From eae23bc9c015f63167c21849519f46d658e10b7d Mon Sep 17 00:00:00 2001
From: Pietro Di Bello <pierodibello@gmail.com>
Date: Sat, 18 Jul 2026 23:39:26 +0200
Subject: [PATCH] fix(warp): stop /dev/tty ENXIO error leaking to the user

When there's no controlling terminal (e.g. a SessionStart hook
subprocess before CLAUDE_CODE_VERSION is resolvable), the /dev/tty
write fails with ENXIO. `> /dev/tty 2>/dev/null` can't suppress bash's
own "Device not configured" diagnostic in that case: bash reports the
failed redirect before it applies the following 2>/dev/null, so the
raw error still reaches the user's terminal on session start.

Wrapping the write in a brace group before the 2>/dev/null redirect
applies the suppression to the whole group up front, so the error is
caught. Behavior (return codes, JSON fallback) is unchanged; verified
against the existing test-hooks.sh suite (57/57 passing) plus a direct
before/after repro with no controlling tty and an unset
CLAUDE_CODE_VERSION.
---
 plugins/warp/scripts/emit-terminal-sequence.sh | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/plugins/warp/scripts/emit-terminal-sequence.sh b/plugins/warp/scripts/emit-terminal-sequence.sh
index b6a83b9..80a207e 100644
--- a/plugins/warp/scripts/emit-terminal-sequence.sh
+++ b/plugins/warp/scripts/emit-terminal-sequence.sh
@@ -72,14 +72,24 @@ emit_terminal_sequence() {
             # Known-old Claude Code — /dev/tty is the only safe path.
             # Emitting terminalSequence here would be rejected by the Stop
             # hook validator as an unknown field.
-            printf '%s' "$seq" > /dev/tty 2>/dev/null || true
+            #
+            # The write is wrapped in a brace group before the redirect to
+            # /dev/null: when there's no controlling terminal, opening
+            # /dev/tty fails with ENXIO ("Device not configured") and bash
+            # reports that itself, to the *original* stderr — a bare
+            # `> /dev/tty 2>/dev/null` can't catch it because the failing
+            # redirect is set up before the `2>/dev/null` one. Grouping
+            # applies 2>/dev/null to the whole group first.
+            { printf '%s' "$seq" > /dev/tty; } 2>/dev/null || true
         fi
         return 0
     fi
 
     # Unknown Claude Code version — try /dev/tty, fall back to JSON
     # as a best-effort attempt for new CC without version detection.
-    if printf '%s' "$seq" > /dev/tty 2>/dev/null; then
+    # See the brace-group note above: it's needed here too, otherwise a
+    # missing controlling terminal leaks a raw bash error to the user.
+    if { printf '%s' "$seq" > /dev/tty; } 2>/dev/null; then
         return 0
     fi
     jq -nc --arg seq "$seq" '{terminalSequence: $seq}'