path: Strip _GO_SCRIPTS_DIR from _GO_PLUGINS_PATHS

This is part of the refactoring of `_GO_USE_MODULES` to provide correct
`@go` command script scope for plugin modules.

Specifically, it allows the `@go plugins` builtin command to produce the
proper output relative to each plugin, but more generally, it makes
sense to strip a plugin's `_GO_SCRIPTS_DIR` out of its
`_GO_PLUGINS_PATHS`, rather than just stripping it from
`_GO_SEARCH_PATHS`.

Author: mbland

lib/internal/set-search-paths

@@ -2,8 +2,15 @@
 
 _@go.set_search_paths_add_plugin_paths() {
   local plugin_paths=("$1"/*/bin)
+  local plugin_path
+
   if [[ "${plugin_paths[0]}" != "$1/*/bin" ]]; then
-    _GO_PLUGINS_PATHS+=("${plugin_paths[@]}")
+    # Ensure a plugin's _GO_SCRIPTS_DIR isn't duplicated in _GO_PLUGINS_PATHS.
+    for plugin_path in "${plugin_paths[@]}"; do
+      if [[ "$plugin_path" != "$_GO_SCRIPTS_DIR" ]]; then
+        _GO_PLUGINS_PATHS+=("$plugin_path")
+      fi
+    done
   fi
   return 1
 }
@@ -20,13 +27,7 @@ _@go.set_search_paths() {
   # there is a version incompatibility issue with other installed plugins, this
   # allows a plugin's preferred version to take precedence.
   @go.search_plugins '_@go.set_search_paths_add_plugin_paths'
-
-  # Ensure a plugin's _GO_SCRIPTS_DIR isn't duplicated in _GO_SEARCH_PATHS.
-  for plugin_path in "${_GO_PLUGINS_PATHS[@]}"; do
-    if [[ "$plugin_path" != "$_GO_SCRIPTS_DIR" ]]; then
-      _GO_SEARCH_PATHS+=("$plugin_path")
-    fi
-  done
+  _GO_SEARCH_PATHS+=("${_GO_PLUGINS_PATHS[@]}")
 }
 
 if [[ "${#_GO_SEARCH_PATHS[@]}" -eq 0 ]]; then

tests/core/plugin-scope-variable-values.bats

@@ -104,7 +104,6 @@ assert_scope_values_equal() {
     '_GO_SCRIPTS_DIR:' \
     "$TEST_GO_PLUGINS_DIR/first/bin" \
     '_GO_PLUGINS_PATHS:' \
-    "$TEST_GO_PLUGINS_DIR/first/bin" \
     "$TEST_GO_PLUGINS_DIR/second/bin" \
     '_GO_SEARCH_PATHS:' \
     "$_GO_CORE_DIR/libexec" \
@@ -131,7 +130,6 @@ assert_scope_values_equal() {
     '_GO_SCRIPTS_DIR:' \
     "$TEST_GO_PLUGINS_DIR/second/bin/plugins/third/bin" \
     '_GO_PLUGINS_PATHS:' \
-    "$TEST_GO_PLUGINS_DIR/second/bin/plugins/third/bin" \
     "$TEST_GO_PLUGINS_DIR/first/bin" \
     "$TEST_GO_PLUGINS_DIR/second/bin" \
     '_GO_SEARCH_PATHS:' \
@@ -151,7 +149,6 @@ assert_scope_values_equal() {
     '_GO_PLUGINS_PATHS:' \
     "$TEST_GO_PLUGINS_DIR/second/bin/plugins/third/bin" \
     "$TEST_GO_PLUGINS_DIR/first/bin" \
-    "$TEST_GO_PLUGINS_DIR/second/bin" \
     '_GO_SEARCH_PATHS:' \
     "$_GO_CORE_DIR/libexec" \
     "$TEST_GO_PLUGINS_DIR/second/bin" \
@@ -173,7 +170,6 @@ assert_scope_values_equal() {
     '_GO_SCRIPTS_DIR:' \
     "$TEST_GO_PLUGINS_DIR/first/bin" \
     '_GO_PLUGINS_PATHS:' \
-    "$TEST_GO_PLUGINS_DIR/first/bin" \
     "$TEST_GO_PLUGINS_DIR/second/bin" \
     '_GO_SEARCH_PATHS:' \
     "$_GO_CORE_DIR/libexec" \
@@ -189,7 +185,6 @@ assert_scope_values_equal() {
     '_GO_PLUGINS_PATHS:' \
     "$TEST_GO_PLUGINS_DIR/second/bin/plugins/third/bin" \
     "$TEST_GO_PLUGINS_DIR/first/bin" \
-    "$TEST_GO_PLUGINS_DIR/second/bin" \
     '_GO_SEARCH_PATHS:' \
     "$_GO_CORE_DIR/libexec" \
     "$TEST_GO_PLUGINS_DIR/second/bin" \