fix(copilot): stop mutating config on read

src/web-server/routes/copilot-routes.ts

@@ -18,9 +18,12 @@ import {
   getCopilotApiInfo,
   getInstalledVersion as getCopilotInstalledVersion,
 } from '../../copilot';
-import { normalizeCopilotConfig } from '../../copilot/copilot-model-normalizer';
+import {
+  normalizeCopilotConfigWithWarnings,
+  type CopilotNormalizationWarning,
+} from '../../copilot/copilot-model-normalizer';
 import { DEFAULT_COPILOT_CONFIG, type CopilotConfig } from '../../config/unified-config-types';
-import { loadOrCreateUnifiedConfig, saveUnifiedConfig } from '../../config/unified-config-loader';
+import { loadOrCreateUnifiedConfig, mutateUnifiedConfig } from '../../config/unified-config-loader';
 import copilotSettingsRoutes from './copilot-settings-routes';
 
 const router = Router();
@@ -40,22 +43,12 @@ function parseOptionalModel(value: unknown): string | undefined {
   return trimmed.length > 0 ? trimmed : undefined;
 }
 
-function persistNormalizedCopilotConfig(
-  config: ReturnType<typeof loadOrCreateUnifiedConfig>,
-  copilotConfig: CopilotConfig
-): void {
-  const current = JSON.stringify(config.copilot ?? DEFAULT_COPILOT_CONFIG);
-  const next = JSON.stringify(copilotConfig);
-  if (current === next) return;
-  config.copilot = copilotConfig;
-  saveUnifiedConfig(config);
-}
-
-function loadNormalizedCopilotConfig(): CopilotConfig {
+function loadEffectiveCopilotConfig(): {
+  config: CopilotConfig;
+  warnings: CopilotNormalizationWarning[];
+} {
   const config = loadOrCreateUnifiedConfig();
-  const copilotConfig = normalizeCopilotConfig(config.copilot ?? DEFAULT_COPILOT_CONFIG);
-  persistNormalizedCopilotConfig(config, copilotConfig);
-  return copilotConfig;
+  return normalizeCopilotConfigWithWarnings(config.copilot ?? DEFAULT_COPILOT_CONFIG);
 }
 
 /**
@@ -63,7 +56,7 @@ function loadNormalizedCopilotConfig(): CopilotConfig {
  */
 router.get('/status', async (_req: Request, res: Response): Promise<void> => {
   try {
-    const copilotConfig = loadNormalizedCopilotConfig();
+    const { config: copilotConfig, warnings } = loadEffectiveCopilotConfig();
     const status = await getCopilotStatus(copilotConfig);
     const installed = isCopilotApiInstalled();
     const version = getCopilotInstalledVersion();
@@ -80,6 +73,7 @@ router.get('/status', async (_req: Request, res: Response): Promise<void> => {
       auto_start: copilotConfig.auto_start,
       rate_limit: copilotConfig.rate_limit,
       wait_on_limit: copilotConfig.wait_on_limit,
+      warnings,
     });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
@@ -91,7 +85,8 @@ router.get('/status', async (_req: Request, res: Response): Promise<void> => {
  */
 router.get('/config', (_req: Request, res: Response): void => {
   try {
-    res.json(loadNormalizedCopilotConfig());
+    const { config: copilotConfig, warnings } = loadEffectiveCopilotConfig();
+    res.json({ ...copilotConfig, warnings });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }
@@ -213,47 +208,51 @@ router.put('/config', (req: Request, res: Response): void => {
       return;
     }
 
-    const config = loadOrCreateUnifiedConfig();
+    let nextCopilotConfig: CopilotConfig = { ...DEFAULT_COPILOT_CONFIG };
+    let warnings: CopilotNormalizationWarning[] = [];
 
