feat: add setting require_config_file

README.md

@@ -72,6 +72,21 @@ Instead, you can configure biome as an external formatter:
 }
 ```
 
+### Enable biome only when biome.json is present
+
+```jsonc
+// settings.json
+{
+  "lsp": {
+    "biome": {
+      "settings": {
+        "require_config_file": true
+      }
+    }
+  }
+}
+```
+
 ### Project based configuration
 
 If you'd like to exclude biome from running in every project,
@@ -107,4 +122,3 @@ The same can be configured on a per-lanugage bassis with the [`languages`](https
   }
 }
 ```
-

src/biome.rs

@@ -1,10 +1,16 @@
 use std::{env, fs, path::Path};
 use zed::settings::LspSettings;
-use zed_extension_api::{self as zed, serde_json, LanguageServerId, Result};
+use zed_extension_api::{
+  self as zed,
+  serde_json::{self, Value},
+  LanguageServerId, Result,
+};
 
 const SERVER_PATH: &str = "node_modules/@biomejs/biome/bin/biome";
 const PACKAGE_NAME: &str = "@biomejs/biome";
 
+const BIOME_CONFIG_PATHS: &[&str] = &["biome.json", "biome.jsonc"];
+
 struct BiomeExtension;
 
 impl BiomeExtension {
@@ -74,6 +80,27 @@ impl BiomeExtension {
 
     Ok(fallback_server_path.to_string())
   }
+
+  // Returns the path if a config file exists
+  pub fn config_path(&self, worktree: &zed::Worktree, settings: &Value) -> Option<String> {
+    let config_path_setting = settings.get("config_path").and_then(|value| value.as_str());
+
+    if let Some(config_path) = config_path_setting {
+      if worktree.read_text_file(config_path).is_ok() {
+        return Some(config_path.to_string());
+      } else {
+        return None;
+      }
+    }
+
+    for config_path in BIOME_CONFIG_PATHS {
+      if worktree.read_text_file(config_path).is_ok() {
+        return Some(config_path.to_string());
+      }
+    }
+
+    None
+  }
 }
 
 impl zed::Extension for BiomeExtension {
@@ -99,11 +126,18 @@ impl zed::Extension for BiomeExtension {
     ];
 
     if let Some(settings) = settings.settings {
-      let config_path = settings.get("config_path").and_then(|value| value.as_str());
+      let config_path = self.config_path(worktree, &settings);
+
+      let require_config_file = settings
+        .get("require_config_file")
+        .and_then(|value| value.as_bool())
+        .unwrap_or(false);
 
-      if let Some(path) = config_path {
+      if let Some(config_path) = config_path {
         args.push("--config-path".to_string());
-        args.push(path.to_string());
+        args.push(config_path.clone());
+      } else if require_config_file {
+        return Err("biome.json is not found but require_config_file is true".to_string());
       }
     }