From d8a13a37f0715d3063f947f60533ae29c260104c Mon Sep 17 00:00:00 2001
From: S-H-GAMELINKS <gamelinks007@gmail.com>
Date: Tue, 30 Dec 2025 13:19:46 +0900
Subject: [PATCH] Introduce Kanayago LSP that provides real-time Ruby syntax
 checking

Kanayago is a Ruby Language Server Protocol (LSP) implementation that provides:
- Real-time Ruby syntax checking based on parse.y AST
- AST-based Ruby code analysis
- A lightweight LSP implementation written entirely in Ruby

Users need to have the `kanayago` command available in their PATH:

```bash
gem install kanayago
```
---
 extension.toml                   |  4 +++
 src/language_servers/kanayago.rs | 43 ++++++++++++++++++++++++++++++++
 src/language_servers/mod.rs      |  2 ++
 src/ruby.rs                      |  7 +++++-
 4 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 src/language_servers/kanayago.rs

diff --git a/extension.toml b/extension.toml
index 9c21154..cb94210 100644
--- a/extension.toml
+++ b/extension.toml
@@ -38,6 +38,10 @@ languages = ["Ruby"]
 name = "Herb"
 languages = ["HTML+ERB"]
 
+[language_servers.kanayago]
+name = "Kanayago"
+languages = ["Ruby"]
+
 [grammars.ruby]
 repository = "https://github.com/tree-sitter/tree-sitter-ruby"
 commit = "71bd32fb7607035768799732addba884a37a6210"
diff --git a/src/language_servers/kanayago.rs b/src/language_servers/kanayago.rs
new file mode 100644
index 0000000..a4a2071
--- /dev/null
+++ b/src/language_servers/kanayago.rs
@@ -0,0 +1,43 @@
+use super::{language_server::WorktreeLike, LanguageServer};
+
+pub struct Kanayago {}
+
+
+impl LanguageServer for Kanayago {
+    const SERVER_ID: &str = "kanayago";
+    const EXECUTABLE_NAME: &str = "kanayago";
+    const GEM_NAME: &str = "kanayago";
+
+    fn get_executable_args<T: WorktreeLike>(&self, _worktree: &T) -> Vec<String> {
+        vec!["--lsp".to_string()]
+    }
+}
+
+impl Kanayago {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::language_servers::{language_server::FakeWorktree, LanguageServer, Kanayago};
+
+    #[test]
+    fn test_server_id() {
+        assert_eq!(Kanayago::SERVER_ID, "kanayago");
+    }
+
+    #[test]
+    fn test_executable_name() {
+        assert_eq!(Kanayago::EXECUTABLE_NAME, "kanayago");
+    }
+
+    #[test]
+    fn test_executable_args() {
+        let kanayago = Kanayago::new();
+        let mock_worktree = FakeWorktree::new("/path/to/project".to_string());
+
+        assert_eq!(kanayago.get_executable_args(&mock_worktree), vec!["--lsp"]);
+    }
+}
diff --git a/src/language_servers/mod.rs b/src/language_servers/mod.rs
index 57d7184..7f13ddd 100644
--- a/src/language_servers/mod.rs
+++ b/src/language_servers/mod.rs
@@ -1,3 +1,4 @@
+mod kanayago;
 mod herb;
 mod language_server;
 mod rubocop;
@@ -6,6 +7,7 @@ mod solargraph;
 mod sorbet;
 mod steep;
 
+pub use kanayago::Kanayago;
 pub use herb::Herb;
 pub use language_server::LanguageServer;
 pub use rubocop::Rubocop;
diff --git a/src/ruby.rs b/src/ruby.rs
index e1b1a70..bc48b69 100644
--- a/src/ruby.rs
+++ b/src/ruby.rs
@@ -8,7 +8,7 @@ use std::{collections::HashMap, path::PathBuf};
 use bundler::Bundler;
 use command_executor::RealCommandExecutor;
 use gemset::Gemset;
-use language_servers::{Herb, LanguageServer, Rubocop, RubyLsp, Solargraph, Sorbet, Steep};
+use language_servers::{Kanayago, Herb, LanguageServer, Rubocop, RubyLsp, Solargraph, Sorbet, Steep};
 use serde::{Deserialize, Serialize};
 use zed_extension_api::{
     self as zed, resolve_tcp_template, DebugAdapterBinary, DebugConfig, DebugRequest,
@@ -24,6 +24,7 @@ struct RubyExtension {
     sorbet: Option<Sorbet>,
     steep: Option<Steep>,
     herb: Option<Herb>,
+    kanayago: Option<Kanayago>,
 }
 
 #[derive(Serialize, Deserialize)]
@@ -73,6 +74,10 @@ impl zed::Extension for RubyExtension {
                 let herb = self.herb.get_or_insert_with(Herb::new);
                 herb.language_server_command(language_server_id, worktree)
             }
+            Kanayago::SERVER_ID => {
+                let kanayago = self.kanayago.get_or_insert_with(Kanayago::new);
+                kanayago.language_server_command(language_server_id, worktree)
+            }
             language_server_id => Err(format!("unknown language server: {language_server_id}")),
         }
     }