Issue #32 disable subshells by default in bash-preexec

- This is causing newer versions of bash to exit under some conditions.
  Believe this is caused by a bug in bash's debug trap and functrace that is
  being exposred by bash-preexec.

bashhub/shell/bashhub.sh

@@ -25,6 +25,9 @@ __bh_setup_bashhub() {
 
         # Pull in our libs
         source "$BH_DEPS_DIRECTORY/lib-bashhub.sh"
+
+        # Disable subshells in bash-preexec
+        export __bp_disable_subshells="true"
         source "$BH_DEPS_DIRECTORY/bash-preexec.sh"
 
         # Hook bashhub into preexec and precmd.

bashhub/shell/deps/bash-preexec.sh

@@ -11,7 +11,7 @@
 # Author: Ryan Caloras ([email protected])
 # Forked from Original Author: Glyph Lefkowitz
 #
-# V0.3.0
+# V0.3.1
 #
 
 # General Usage:
@@ -42,7 +42,7 @@ __bp_imported="defined"
 
 # Should be available to each precmd and preexec
 # functions, should they want it.
-__bp_last_command_ret_value="$?"
+__bp_last_ret_value="$?"
 
 # Command to set our preexec trap. It's invoked once via
 # PROMPT_COMMAND and then removed.
@@ -87,7 +87,7 @@ __bp_interactive_mode() {
 # It will invoke any functions defined in the precmd_functions array.
 __bp_precmd_invoke_cmd() {
 
-    # Should be available to each precmd function, should it want it.
+    # Save the returned value from our last command
     __bp_last_ret_value="$?"
 
     # For every function defined in our function array. Invoke it.
@@ -234,9 +234,17 @@ __bp_install() {
     # Adjust our HISTCONTROL Variable if needed.
     __bp_adjust_histcontrol
 
-    # Set so debug trap will work be invoked in subshells.
-    set -o functrace > /dev/null 2>&1
-    shopt -s extdebug > /dev/null 2>&1
+
+    # Issue #25. Setting debug trap for subshells causes sessions to exit for
+    # backgrounded subshell commands (e.g. (pwd)& ). Believe this is a bug in Bash.
+    #
+    # This option allows you to disable subshells.
+    if [[ -z "$__bp_disable_subshells" ]]; then
+
+        # Set so debug trap will work be invoked in subshells.
+        set -o functrace > /dev/null 2>&1
+        shopt -s extdebug > /dev/null 2>&1
+    fi;
 
 
     local existing_prompt_command

bashhub/shell/deps/lib-bashhub.sh

@@ -113,7 +113,7 @@ __bh_process_command() {
 __bh_check_bashhub_installation() {
     local ret
     ret=0
-    if [[ -n "$BASH_VERSION" && "$(trap)" != *"__bp_preexec_invoke_exec"* ]]; then
+    if [[ -n "$BASH_VERSION" && -z "$__bp_disable_subshells" && "$(trap)" != *"__bp_preexec_invoke_exec"* ]]; then
         echo "Bashhub's preexec hook is being overriden and is not saving commands. Please resolve what may be holding the DEBUG trap."
         ret=1
     elif [[ ! -f "$BH_HOME_DIRECTORY/config" ]]; then