Preserve exit status across bash prompt hooks

.github/workflows/ci.yml

@@ -271,6 +271,9 @@ jobs:
       - name: Validate bash prompt bootstrap composes with user PROMPT_COMMAND (starship)
         run: python3 tests/test_issue_5164_starship_prompt_composition.py
 
+      - name: Validate bash prompt hooks preserve command status
+        run: ./tests/test_issue_5389_bash_prompt_status.sh
+
       - name: Validate feature flags (naming, owners, expiry, single use, no reuse)
         run: python3 scripts/lint-feature-flags.py
 

Resources/shell-integration/cmux-bash-integration.bash

@@ -1607,13 +1607,15 @@ _cmux_bash_preexec_hook_subshell() {
 }
 
 _cmux_prompt_command() {
+    # This must stay the first command: every return path preserves the user's
+    # exit status for downstream PROMPT_COMMAND hooks.
     local last_status=$?
     _cmux_tmux_sync_cmux_environment
 
     local cmux_has_unix_socket=0
     _cmux_socket_is_unix && cmux_has_unix_socket=1
-    (( cmux_has_unix_socket )) || _cmux_has_port_scan_transport || return 0
-    [[ -n "$CMUX_TAB_ID" ]] || return 0
+    (( cmux_has_unix_socket )) || _cmux_has_port_scan_transport || return "$last_status"
+    [[ -n "$CMUX_TAB_ID" ]] || return "$last_status"
 
     if [[ -z "$_CMUX_TTY_NAME" ]]; then
         local t
@@ -1638,7 +1640,7 @@ _cmux_prompt_command() {
             _cmux_report_pwd_via_relay "$pwd" && _CMUX_PWD_LAST_PWD="$pwd"
         fi
     else
-        [[ -n "$CMUX_PANEL_ID" ]] || return 0
+        [[ -n "$CMUX_PANEL_ID" ]] || return "$last_status"
     fi
 
     _cmux_set_git_active_pwd "$pwd"
@@ -1752,6 +1754,7 @@ _cmux_prompt_command() {
     if (( now - _CMUX_PORTS_LAST_RUN >= 10 )); then
         _cmux_ports_kick refresh
     fi
+    return "$last_status"
 }
 
 _cmux_install_prompt_command() {

tests/test_issue_5389_bash_prompt_status.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+repo_root="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)"
+
+# Source the production integration in an isolated, transport-free shell. The
+# prompt hook should preserve the failed command's status even on this early
+# return path so the next PROMPT_COMMAND entry can observe it.
+CMUX_SOCKET_PATH=""
+CMUX_TAB_ID="tab-test"
+CMUX_PANEL_ID="panel-test"
+TMUX=""
+PROMPT_COMMAND=""
+source "$repo_root/Resources/shell-integration/cmux-bash-integration.bash"
+
+_cmux_test_cleanup() {
+    [[ -n "${_CMUX_GIT_ACTIVE_PWD_FILE:-}" ]] \
+        && /bin/rm -f -- "$_CMUX_GIT_ACTIVE_PWD_FILE" >/dev/null 2>&1 \
+        || true
+}
+trap _cmux_test_cleanup EXIT
+
+# Never let this isolated test publish its fake cmux IDs to a real tmux server.
+_cmux_tmux_sync_cmux_environment() { :; }
+
+_cmux_status_observer() {
+    printf '%s\n' "$?"
+}
+
+_assert_prompt_status_preserved() {
+    local route="$1"
+    local prompt_form="$2"
+    local observed=""
+
+    unset PROMPT_COMMAND
+    if [[ "$prompt_form" == "array" ]]; then
+        PROMPT_COMMAND=("_cmux_prompt_command" "_cmux_status_observer")
+        observed="$(
+            set +e
+            false
+            eval "${PROMPT_COMMAND[0]}"
+            eval "${PROMPT_COMMAND[1]}"
+        )"
+    else
+        PROMPT_COMMAND="_cmux_prompt_command;_cmux_status_observer"
+        observed="$(
+            set +e
+            false
+            eval "$PROMPT_COMMAND"
+        )"
+    fi
+
+    if [[ "$observed" != "1" ]]; then
+        printf 'FAIL: %s (%s) downstream hook observed status %q, expected 1\n' \
+            "$route" "$prompt_form" "$observed" >&2
+        exit 1
+    fi
+}
+
+_assert_route_preserves_status() {
+    local route="$1"
+    _assert_prompt_status_preserved "$route" string
+    _assert_prompt_status_preserved "$route" array
+}
+
+# Exercise the first early return with the production transport checks.
+_assert_route_preserves_status "no transport"
+
+# Stub only the integration's external effects so the remaining cases can
+# deterministically drive every other return path without a live cmux process.
+_cmux_socket_is_unix() { return 0; }
+_cmux_report_tty_once() { :; }
+_cmux_report_shell_activity_state() { :; }
+_cmux_reset_terminal_keyboard_protocols() { :; }
+_cmux_set_git_active_pwd() { :; }
+_cmux_stop_pr_poll_loop() { :; }
+_cmux_clear_pr_command_hint_file() { :; }
+_cmux_ports_kick() { :; }
+_cmux_send_bg() { :; }
+
+CMUX_TAB_ID=""
+_assert_route_preserves_status "missing tab"
+
+CMUX_TAB_ID="tab-test"
+CMUX_PANEL_ID=""
+_CMUX_TTY_NAME="tty-test"
+_assert_route_preserves_status "missing panel"
+
+CMUX_PANEL_ID="panel-test"
+CMUX_NO_GIT_WATCH=1
+_CMUX_PWD_LAST_PWD="$PWD"
+_assert_route_preserves_status "normal completion"
+
+printf 'PASS: downstream prompt hooks preserved status across all routes and forms\n'