Fix condition where pre-exec hooks would not trigger

bash-preexec.sh

@@ -133,6 +133,13 @@ __bp_set_ret_value() {
     return ${1:-}
 }
 
+# Sets the last command we ran. This is used to check if we're still executing
+# the same command at the next run of preexec (e.g. for `ls ; ls` we will
+# trigger through the DEBUG trap twice.
+__bp_set_last_command() {
+    __bp_last_command="$1"
+}
+
 __bp_in_prompt_command() {
 
     local prompt_command_array
@@ -180,9 +187,18 @@ __bp_preexec_invoke_exec() {
         # an interactively issued command.
         return
     fi
-    if [[ -z "${__bp_preexec_interactive_mode:-}" ]]; then
-        # We're doing something related to displaying the prompt.  Let the
-        # prompt set the title instead of me.
+
+    local this_command
+    this_command=$(
+        export LC_ALL=C
+        HISTTIMEFORMAT= builtin history 1 | sed '1 s/^ *[0-9][0-9]*[* ] //'
+    )
+
+    if [[ -z "${__bp_preexec_interactive_mode:-}" && \
+          "$this_command" != "$__bp_last_command" ]]; then
+        # We're doing something related to displaying the prompt and this
+        # isn't a follow-up to our last command, let the prompt set the
+        # title instead of me.
         return
     else
         # If we're in a subshell, then the prompt won't be re-displayed to put
@@ -202,12 +218,6 @@ __bp_preexec_invoke_exec() {
         return
     fi
 
-    local this_command
-    this_command=$(
-        export LC_ALL=C
-        HISTTIMEFORMAT= builtin history 1 | sed '1 s/^ *[0-9][0-9]*[* ] //'
-    )
-
     # Sanity check to make sure we have something to invoke our function with.
     if [[ -z "$this_command" ]]; then
         return
@@ -226,6 +236,7 @@ __bp_preexec_invoke_exec() {
         # Only execute each function if it actually exists.
         # Test existence of function with: declare -[fF]
         if type -t "$preexec_function" 1>/dev/null; then
+            __bp_set_last_command "$this_command"
             __bp_set_ret_value ${__bp_last_ret_value:-}
             # Quote our function invocation to prevent issues with IFS
             "$preexec_function" "$this_command"
@@ -242,6 +253,7 @@ __bp_preexec_invoke_exec() {
     # If `extdebug` is enabled a non-zero return value from any preexec function
     # will cause the user's command not to execute.
     # Run `shopt -s extdebug` to enable
+    __bp_set_last_command "$this_command"
     __bp_set_ret_value "$preexec_ret_value" "$__bp_last_argument_prev_command"
 }
 

test/bash-preexec.bats

@@ -21,6 +21,11 @@ test_preexec_echo() {
   printf "%s\n" "$1"
 }
 
+# This function is used when you need a non-zero return, as zero is the default
+test_preexec_ret_error() {
+  return 1
+}
+
 @test "__bp_install_after_session_init should exit with 1 if we're not using bash" {
   unset BASH_VERSION
   run '__bp_install_after_session_init'
@@ -292,3 +297,21 @@ a multiline string'" ]
     [ $status -eq 0 ]
     [ "$output" == '-n' ]
 }
+
+@test "preexec should trigger when several processes are executed, from the same interactive CLI command" {
+    preexec_functions+=(test_preexec_ret_error)
+    history -s -- 'ls;ls'
+    __bp_interactive_mode
+    run '__bp_preexec_invoke_exec'
+    # __bp_interactive_mode is now set to empty string, but history still matches
+    # so we should still be running the preexec hook when the second `ls` runs.
+    run '__bp_preexec_invoke_exec'
+    [ $status -eq 1 ]
+
+    # We should now exit without running the preexec hook
+    # which results in the return defaulting to 0.
+    __bp_preexec_interactive_mode=""
+    __bp_last_command=""
+    run '__bp_preexec_invoke_exec'
+    [ $status -eq 0 ]
+}