fix(_comp_{load,realcommand}): handle option-like command name

bash_completion

@@ -2201,7 +2201,7 @@ _comp_realcommand()
 {
     REPLY=""
     local file
-    file=$(type -P "$1") || return $?
+    file=$(type -P -- "$1") || return $?
     if type -p realpath >/dev/null; then
         REPLY=$(realpath "$file")
     elif type -p greadlink >/dev/null; then
@@ -3153,7 +3153,7 @@ _comp_load()
 
     # Resolve absolute path to $cmd
     local REPLY pathcmd origcmd=$cmd
-    if pathcmd=$(type -P "$cmd"); then
+    if pathcmd=$(type -P -- "$cmd"); then
         _comp_abspath "$pathcmd"
         cmd=$REPLY
     fi

test/t/unit/test_unit_load.py

@@ -128,3 +128,6 @@ def test_cmd_intree_precedence(self, bash, fixture_dir):
             # The in-tree `sh` completion should be loaded here,
             # and cause no output, unlike our `$PWD/prefix1/bin/sh` canary.
             assert_bash_exec(bash, "_comp_load sh", want_output=False)
+
+    def test_option_like_cmd_name(self, bash):
+        assert_bash_exec(bash, "! _comp_load -- --non-existent")

test/t/unit/test_unit_realcommand.py

@@ -88,3 +88,11 @@ def test_absolute_nonexistent(self, bash, functions):
             want_output=False,
         )
         assert output.strip() == ""
+
+    def test_option_like_cmd_name(self, bash, functions):
+        output = assert_bash_exec(
+            bash,
+            "! __tester --non-existent",
+            want_output=False,
+        )
+        assert output.strip() == ""