wait can hang indefinitely. I don't see any way to fix this with the current API, as there is no general way that the os/exec package can interrupt the blocking Read or Write. This CL documents the limitation and points people toward the workaround of using StdinPipe/StdoutPipe/StderrPipe and arranging for their own way to interrupt the blocking Read or Write. Fixes #77227 Change-Id: I3150ae7af89dccf8d859b41eb43eaf0bbbb55fee Reviewed-on: https://go-review.googlesource.com/c/go/+/739422 Reviewed-by: Dmitri Shuralyov Auto-Submit: Ian Lance Taylor Reviewed-by: Sean Liao LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee

os/exec: avoid atomic.Bool for Cmd.startCalled

2026-01-06T20:26:39Z

An atomic.Bool isn't necessary here since, unless otherwise specified, the methods of an object are not concurrency-safe w.r.t. each other. Using an atomic causes the copylocks vet check to warn about copying of Cmd, which is not wrong, because one shouldn't be copying opaque complex structs from other packages, but it is a nuisance in the absence of any safe way to copy a Cmd. If and when we add a Clone method to Cmd (see #77075) then it would be appropriate to revert this change so that we get the benefit of the static check (though ideally we would make a more explicit tool-readable declaration of the "do not copy" attribute than merely happening to use an atomic.Bool). For #77075 Change-Id: I982d4e86623ca165a3e76bbf648fd44041d5f6bb Reviewed-on: https://go-review.googlesource.com/c/go/+/734200 Reviewed-by: Michael Pratt LUCI-TryBot-Result: Go LUCI

os/exec: second call to Cmd.Start is always an error

2025-12-22T18:43:07Z

Previously it would return an error only if the first call resulted in process creation, contra the intent of the comment at exec.Cmd: // A Cmd cannot be reused after calling its [Cmd.Start], [Cmd.Run], // [Cmd.Output], or [Cmd.CombinedOutput] methods. Also, clear the Cmd.goroutines slice in case of failure to start a process, so that the closures can be GC'd and their pipe fds finalized and closed. Fixes #76746 Change-Id: Ic63a4dced0aa52c2d4be7d44f6dcfc84ee22282c Reviewed-on: https://go-review.googlesource.com/c/go/+/728642 LUCI-TryBot-Result: Go LUCI Reviewed-by: Damien Neil

os/exec: include Cmd.Start in the list of methods that run Cmd

2025-11-12T15:27:58Z

Fixes #76265 Change-Id: I451271c5662dd3bcdeec07b55761b15f64c00dcd Reviewed-on: https://go-review.googlesource.com/c/go/+/719860 Reviewed-by: Keith Randall Reviewed-by: Alan Donovan Auto-Submit: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-by: Keith Randall

os/exec: fix incorrect expansion of "", "." and ".." in LookPath

2025-07-29T20:53:57Z

Fix incorrect expansion of "" and "." when $PATH contains an executable file or, on Windows, a parent directory of a %PATH% element contains an file with the same name as the %PATH% element but with one of the %PATHEXT% extension (ex: C:\utils\bin is in PATH, and C:\utils\bin.exe exists). Fix incorrect expansion of ".." when $PATH contains an element which is an the concatenation of the path to an executable file (or on Windows a path that can be expanded to an executable by appending a %PATHEXT% extension), a path separator and a name. "", "." and ".." are now rejected early with ErrNotFound. Fixes CVE-2025-47906 Fixes #74466 Change-Id: Ie50cc0a660fce8fbdc952a7f2e05c36062dcb50e Reviewed-on: https://go-review.googlesource.com/c/go/+/685755 LUCI-TryBot-Result: Go LUCI Auto-Submit: Damien Neil Reviewed-by: Roland Shoemaker Reviewed-by: Damien Neil

all: replace a few user-visible mentions of golang.org and godoc.org

2025-06-13T06:27:10Z

This change replaces a few user-visible mentions of golang.org and godoc.org with go.dev and pkg.go.dev, respectively. Non-user-visible mentions (e.g. in test scripts) were left untouched. Change-Id: I5d828edcd618b6c55243d0dfcadc6fa1ce9422ce Reviewed-on: https://go-review.googlesource.com/c/go/+/681255 Reviewed-by: Cherry Mui Reviewed-by: Dmitri Shuralyov LUCI-TryBot-Result: Go LUCI Reviewed-by: Dmitri Shuralyov

os/exec: edit comment to remove invalid link

2024-11-27T15:22:17Z

Update comment to remove link formatting that doesn't turn into a link, because the target field is not a top-level member of the package. Re-word comment slightly. Change-Id: I43ebd8fb105b772a4362c0c763e6464321a92747 Reviewed-on: https://go-review.googlesource.com/c/go/+/631856 Reviewed-by: Veronica Silina Reviewed-by: Ian Lance Taylor Auto-Submit: Ian Lance Taylor LUCI-TryBot-Result: Go LUCI

os/exec: document interaction of Dir, PWD, os.Getwd and C

2024-08-29T18:03:48Z

Fixes #68000 Change-Id: Ie70a8ecc9573b2a4cf57119bda57e0af5e16c42f Reviewed-on: https://go-review.googlesource.com/c/go/+/609395 LUCI-TryBot-Result: Go LUCI Reviewed-by: Ian Lance Taylor

os/exec: only use cachedLookExtensions if Cmd.Path is unmodified

2024-07-07T16:40:57Z

Caching the invocation of lookExtensions on an absolute path in Command and reusing the cached result in Start is only viable if Cmd.Path isn't set to a different value after Command returns. For #66586. Fixes #68314. Change-Id: I57007850aca2011b11344180c00faded737617b5 Reviewed-on: https://go-review.googlesource.com/c/go/+/596875 Reviewed-by: qiu laidongfeng2 <2645477756@qq.com> Reviewed-by: Ian Lance Taylor Auto-Submit: Dmitri Shuralyov LUCI-TryBot-Result: Go LUCI Reviewed-by: Dmitri Shuralyov

os/exec: on Windows look for extensions in Run if not already done

2024-06-07T20:13:53Z

CL 512155 fixed #36768, but introduced #62596. CL 527820 fixed #62596, but meant that the code failed to look up file extensions on Windows for a relative path. This CL fixes that problem by recording whether it has already looked up file extensions. This does mean that if Path is set manually then we do not update it with file extensions, as doing that would be racy. Fixes #66586 Change-Id: I9a0305d1e466c5e07bfbe442566ea12f5255a96e GitHub-Last-Rev: dc3169f2350f61acac5ef7842b7514013abacbe1 GitHub-Pull-Request: golang/go#67035 Reviewed-on: https://go-review.googlesource.com/c/go/+/581695 LUCI-TryBot-Result: Go LUCI Auto-Submit: Ian Lance Taylor Reviewed-by: Michael Knyszek Reviewed-by: Ian Lance Taylor