Abstract task command over *exec.Cmd

Windows ConPTY can't attach a child process to a pseudoconsole via
os/exec — Go's stdlib doesn't expose PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE
(golang/go#62708). The ConPTY path has to call CreateProcess directly,
so it can't hand an *exec.Cmd back to the task runner.

Widen NewCmdTask to accept a small Cmd interface satisfied by both
*exec.Cmd (via the ExecCmd adapter) and the Windows ConPTY command type
we're about to add. Change TerminateProcessGracefully to take
*os.Process, which both cmd shapes can provide.

Behavior is unchanged on every platform.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pkg/commands/oscommands/os_default_platform.go

@@ -4,7 +4,6 @@ package oscommands
 
 import (
 	"os"
-	"os/exec"
 	"runtime"
 	"strings"
 	"syscall"
@@ -40,10 +39,10 @@ func (c *OSCommand) UpdateWindowTitle() error {
 	return nil
 }
 
-func TerminateProcessGracefully(cmd *exec.Cmd) error {
-	if cmd.Process == nil {
+func TerminateProcessGracefully(proc *os.Process) error {
+	if proc == nil {
 		return nil
 	}
 
-	return cmd.Process.Signal(syscall.SIGTERM)
+	return proc.Signal(syscall.SIGTERM)
 }

pkg/commands/oscommands/os_windows.go

@@ -3,7 +3,6 @@ package oscommands
 import (
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 )
 
@@ -24,7 +23,7 @@ func (c *OSCommand) UpdateWindowTitle() error {
 	return c.Cmd.NewShell(argString, c.UserConfig().OS.ShellFunctionsFile).Run()
 }
 
-func TerminateProcessGracefully(cmd *exec.Cmd) error {
+func TerminateProcessGracefully(proc *os.Process) error {
 	// Signals other than SIGKILL are not supported on Windows
 	return nil
 }

pkg/gui/pty.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/creack/pty"
 	"github.com/jesseduffield/lazygit/pkg/gocui"
+	"github.com/jesseduffield/lazygit/pkg/tasks"
 	"github.com/jesseduffield/lazygit/pkg/utils"
 	"github.com/samber/lo"
 )
@@ -75,7 +76,7 @@ func (gui *Gui) newPtyTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 		manager := gui.getManager(view)
 
 		var ptmx *os.File
-		start := func() (*exec.Cmd, io.Reader) {
+		start := func() (tasks.Cmd, io.Reader) {
 			var err error
 			ptmx, err = pty.StartWithSize(cmd, gui.desiredPtySize(view))
 			if err != nil {
@@ -86,7 +87,7 @@ func (gui *Gui) newPtyTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 			gui.viewPtmxMap[view.Name()] = ptmx
 			gui.Mutexes.PtyMutex.Unlock()
 
-			return cmd, ptmx
+			return tasks.ExecCmd{Cmd: cmd}, ptmx
 		}
 
 		onClose := func() {

pkg/gui/tasks_adapter.go

@@ -19,7 +19,7 @@ func (gui *Gui) newCmdTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 	manager := gui.getManager(view)
 
 	var r io.ReadCloser
-	start := func() (*exec.Cmd, io.Reader) {
+	start := func() (tasks.Cmd, io.Reader) {
 		var err error
 		r, err = cmd.StdoutPipe()
 		if err != nil {
@@ -32,7 +32,7 @@ func (gui *Gui) newCmdTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 			gui.c.Log.Error(err)
 		}
 
-		return cmd, r
+		return tasks.ExecCmd{Cmd: cmd}, r
 	}
 
 	onClose := func() {

pkg/tasks/tasks.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"os"
 	"os/exec"
 	"sync"
 	"time"
@@ -15,6 +16,25 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// Cmd abstracts over a started external process. *exec.Cmd satisfies the bulk
+// of it via ExecCmd, but pty implementations can supply their own types — on
+// Windows, ConPTY has to spawn via CreateProcess directly and can't use
+// *exec.Cmd (see golang/go#62708).
+type Cmd interface {
+	Wait() error
+	String() string
+	GetProcess() *os.Process
+}
+
+// ExecCmd adapts *exec.Cmd to Cmd.
+type ExecCmd struct {
+	*exec.Cmd
+}
+
+func (c ExecCmd) GetProcess() *os.Process {
+	return c.Process
+}
+
 // This file revolves around running commands that will be output to the main panel
 // in the gui. If we're flicking through the commits panel, we want to invoke a
 // `git show` command for each commit, but we don't want to read the entire output
@@ -117,7 +137,7 @@ func (self *ViewBufferManager) ReadToEnd(then func()) {
 	}
 }
 
