修复配置覆盖层写入失败后的部分更新

提前序列化配置变更并在多文件写入失败时逆序回滚
保留单文件保存路径且不增加外部诊断或保存后回读
补充覆盖层写入失败回归测试及配置保存文档

apps/ai-game-creator-shell/src-tauri/src/commands.rs

@@ -2040,7 +2040,7 @@ fn persist_game_creator_app_config(
     let config = normalize_game_creator_app_config(config)?;
     let path = writable_game_creator_config_path()?;
     let content = serialize_game_creator_app_config_for_renderer_write(&config)?;
-    write_game_creator_config_atomically(&path, &format!("{content}\n"))?;
+    let mut writes = vec![(path, format!("{content}\n"))];
     let saved: serde_json::Value = serde_json::from_str(&content)
         .map_err(|error| format!("解析已序列化客户端配置失败：{error}"))?;
     for (overlay_path, mut overlay) in overlays {
@@ -2062,9 +2062,10 @@ fn persist_game_creator_app_config(
         if overlay != previous {
             let content = serde_json::to_string_pretty(&overlay)
                 .map_err(|error| format!("序列化客户端覆盖配置失败：{error}"))?;
-            write_game_creator_config_atomically(&overlay_path, &format!("{content}\n"))?;
+            writes.push((overlay_path, format!("{content}\n")));
         }
     }
+    crate::config::write_game_creator_config_batch(&writes)?;
     // `config` is already normalized and is exactly what was persisted.
     // Avoid reloading it here: a reload repeats the Windows private-path and
     // ACL checks and made saving the settings panel appear to hang.

apps/ai-game-creator-shell/src-tauri/src/config.rs

@@ -3678,6 +3678,45 @@ fn game_creator_config_backup_path(path: &Path) -> PathBuf {
     ))
 }
 
+pub(crate) fn write_game_creator_config_batch(writes: &[(PathBuf, String)]) -> Result<(), String> {
+    if writes.len() == 1 {
+        return write_game_creator_config_atomically(&writes[0].0, &writes[0].1);
+    }
+    let originals = writes
+        .iter()
+        .map(|(path, _)| read_game_creator_config_file(path))
+        .collect::<Result<Vec<_>, _>>()?;
+    for (index, (path, content)) in writes.iter().enumerate() {
+        if let Err(mut error) = write_game_creator_config_atomically(path, content) {
+            // 写入可能在替换后的权限检查失败，因此失败目标也需要核对并恢复。
+            for rollback_index in (0..=index).rev() {
+                let path = &writes[rollback_index].0;
+                let original = &originals[rollback_index];
+                if read_game_creator_config_file(path).ok().as_ref() == Some(original) {
+                    continue;
+                }
+                let restored = match original {
+                    Some(content) => write_game_creator_config_atomically(path, content),
+                    None => fs::remove_file(path)
+                        .or_else(|error| {
+                            if error.kind() == std::io::ErrorKind::NotFound {
+                                Ok(())
+                            } else {
+                                Err(error)
+                            }
+                        })
+                        .map_err(|error| error.to_string()),
+                };
+                if let Err(restore_error) = restored {
+                    error.push_str(&format!("；恢复配置失败：{}: {restore_error}", path.display()));
+                }
+            }
+            return Err(error);
+        }
+    }
+    Ok(())
+}
+
 pub(crate) fn write_game_creator_config_atomically(
     path: &Path,
     content: &str,

apps/ai-game-creator-shell/src-tauri/src/tests/configuration.rs

@@ -807,6 +807,36 @@ fn app_config_commands_write_runtime_config_file() {
     fs::remove_dir_all(root).expect("cleanup runtime config dir");
 }
 
+#[test]
+fn app_config_batch_restores_main_when_overlay_write_fails() {
+    for main_exists in [false, true] {
+        let root = unique_project_path();
+        fs::create_dir_all(&root).expect("config dir");
+        let main = root.join(GAME_CREATOR_CONFIG_FILE_NAME);
+        let overlay = root.join(GAME_CREATOR_LOCAL_CONFIG_FILE_NAME);
+        let original = "{\"llm\":{\"stream\":false}}\n";
+        if main_exists {
+            fs::write(&main, original).expect("main config");
+        }
+        fs::write(&overlay, original).expect("overlay config");
+        // 普通目录占据备份路径，让覆盖文件在替换前失败。
+        fs::create_dir(root.join(format!(".{}.previous", GAME_CREATOR_LOCAL_CONFIG_FILE_NAME)))
+            .expect("block overlay replacement");
+        crate::config::write_game_creator_config_batch(&[
+            (main.clone(), "{\"llm\":{\"stream\":true}}\n".to_string()),
+            (overlay.clone(), "{\"llm\":{\"stream\":true}}\n".to_string()),
+        ])
+        .expect_err("overlay replacement must fail");
+        if main_exists {
+            assert_eq!(fs::read_to_string(&main).expect("restored main"), original);
+        } else {
+            assert!(!main.exists());
+        }
+        assert_eq!(fs::read_to_string(&overlay).expect("unchanged overlay"), original);
+        fs::remove_dir_all(root).expect("cleanup config dir");
+    }
+}
+
 #[test]
 fn app_config_save_updates_conflicting_local_overlay() {
     let root = unique_project_path();