-    // Merge updates with existing config
-    const nextCopilotConfig = normalizeCopilotConfig({
-      enabled:
-        (payload.enabled as boolean) ?? config.copilot?.enabled ?? DEFAULT_COPILOT_CONFIG.enabled,
-      auto_start:
-        (payload.auto_start as boolean) ??
-        config.copilot?.auto_start ??
-        DEFAULT_COPILOT_CONFIG.auto_start,
-      port: (payload.port as number) ?? config.copilot?.port ?? DEFAULT_COPILOT_CONFIG.port,
-      account_type:
-        (payload.account_type as 'individual' | 'business' | 'enterprise') ??
-        config.copilot?.account_type ??
-        DEFAULT_COPILOT_CONFIG.account_type,
-      rate_limit:
-        payload.rate_limit !== undefined
-          ? (payload.rate_limit as number | null)
-          : (config.copilot?.rate_limit ?? DEFAULT_COPILOT_CONFIG.rate_limit),
-      wait_on_limit:
-        (payload.wait_on_limit as boolean) ??
-        config.copilot?.wait_on_limit ??
-        DEFAULT_COPILOT_CONFIG.wait_on_limit,
-      model: normalizedModel ?? config.copilot?.model ?? DEFAULT_COPILOT_CONFIG.model,
-      opus_model:
-        'opus_model' in payload
-          ? parseOptionalModel(payload.opus_model)
-          : config.copilot?.opus_model,
-      sonnet_model:
-        'sonnet_model' in payload
-          ? parseOptionalModel(payload.sonnet_model)
-          : config.copilot?.sonnet_model,
-      haiku_model:
-        'haiku_model' in payload
-          ? parseOptionalModel(payload.haiku_model)
-          : config.copilot?.haiku_model,
+    mutateUnifiedConfig((config) => {
+      const currentConfig = config.copilot ?? DEFAULT_COPILOT_CONFIG;
+      const result = normalizeCopilotConfigWithWarnings({
+        enabled:
+          (payload.enabled as boolean) ?? currentConfig.enabled ?? DEFAULT_COPILOT_CONFIG.enabled,
+        auto_start:
+          (payload.auto_start as boolean) ??
+          currentConfig.auto_start ??
+          DEFAULT_COPILOT_CONFIG.auto_start,
+        port: (payload.port as number) ?? currentConfig.port ?? DEFAULT_COPILOT_CONFIG.port,
+        account_type:
+          (payload.account_type as 'individual' | 'business' | 'enterprise') ??
+          currentConfig.account_type ??
+          DEFAULT_COPILOT_CONFIG.account_type,
+        rate_limit:
+          payload.rate_limit !== undefined
+            ? (payload.rate_limit as number | null)
+            : (currentConfig.rate_limit ?? DEFAULT_COPILOT_CONFIG.rate_limit),
+        wait_on_limit:
+          (payload.wait_on_limit as boolean) ??
+          currentConfig.wait_on_limit ??
+          DEFAULT_COPILOT_CONFIG.wait_on_limit,
+        model: normalizedModel ?? currentConfig.model ?? DEFAULT_COPILOT_CONFIG.model,
+        opus_model:
+          'opus_model' in payload
+            ? parseOptionalModel(payload.opus_model)
+            : currentConfig.opus_model,
+        sonnet_model:
+          'sonnet_model' in payload
+            ? parseOptionalModel(payload.sonnet_model)
+            : currentConfig.sonnet_model,
+        haiku_model:
+          'haiku_model' in payload
+            ? parseOptionalModel(payload.haiku_model)
+            : currentConfig.haiku_model,
+      });
+      config.copilot = result.config;
+      nextCopilotConfig = result.config;
+      warnings = result.warnings;
     });
 
-    config.copilot = nextCopilotConfig;
-    saveUnifiedConfig(config);
-    res.json({ success: true, copilot: nextCopilotConfig });
+    res.json({ success: true, copilot: nextCopilotConfig, warnings });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }
@@ -288,7 +287,7 @@ router.get('/auth/status', async (_req: Request, res: Response): Promise<void> =
  */
 router.get('/models', async (_req: Request, res: Response): Promise<void> => {
   try {
-    const copilotConfig = loadNormalizedCopilotConfig();
+    const { config: copilotConfig, warnings } = loadEffectiveCopilotConfig();
     const port = copilotConfig.port;
     const currentModel = copilotConfig.model;
     const models = await getCopilotModels(port);
@@ -298,7 +297,7 @@ router.get('/models', async (_req: Request, res: Response): Promise<void> => {
       isCurrent: m.id === currentModel,
     }));
 
