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fix(handoff): don't kill pane processes before respawn (hq-bv7ef)

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The previous approach using KillPaneProcessesExcluding/KillPaneProcesses
killed the pane's main process (Claude/node) before calling RespawnPane.
This caused the pane to close (since tmux's remain-on-exit is off by default),
which then made RespawnPane fail because the target pane no longer exists.

The respawn-pane -k flag handles killing atomically - it kills the old process
and starts the new one in a single operation without closing the pane in between.
If orphan processes remain (e.g., Claude ignoring SIGHUP), they will be cleaned
up when the new session starts or by periodic cleanup processes.

This fixes both self-handoff and remote handoff paths.

Fixes: hq-bv7ef

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
furiosa
2026-01-24 15:56:41 -08:00
committed by John Ogle
parent 43f6b63792
commit c4b74ee7bf
1 changed files with 14 additions and 37 deletions
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51
internal/cmd/handoff.go
View File

@@ -5,7 +5,6 @@ import (
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"github.com/spf13/cobra"
@@ -203,29 +202,17 @@ func runHandoff(cmd *cobra.Command, args []string) error {
_ = os.WriteFile(markerPath, []byte(currentSession), 0644)
}
// Set remain-on-exit so the pane survives process death during handoff.
// Without this, killing processes causes tmux to destroy the pane before
// we can respawn it. This is essential for tmux session reuse.
if err := t.SetRemainOnExit(pane, true); err != nil {
style.PrintWarning("could not set remain-on-exit: %v", err)
}
// Kill all processes in the pane before respawning to prevent orphan leaks.
// RespawnPane's -k flag only sends SIGHUP which Claude/Node may ignore.
// NOTE: We intentionally do NOT kill pane processes before respawning (hq-bv7ef).
// Previous approach (KillPaneProcessesExcluding) killed the pane's main process,
// which caused the pane to close (remain-on-exit is off by default), making
// RespawnPane fail because the target pane no longer exists.
//
// IMPORTANT: For self-handoff, we must exclude our own process and parent (Claude Code)
// from being killed. Otherwise gt handoff dies before reaching RespawnPane.
excludePIDs := []string{
strconv.Itoa(os.Getpid()), // gt handoff process
strconv.Itoa(os.Getppid()), // Claude Code (parent)
}
if err := t.KillPaneProcessesExcluding(pane, excludePIDs); err != nil {
// Non-fatal but log the warning
style.PrintWarning("could not kill pane processes: %v", err)
}
// The respawn-pane -k flag handles killing atomically - it kills the old process
// and starts the new one in a single operation without closing the pane.
// If orphan processes remain (e.g., Claude ignoring SIGHUP), they will be cleaned
// up when the new session starts or when the Witness runs periodic cleanup.
// Use respawn-pane -k to atomically kill current process and start new one
// Note: respawn-pane automatically resets remain-on-exit to off
// Use respawn-pane to atomically kill old process and start new one
return t.RespawnPane(pane, restartCmd)
}
@@ -581,19 +568,10 @@ func handoffRemoteSession(t *tmux.Tmux, targetSession, restartCmd string) error
return nil
}
// Set remain-on-exit so the pane survives process death during handoff.
// Without this, killing processes causes tmux to destroy the pane before
// we can respawn it. This is essential for tmux session reuse.
if err := t.SetRemainOnExit(targetPane, true); err != nil {
style.PrintWarning("could not set remain-on-exit: %v", err)
}
// Kill all processes in the pane before respawning to prevent orphan leaks
// RespawnPane's -k flag only sends SIGHUP which Claude/Node may ignore
if err := t.KillPaneProcesses(targetPane); err != nil {
// Non-fatal but log the warning
style.PrintWarning("could not kill pane processes: %v", err)
}
// NOTE: We intentionally do NOT kill pane processes before respawning (hq-bv7ef).
// Previous approach (KillPaneProcesses) killed the pane's main process, which caused
// the pane to close (remain-on-exit is off by default), making RespawnPane fail.
// The respawn-pane -k flag handles killing atomically without closing the pane.
// Clear scrollback history before respawn (resets copy-mode from [0/N] to [0/0])
if err := t.ClearHistory(targetPane); err != nil {
@@ -601,8 +579,7 @@ func handoffRemoteSession(t *tmux.Tmux, targetSession, restartCmd string) error
style.PrintWarning("could not clear history: %v", err)
}
// Respawn the remote session's pane
// Note: respawn-pane automatically resets remain-on-exit to off
// Respawn the remote session's pane - -k flag atomically kills old process and starts new one
if err := t.RespawnPane(targetPane, restartCmd); err != nil {
return fmt.Errorf("respawning pane: %w", err)
}