Support prioritizing discovered TOML settings over editor settings (#457

)

## Summary

Fixes #425 (though only
in the pre-release version, since this is a feature for the new LSP
server)

This is a follow-up to
#456.

A new setting has been introduced, `Prioritize File Configuration`,
which tells the extension to prioritize settings from discovered TOML
files over extension settings. Extension settings will still be used
when a set field in the extension is not set in the file configuration.

## Test Plan

Refer to astral-sh/ruff#11086 for a test plan.

package.json

@@ -315,6 +315,22 @@
           "scope": "resource",
           "type": ["integer", "null"]
         },
+        "ruff.configurationPreference": {
+          "enum": [
+            "editorFirst",
+            "filesystemFirst",
+            "editorOnly"
+          ],
+          "enumDescriptions": [
+            "The default strategy - configuration set in the editor takes priority over configuration set in `.toml` files.",
+            "An alternative strategy - configuration set in `.toml` files takes priority over configuration set in the editor.",
+            "An alternative strategy - configuration set in `.toml` files is ignored entirely."
+          ],
+          "markdownDescription": "The preferred method of resolving configuration in the editor with local configuration froml `.toml` files.",
+          "scope": "resource",
+          "type": "string",
+          "default": "editorFirst"
+        },
         "ruff.enableExperimentalFormatter": {
           "default": false,
           "markdownDescription": "Controls whether Ruff registers as capable of code formatting.",

src/common/settings.ts

@@ -11,6 +11,8 @@ type ImportStrategy = "fromEnvironment" | "useBundled";
 
 type Run = "onType" | "onSave";
 
+type ConfigPreference = "editorFirst" | "filesystemFirst" | "editorOnly";
+
 type CodeAction = {
   disableRuleComment?: {
     enable?: boolean;
@@ -53,6 +55,7 @@ export interface ISettings {
   format: Format;
   exclude?: string[];
   lineLength?: number;
+  configurationPreference?: ConfigPreference;
 }
 
 export function getExtensionSettings(namespace: string): Promise<ISettings[]> {
@@ -151,6 +154,8 @@ export async function getWorkspaceSettings(
     showNotifications: config.get<string>("showNotifications") ?? "off",
     exclude: config.get<string[]>("exclude"),
     lineLength: config.get<number>("lineLength"),
+    configurationPreference:
+      config.get<ConfigPreference>("configurationPreference") ?? "editorFirst",
   };
 }
 
@@ -195,6 +200,11 @@ export async function getGlobalSettings(namespace: string): Promise<ISettings> {
     showNotifications: getGlobalValue<string>(config, "showNotifications", "off"),
     exclude: getOptionalGlobalValue<string[]>(config, "exclude"),
     lineLength: getOptionalGlobalValue<number>(config, "lineLength"),
+    configurationPreference: getGlobalValue<ConfigPreference>(
+      config,
+      "configurationPreference",
+      "editorFirst",
+    ),
   };
 }
 
@@ -223,6 +233,7 @@ export function checkIfConfigurationChanged(
     `${namespace}.format.preview`,
     `${namespace}.exclude`,
     `${namespace}.lineLength`,
+    `${namespace}.configurationPreference`,
     // Deprecated settings (prefer `lint.args`, etc.).
     `${namespace}.args`,
     `${namespace}.run`,