-    res.json({ models: modelsWithCurrent, current: currentModel });
+    res.json({ models: modelsWithCurrent, current: currentModel, warnings });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }
@@ -309,8 +308,8 @@ router.get('/models', async (_req: Request, res: Response): Promise<void> => {
  */
 router.get('/usage', async (_req: Request, res: Response): Promise<void> => {
   try {
-    const config = loadOrCreateUnifiedConfig();
-    const port = config.copilot?.port ?? DEFAULT_COPILOT_CONFIG.port;
+    const { config: copilotConfig, warnings } = loadEffectiveCopilotConfig();
+    const port = copilotConfig.port;
     const daemonRunning = await isDaemonRunning(port);
 
     if (!daemonRunning) {
@@ -330,7 +329,7 @@ router.get('/usage', async (_req: Request, res: Response): Promise<void> => {
       return;
     }
 
-    res.json(usage);
+    res.json({ ...usage, warnings });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }
@@ -341,10 +340,9 @@ router.get('/usage', async (_req: Request, res: Response): Promise<void> => {
  */
 router.post('/daemon/start', async (_req: Request, res: Response): Promise<void> => {
   try {
-    const config = loadOrCreateUnifiedConfig();
-    const copilotConfig = config.copilot ?? DEFAULT_COPILOT_CONFIG;
+    const { config: copilotConfig, warnings } = loadEffectiveCopilotConfig();
     const result = await startCopilotDaemon(copilotConfig);
-    res.json(result);
+    res.json({ ...result, warnings });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }

src/web-server/routes/copilot-settings-routes.ts

@@ -6,12 +6,12 @@ import { Router, Request, Response } from 'express';
 import * as fs from 'fs';
 import * as path from 'path';
 import {
-  normalizeCopilotConfig,
-  normalizeCopilotSettings,
+  normalizeCopilotConfigWithWarnings,
+  normalizeCopilotSettingsWithWarnings,
 } from '../../copilot/copilot-model-normalizer';
-import { getCcsDir } from '../../utils/config-manager';
 import { DEFAULT_COPILOT_CONFIG, type CopilotConfig } from '../../config/unified-config-types';
-import { loadOrCreateUnifiedConfig, saveUnifiedConfig } from '../../config/unified-config-loader';
+import { loadOrCreateUnifiedConfig, mutateUnifiedConfig } from '../../config/unified-config-loader';
+import { getCcsDir } from '../../utils/config-manager';
 
 const router = Router();
 
@@ -26,20 +26,40 @@ function writeSettingsFile(
 ): void {
   const nextContent = serializeSettings(settings);
   if (previousContent === nextContent) return;
-  const tempPath = `${settingsPath}.tmp`;
+  const tempPath = `${settingsPath}.${process.pid}.${Date.now()}.${Math.random().toString(36).slice(2)}.tmp`;
   fs.writeFileSync(tempPath, nextContent);
   fs.renameSync(tempPath, settingsPath);
 }
 
