From cd9d8545950f9886785193141bba7df152159f8e Mon Sep 17 00:00:00 2001
From: Hare <kei.hiracchi.0928@gmail.com>
Date: Sun, 30 Aug 2026 21:36:33 +0900
Subject: [PATCH] fix: reject standalone runtime selectors

---
 crates/yoi/src/main.rs | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/crates/yoi/src/main.rs b/crates/yoi/src/main.rs
index 01cd92ca..262b9af7 100644
--- a/crates/yoi/src/main.rs
+++ b/crates/yoi/src/main.rs
@@ -755,6 +755,12 @@ fn parse_console_options<R: CliConnectionResolver + ?Sized>(
     }
 
     if target.kind() == TargetKind::Standalone {
+        if runtime_id.is_some() || worker_id.is_some() {
+            return Err(ParseError(
+                "Standalone does not accept Backend Runtime selectors; use --backend with --runtime-id/--worker-id"
+                    .to_string(),
+            ));
+        }
         if session.is_some() {
             return Err(ParseError(
                 "--local does not accept legacy --session; use --local --resume for Standalone session restore"
@@ -2045,6 +2051,25 @@ backend = "shared"
         }
     }
 
+    #[test]
+    fn parse_standalone_rejects_backend_runtime_selectors() {
+        let runtime_error = parse_args_from(["--local", "--runtime-id", "runtime-a"])
+            .unwrap_err()
+            .to_string();
+        assert!(runtime_error.contains("Standalone does not accept Backend Runtime selectors"));
+
+        let worker_error = parse_args_from([
+            "--local",
+            "--runtime-id",
+            "runtime-a",
+            "--worker-id",
+            "worker-b",
+        ])
+        .unwrap_err()
+        .to_string();
+        assert!(worker_error.contains("Standalone does not accept Backend Runtime selectors"));
+    }
+
     #[test]
     fn parse_backend_runtime_target_requires_runtime_for_worker_identity() {
         let err = parse_args_from(["--backend", "http://127.0.0.1:8787", "--worker-id", "w"])