feat: Allow callback scripts to be implemented in any language

The original code invoked all plugin callback scripts with Bash.
While all plugin callback scripts are currently implemented in
Bash it is conceivable that another a better shell language will
emerge and become popular. I dont think mandating Bash is the
right choice anymore. I do think that for nearly all plugins
Bash is the right choice right now and for compatibility
purposes Bash should be encouraged.

lib/commands/command-help.bash

@@ -94,18 +94,18 @@ print_plugin_help() {
 
   # Eventually @jthegedus or someone else will format the output from these
   # scripts in a certain way.
-  bash "${plugin_path}"/bin/help.overview
+  "${plugin_path}"/bin/help.overview
 
   if [ -f "${plugin_path}"/bin/help.deps ]; then
-    bash "${plugin_path}"/bin/help.deps
+    "${plugin_path}"/bin/help.deps
   fi
 
   if [ -f "${plugin_path}"/bin/help.config ]; then
-    bash "${plugin_path}"/bin/help.config
+    "${plugin_path}"/bin/help.config
   fi
 
   if [ -f "${plugin_path}"/bin/help.links ]; then
-    bash "${plugin_path}"/bin/help.links
+    "${plugin_path}"/bin/help.links
   fi
 }
 

lib/commands/command-install.bash

@@ -169,7 +169,7 @@ install_tool_version() {
         export ASDF_DOWNLOAD_PATH=$download_path
         mkdir "$download_path"
         asdf_run_hook "pre_asdf_download_${plugin_name}" "$full_version"
-        bash "${plugin_path}"/bin/download
+        "${plugin_path}"/bin/download
       )
     fi
 
@@ -188,7 +188,7 @@ install_tool_version() {
         export ASDF_CONCURRENCY=$concurrency
         mkdir "$install_path"
         asdf_run_hook "pre_asdf_install_${plugin_name}" "$full_version"
-        bash "${plugin_path}"/bin/install
+        "${plugin_path}"/bin/install
       )
     fi
 

lib/commands/command-latest.bash

@@ -15,7 +15,7 @@ latest_command() {
   local versions
 
   if [ -f "${plugin_path}/bin/latest-stable" ]; then
-    versions=$(bash "${plugin_path}"/bin/latest-stable "$query")
+    versions=$("${plugin_path}"/bin/latest-stable "$query")
     if [ -z "${versions}" ]; then
       # this branch requires this print to mimic the error from the list-all branch
       printf "No compatible versions available (%s %s)\n" "$plugin_name" "$query" >&2

lib/commands/command-list-all.bash

@@ -13,7 +13,7 @@ list_all_command() {
   # Capture return code to allow error handling
   std_out_file="$(mktemp "/tmp/asdf-command-list-all-${plugin_name}.stdout.XXXXXX")"
   std_err_file="$(mktemp "/tmp/asdf-command-list-all-${plugin_name}.stderr.XXXXXX")"
-  return_code=0 && bash "${plugin_path}/bin/list-all" >"$std_out_file" 2>"$std_err_file" || return_code=$?
+  return_code=0 && "${plugin_path}/bin/list-all" >"$std_out_file" 2>"$std_err_file" || return_code=$?
 
   if [[ $return_code -ne 0 ]]; then
     # Printing all output to allow plugin to handle error formatting

lib/commands/command-plugin-add.bash

@@ -41,7 +41,7 @@ plugin_add_command() {
       (
         export ASDF_PLUGIN_SOURCE_URL=$source_url
         export ASDF_PLUGIN_PATH=$plugin_path
-        bash "${plugin_path}/bin/post-plugin-add"
+        "${plugin_path}/bin/post-plugin-add"
       )
     fi
 

lib/commands/command-plugin-remove.bash

@@ -13,7 +13,7 @@ plugin_remove_command() {
   if [ -f "${plugin_path}/bin/pre-plugin-remove" ]; then
     (
       export ASDF_PLUGIN_PATH=$plugin_path
-      bash "${plugin_path}/bin/pre-plugin-remove"
+      "${plugin_path}/bin/pre-plugin-remove"
     )
   fi
 

lib/commands/command-uninstall.bash

@@ -36,7 +36,7 @@ uninstall_command() {
       export ASDF_INSTALL_TYPE=$install_type
       export ASDF_INSTALL_VERSION=$version
       export ASDF_INSTALL_PATH=$install_path
-      bash "${plugin_path}/bin/uninstall"
+      "${plugin_path}/bin/uninstall"
     )
   else
     rm -rf "$install_path"

lib/utils.bash

@@ -198,7 +198,7 @@ find_versions() {
   local legacy_filenames=""
 
   if [ "$legacy_config" = "yes" ] && [ -f "$legacy_list_filenames_script" ]; then
-    legacy_filenames=$(bash "$legacy_list_filenames_script")
+    legacy_filenames=$($legacy_list_filenames_script)
   fi
 
   while [ "$search_path" != "/" ]; do
@@ -329,7 +329,7 @@ parse_legacy_version_file() {
 
   if [ -f "$file_path" ]; then
     if [ -f "$parse_legacy_script" ]; then
-      bash "$parse_legacy_script" "$file_path"
+      "$parse_legacy_script" "$file_path"
     else
       cat "$file_path"
     fi
@@ -481,7 +481,7 @@ list_plugin_bin_paths() {
       export ASDF_INSTALL_TYPE=$install_type
       export ASDF_INSTALL_VERSION=$version
       export ASDF_INSTALL_PATH=$install_path
-      bash "${plugin_path}/bin/list-bin-paths"
+      "${plugin_path}/bin/list-bin-paths"
     )
   else
     local space_separated_list_of_bin_paths="bin"