From 70eca3525a5c87a638a138611fe233936dcd6708 Mon Sep 17 00:00:00 2001
From: H-Chris233 <h-chris233@outlook.com>
Date: Thu, 30 Apr 2026 21:50:09 +0800
Subject: [PATCH] Serialize credentials file updates

Credentials writes use a load-modify-save JSON path, so concurrent Settings debounce saves could read the same stale root and overwrite each other. Guard the CredentialsVault file accessors with one process-wide mutex to keep read-modify-write operations ordered.

Constraint: Issue #61 asks for minimal protection around the existing JSON vault path

Rejected: Atomic compare-and-swap rewrite | broader than needed for current single-process Tauri writes

Confidence: high

Scope-risk: narrow

Tested: cargo check --manifest-path openless-all/app/src-tauri/Cargo.toml

Tested: git diff --check
---
 openless-all/app/src-tauri/src/persistence.rs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/openless-all/app/src-tauri/src/persistence.rs b/openless-all/app/src-tauri/src/persistence.rs
index a9ec2e99..3d772ace 100644
--- a/openless-all/app/src-tauri/src/persistence.rs
+++ b/openless-all/app/src-tauri/src/persistence.rs
@@ -14,6 +14,7 @@
 
 use std::fs;
 use std::path::{Path, PathBuf};
+use std::sync::OnceLock;
 
 use anyhow::{anyhow, Context, Result};
 use chrono::Utc;
@@ -36,6 +37,12 @@ const VOCAB_FILE: &str = "dictionary.json";
 const LEGACY_CREDS_DIR: &str = ".openless";
 const LEGACY_CREDS_FILE: &str = "credentials.json";
 
+static CREDENTIALS_LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+
+fn credentials_lock() -> &'static Mutex<()> {
+    CREDENTIALS_LOCK.get_or_init(|| Mutex::new(()))
+}
+
 // ───────────────────────── path helpers ─────────────────────────
 
 fn data_dir() -> Result<PathBuf> {
@@ -657,10 +664,12 @@ impl CredentialsVault {
     pub const SERVICE_NAME: &'static str = "com.openless.app";
 
     pub fn get(account: CredentialAccount) -> Result<Option<String>> {
+        let _guard = credentials_lock().lock();
         Ok(lookup_account(&load_credentials(), account))
     }
 
     pub fn set(account: CredentialAccount, value: &str) -> Result<()> {
+        let _guard = credentials_lock().lock();
         let mut root = load_credentials();
         let v = if value.is_empty() {
             None
@@ -672,28 +681,33 @@ impl CredentialsVault {
     }
 
     pub fn remove(account: CredentialAccount) -> Result<()> {
+        let _guard = credentials_lock().lock();
         let mut root = load_credentials();
         write_account(&mut root, account, None);
         save_credentials(&root)
     }
 
     pub fn get_active_asr() -> String {
+        let _guard = credentials_lock().lock();
         load_credentials().active.asr
     }
 
     pub fn set_active_asr_provider(id: &str) -> Result<()> {
+        let _guard = credentials_lock().lock();
         let mut root = load_credentials();
         root.active.asr = id.to_string();
         save_credentials(&root)
     }
 
     pub fn set_active_llm_provider(id: &str) -> Result<()> {
+        let _guard = credentials_lock().lock();
         let mut root = load_credentials();
         root.active.llm = id.to_string();
         save_credentials(&root)
     }
 
     pub fn snapshot() -> CredentialsSnapshot {
+        let _guard = credentials_lock().lock();
         let root = load_credentials();
         CredentialsSnapshot {
             volcengine_app_key: lookup_account(&root, CredentialAccount::VolcengineAppKey),