-function persistNormalizedCopilotConfig(
-  config: ReturnType<typeof loadOrCreateUnifiedConfig>,
-  copilotConfig: CopilotConfig
+function restoreSettingsFile(
+  settingsPath: string,
+  previousContent: string | undefined,
+  existedBefore: boolean
 ): void {
-  const current = JSON.stringify(config.copilot ?? DEFAULT_COPILOT_CONFIG);
-  const next = JSON.stringify(copilotConfig);
-  if (current === next) return;
-  config.copilot = copilotConfig;
-  saveUnifiedConfig(config);
+  if (!existedBefore) {
+    if (fs.existsSync(settingsPath)) {
+      fs.unlinkSync(settingsPath);
+    }
+    return;
+  }
+
+  const tempPath = `${settingsPath}.${process.pid}.${Date.now()}.${Math.random().toString(36).slice(2)}.restore.tmp`;
+  fs.writeFileSync(tempPath, previousContent ?? '');
+  fs.renameSync(tempPath, settingsPath);
+}
+
+function buildDefaultSettings(copilotConfig: CopilotConfig) {
+  return {
+    env: {
+      ANTHROPIC_BASE_URL: `http://127.0.0.1:${copilotConfig.port}`,
+      ANTHROPIC_AUTH_TOKEN: 'copilot-managed',
+      ANTHROPIC_MODEL: copilotConfig.model,
+      ANTHROPIC_DEFAULT_OPUS_MODEL: copilotConfig.opus_model || copilotConfig.model,
+      ANTHROPIC_DEFAULT_SONNET_MODEL: copilotConfig.sonnet_model || copilotConfig.model,
+      ANTHROPIC_DEFAULT_HAIKU_MODEL: copilotConfig.haiku_model || copilotConfig.model,
+      ANTHROPIC_SMALL_FAST_MODEL: copilotConfig.haiku_model || copilotConfig.model,
+    },
+  };
 }
 
 /**
@@ -50,74 +70,39 @@ router.get('/raw', (_req: Request, res: Response): void => {
   try {
     const settingsPath = path.join(getCcsDir(), 'copilot.settings.json');
     const config = loadOrCreateUnifiedConfig();
-    const copilotConfig = normalizeCopilotConfig(config.copilot ?? DEFAULT_COPILOT_CONFIG);
-    persistNormalizedCopilotConfig(config, copilotConfig);
+    const configResult = normalizeCopilotConfigWithWarnings(
+      config.copilot ?? DEFAULT_COPILOT_CONFIG
+    );
 
-    // Default model for all tiers
-    const defaultModel = copilotConfig.model;
-
-    // If file doesn't exist, return default structure with all model mappings
     if (!fs.existsSync(settingsPath)) {
-      // Create settings structure matching CLIProxy pattern
-      // Use 127.0.0.1 instead of localhost for more reliable local connections
-      const defaultSettings = normalizeCopilotSettings(
-        {
-          env: {
-            ANTHROPIC_BASE_URL: `http://127.0.0.1:${copilotConfig.port}`,
-            ANTHROPIC_AUTH_TOKEN: 'copilot-managed',
-            ANTHROPIC_MODEL: defaultModel,
-            ANTHROPIC_DEFAULT_OPUS_MODEL: copilotConfig.opus_model || defaultModel,
-            ANTHROPIC_DEFAULT_SONNET_MODEL: copilotConfig.sonnet_model || defaultModel,
-            ANTHROPIC_DEFAULT_HAIKU_MODEL: copilotConfig.haiku_model || defaultModel,
-          },
-        },
-        copilotConfig
+      const defaultSettings = normalizeCopilotSettingsWithWarnings(
+        buildDefaultSettings(configResult.config),
+        configResult.config
       );
 
       res.json({
-        settings: defaultSettings,
+        settings: defaultSettings.settings,
+        effectiveSettings: defaultSettings.settings,
         mtime: Date.now(),
         path: `~/.ccs/copilot.settings.json`,
         exists: false,
+        warnings: defaultSettings.warnings,
       });
       return;
     }
 
