Add rbenv's own `rbenv.d` directory to hook paths

This allows rbenv source code to ship with built-in hooks.

libexec/rbenv

@@ -71,15 +71,20 @@ shopt -s nullglob
 
 bin_path="$(abs_dirname "$0")"
 for plugin_bin in "${RBENV_ROOT}/plugins/"*/bin; do
-  bin_path="${bin_path}:${plugin_bin}"
+  PATH="${plugin_bin}:${PATH}"
 done
 export PATH="${bin_path}:${PATH}"
 
-hook_path="${RBENV_HOOK_PATH}:${RBENV_ROOT}/rbenv.d:/usr/local/etc/rbenv.d:/etc/rbenv.d:/usr/lib/rbenv/hooks"
+RBENV_HOOK_PATH="${RBENV_HOOK_PATH}:${RBENV_ROOT}/rbenv.d"
+if [ "${bin_path%/*}" != "$RBENV_ROOT" ]; then
+  # Add rbenv's own `rbenv.d` unless rbenv was cloned to RBENV_ROOT
+  RBENV_HOOK_PATH="${RBENV_HOOK_PATH}:${bin_path%/*}/rbenv.d"
+fi
+RBENV_HOOK_PATH="${RBENV_HOOK_PATH}:/usr/local/etc/rbenv.d:/etc/rbenv.d:/usr/lib/rbenv/hooks"
 for plugin_hook in "${RBENV_ROOT}/plugins/"*/etc/rbenv.d; do
-  hook_path="${hook_path}:${plugin_hook}"
+  RBENV_HOOK_PATH="${RBENV_HOOK_PATH}:${plugin_hook}"
 done
-export RBENV_HOOK_PATH="$hook_path"
+export RBENV_HOOK_PATH
 
 shopt -u nullglob
 

test/rbenv.bats

@@ -68,3 +68,8 @@ load test_helper
   assert_line 1 "/other/hooks"
   assert_line 2 "${RBENV_ROOT}/rbenv.d"
 }
+
+@test "RBENV_HOOK_PATH includes rbenv built-in plugins" {
+  run rbenv echo "RBENV_HOOK_PATH"
+  assert_success ":${RBENV_ROOT}/rbenv.d:${BATS_TEST_DIRNAME%/*}/rbenv.d:/usr/local/etc/rbenv.d:/etc/rbenv.d:/usr/lib/rbenv/hooks"
+}