Support the array PROMPT_COMMAND in Bash 5.1+

Author: akinomyoga

bash-preexec.sh

@@ -183,8 +183,8 @@ __bp_set_ret_value() {
 
 __bp_in_prompt_command() {
 
-    local prompt_command_array
-    IFS=$'\n;' read -rd '' -a prompt_command_array <<< "${PROMPT_COMMAND:-}"
+    local prompt_command_array IFS=$'\n;'
+    read -rd '' -a prompt_command_array <<< "${PROMPT_COMMAND[*]:-}"
 
     local trimmed_arg
     __bp_trim_whitespace trimmed_arg "${1:-}"
@@ -290,7 +290,7 @@ __bp_preexec_invoke_exec() {
 
 __bp_install() {
     # Exit if we already have this installed.
-    if [[ "${PROMPT_COMMAND:-}" == *"__bp_precmd_invoke_cmd"* ]]; then
+    if [[ "${PROMPT_COMMAND[*]:-}" == *"__bp_precmd_invoke_cmd"* ]]; then
         return 1;
     fi
 
@@ -332,11 +332,14 @@ __bp_install() {
 
     # Install our hooks in PROMPT_COMMAND to allow our trap to know when we've
     # actually entered something.
-    PROMPT_COMMAND=$'__bp_precmd_invoke_cmd\n'
-    if [[ -n "$existing_prompt_command" ]]; then
-        PROMPT_COMMAND+=${existing_prompt_command}$'\n'
-    fi;
-    PROMPT_COMMAND+='__bp_interactive_mode'
+    PROMPT_COMMAND='__bp_precmd_invoke_cmd'
+    PROMPT_COMMAND+=${existing_prompt_command:+$'\n'$existing_prompt_command}
+    if ((BASH_VERSINFO[0] > 5 || BASH_VERSINFO[0] == 5 && BASH_VERSINFO[1] >= 1)); then
+        PROMPT_COMMAND+=('__bp_interactive_mode')
+    else
+        # shellcheck disable=SC2179 # PROMPT_COMMAND is not an array in bash <= 5.0
+        PROMPT_COMMAND+=$'\n__bp_interactive_mode'
+    fi
 
     # Add two functions to our arrays for convenience
     # of definition.
@@ -359,8 +362,10 @@ __bp_install_after_session_init() {
     local sanitized_prompt_command
     __bp_sanitize_string sanitized_prompt_command "${PROMPT_COMMAND:-}"
     if [[ -n "$sanitized_prompt_command" ]]; then
+        # shellcheck disable=SC2178 # PROMPT_COMMAND is not an array in bash <= 5.0
         PROMPT_COMMAND=${sanitized_prompt_command}$'\n'
     fi;
+    # shellcheck disable=SC2179 # PROMPT_COMMAND is not an array in bash <= 5.0
     PROMPT_COMMAND+=${__bp_install_string}
 }
 

test/bash-preexec.bats

@@ -8,9 +8,23 @@ setup() {
   source "${BATS_TEST_DIRNAME}/../bash-preexec.sh"
 }
 
+# Evaluates all the elements of PROMPT_COMMAND
+eval_PROMPT_COMMAND() {
+  local prompt_command
+  for prompt_command in "${PROMPT_COMMAND[@]}"; do
+    eval "$prompt_command"
+  done
+}
+
+# Joins the elements of PROMPT_COMMAND with $'\n'
+join_PROMPT_COMMAND() {
+  local IFS=$'\n'
+  echo "${PROMPT_COMMAND[*]}"
+}
+
 bp_install() {
   __bp_install_after_session_init
-  eval "$PROMPT_COMMAND"
+  eval_PROMPT_COMMAND
 }
 
 test_echo() {
@@ -63,7 +77,7 @@ set_exit_code_and_run_precmd() {
   [[ "$PROMPT_COMMAND" == *"trap - DEBUG"* ]] || return 1
   [[ "$PROMPT_COMMAND" == *"__bp_install"* ]] || return 1
 
-  eval "$PROMPT_COMMAND"
+  eval_PROMPT_COMMAND
 
   [[ "$PROMPT_COMMAND" != *"trap DEBUG"* ]] || return 1
   [[ "$PROMPT_COMMAND" != *"__bp_install"* ]] || return 1
@@ -106,7 +120,7 @@ set_exit_code_and_run_precmd() {
     bp_install
 
     PROMPT_COMMAND="$PROMPT_COMMAND; true"
-    eval "$PROMPT_COMMAND"
+    eval_PROMPT_COMMAND
 }
 
 @test "Appending or prepending to PROMPT_COMMAND should work after bp_install_after_session_init" {
@@ -119,7 +133,7 @@ set_exit_code_and_run_precmd() {
     PROMPT_COMMAND="true; $PROMPT_COMMAND"
     PROMPT_COMMAND="true; $PROMPT_COMMAND"
     PROMPT_COMMAND="true $nl $PROMPT_COMMAND"
-    eval "$PROMPT_COMMAND"
+    eval_PROMPT_COMMAND
 }
 
 # Case where a user is appending or prepending to PROMPT_COMMAND.
@@ -132,21 +146,21 @@ set_exit_code_and_run_precmd() {
     PROMPT_COMMAND="$PROMPT_COMMAND"$'\n echo after'
     PROMPT_COMMAND="echo after2; $PROMPT_COMMAND;"
 
-    eval "$PROMPT_COMMAND"
+    eval_PROMPT_COMMAND
 
     expected_result=$'__bp_precmd_invoke_cmd\necho after2; echo before; echo before2\n echo after\n__bp_interactive_mode'
-    [ "$PROMPT_COMMAND" == "$expected_result" ]
+    [ "$(join_PROMPT_COMMAND)" == "$expected_result" ]
 }
 
 @test "Adding to PROMPT_COMMAND after with semicolon" {
     PROMPT_COMMAND="echo before"
     __bp_install_after_session_init
     PROMPT_COMMAND="$PROMPT_COMMAND; echo after"
 
-    eval "$PROMPT_COMMAND"
+    eval_PROMPT_COMMAND
 
     expected_result=$'__bp_precmd_invoke_cmd\necho before\n echo after\n__bp_interactive_mode'
-    [ "$PROMPT_COMMAND" == "$expected_result" ]
+    [ "$(join_PROMPT_COMMAND)" == "$expected_result" ]
 }
 
 @test "during install PROMPT_COMMAND and precmd functions should be executed each once" {
@@ -157,7 +171,7 @@ set_exit_code_and_run_precmd() {
     PROMPT_COMMAND="echo after2; $PROMPT_COMMAND;"
 
     precmd() { echo "inside precmd"; }
-    run eval "$PROMPT_COMMAND"
+    run eval_PROMPT_COMMAND
     [ "${lines[0]}" == "after2" ]
     [ "${lines[1]}" == "before" ]
     [ "${lines[2]}" == "before2" ]