-func (self *ViewBufferManager) NewCmdTask(start func() (*exec.Cmd, io.Reader), prefix string, linesToRead LinesToRead, onDoneFn func()) func(TaskOpts) error {
+func (self *ViewBufferManager) NewCmdTask(start func() (Cmd, io.Reader), prefix string, linesToRead LinesToRead, onDoneFn func()) func(TaskOpts) error {
 	return func(opts TaskOpts) error {
 		var onDoneOnce sync.Once
 		var onFirstPageShownOnce sync.Once
@@ -173,8 +193,8 @@ func (self *ViewBufferManager) NewCmdTask(start func() (*exec.Cmd, io.Reader), p
 				//
 				// Unfortunately this will do nothing on Windows, so Windows users will have to live
 				// with the higher CPU usage.
-				if err := oscommands.TerminateProcessGracefully(cmd); err != nil {
-					self.Log.Errorf("error when trying to terminate cmd task: %v; Command: %v %v", err, cmd.Path, cmd.Args)
+				if err := oscommands.TerminateProcessGracefully(cmd.GetProcess()); err != nil {
+					self.Log.Errorf("error when trying to terminate cmd task: %v; Command: %v", err, cmd.String())
 				}
 
 				// close the task's stdout pipe (or the pty if we're using one) to make the command terminate
@@ -316,7 +336,7 @@ func (self *ViewBufferManager) NewCmdTask(start func() (*exec.Cmd, io.Reader), p
 				go func() { _ = cmd.Wait() }()
 			default:
 				if err := cmd.Wait(); err != nil {
-					self.Log.Errorf("Unexpected error when running cmd task: %v; Failed command: %v %v", err, cmd.Path, cmd.Args)
+					self.Log.Errorf("Unexpected error when running cmd task: %v; Failed command: %v", err, cmd.String())
 				}
 			}
 

pkg/tasks/tasks_test.go

@@ -43,13 +43,13 @@ func TestNewCmdTaskInstantStop(t *testing.T) {
 
 	stop := make(chan struct{})
 	reader := bytes.NewBufferString("test")
-	start := func() (*exec.Cmd, io.Reader) {
+	start := func() (Cmd, io.Reader) {
 		// not actually starting this because it's not necessary
 		cmd := exec.Command("blah")
 
 		close(stop)
 
-		return cmd, reader
+		return ExecCmd{Cmd: cmd}, reader
 	}
 
 	fn := manager.NewCmdTask(start, "prefix\n", LinesToRead{20, -1, nil}, onDone)
@@ -108,11 +108,11 @@ func TestNewCmdTask(t *testing.T) {
 
 	stop := make(chan struct{})
 	reader := bytes.NewBufferString("test")
-	start := func() (*exec.Cmd, io.Reader) {
+	start := func() (Cmd, io.Reader) {
 		// not actually starting this because it's not necessary
 		cmd := exec.Command("blah")
 
-		return cmd, reader
+		return ExecCmd{Cmd: cmd}, reader
 	}
 
 	fn := manager.NewCmdTask(start, "prefix\n", LinesToRead{20, -1, nil}, onDone)
@@ -241,11 +241,11 @@ func TestNewCmdTaskRefresh(t *testing.T) {
 
 		stop := make(chan struct{})
 		reader := BlankLineReader{totalLinesToYield: s.totalTaskLines}
-		start := func() (*exec.Cmd, io.Reader) {
+		start := func() (Cmd, io.Reader) {
 			// not actually starting this because it's not necessary
 			cmd := exec.Command("blah")
 
-			return cmd, &reader
+			return ExecCmd{Cmd: cmd}, &reader
 		}
 
 		fn := manager.NewCmdTask(start, "", s.linesToRead, func() {})