     const content = fs.readFileSync(settingsPath, 'utf-8');
-    const settings = normalizeCopilotSettings(
-      JSON.parse(content) as Record<string, unknown>,
-      copilotConfig
-    );
-    writeSettingsFile(settingsPath, settings, content);
-
-    const env =
-      settings.env && typeof settings.env === 'object' && !Array.isArray(settings.env)
-        ? settings.env
-        : {};
-    persistNormalizedCopilotConfig(config, {
-      ...copilotConfig,
-      model: typeof env.ANTHROPIC_MODEL === 'string' ? env.ANTHROPIC_MODEL : copilotConfig.model,
-      opus_model:
-        typeof env.ANTHROPIC_DEFAULT_OPUS_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_OPUS_MODEL
-          : undefined,
-      sonnet_model:
-        typeof env.ANTHROPIC_DEFAULT_SONNET_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_SONNET_MODEL
-          : undefined,
-      haiku_model:
-        typeof env.ANTHROPIC_DEFAULT_HAIKU_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_HAIKU_MODEL
-          : undefined,
-    });
-
+    const rawSettings = JSON.parse(content) as Record<string, unknown>;
+    const settingsResult = normalizeCopilotSettingsWithWarnings(rawSettings, configResult.config);
     const stat = fs.statSync(settingsPath);
 
     res.json({
-      settings,
+      settings: rawSettings,
+      effectiveSettings: settingsResult.settings,
       mtime: stat.mtimeMs,
       path: `~/.ccs/copilot.settings.json`,
       exists: true,
+      warnings: settingsResult.warnings,
     });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
@@ -132,8 +117,16 @@ router.put('/raw', (req: Request, res: Response): void => {
   try {
     const { settings, expectedMtime } = req.body;
     const settingsPath = path.join(getCcsDir(), 'copilot.settings.json');
-    const config = loadOrCreateUnifiedConfig();
-    const copilotConfig = normalizeCopilotConfig(config.copilot ?? DEFAULT_COPILOT_CONFIG);
+
+    if (!settings || typeof settings !== 'object' || Array.isArray(settings)) {
+      res.status(400).json({ error: 'settings must be a JSON object' });
+      return;
+    }
+
+    const currentConfig = loadOrCreateUnifiedConfig();
+    const configResult = normalizeCopilotConfigWithWarnings(
+      currentConfig.copilot ?? DEFAULT_COPILOT_CONFIG
+    );
 
     // Check for conflict if file exists and expectedMtime provided
     if (fs.existsSync(settingsPath) && expectedMtime) {
@@ -144,43 +137,40 @@ router.put('/raw', (req: Request, res: Response): void => {
       }
     }
 
-    const normalizedSettings = normalizeCopilotSettings(
+    const settingsResult = normalizeCopilotSettingsWithWarnings(
       settings as Record<string, unknown>,
-      copilotConfig
+      configResult.config
+    );
+    const existedBefore = fs.existsSync(settingsPath);
+    const previousContent = existedBefore ? fs.readFileSync(settingsPath, 'utf-8') : undefined;
+    writeSettingsFile(
+      settingsPath,
+      settingsResult.settings as Record<string, unknown>,
+      previousContent
     );
-    writeSettingsFile(settingsPath, normalizedSettings);
 
-    // Also sync model mappings back to unified config
-    const env =
-      normalizedSettings.env &&
-      typeof normalizedSettings.env === 'object' &&
-      !Array.isArray(normalizedSettings.env)
-        ? normalizedSettings.env
-        : {};
-
-    config.copilot = normalizeCopilotConfig({
-      ...(config.copilot ?? DEFAULT_COPILOT_CONFIG),
-      model:
-        typeof env.ANTHROPIC_MODEL === 'string'
-          ? env.ANTHROPIC_MODEL
-          : config.copilot?.model || DEFAULT_COPILOT_CONFIG.model,
-      opus_model:
-        typeof env.ANTHROPIC_DEFAULT_OPUS_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_OPUS_MODEL
-          : undefined,
-      sonnet_model:
-        typeof env.ANTHROPIC_DEFAULT_SONNET_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_SONNET_MODEL
-          : undefined,
-      haiku_model:
-        typeof env.ANTHROPIC_DEFAULT_HAIKU_MODEL === 'string'
-          ? env.ANTHROPIC_DEFAULT_HAIKU_MODEL
-          : undefined,
-    });
-    saveUnifiedConfig(config);
+    try {
+      mutateUnifiedConfig((config) => {
+        config.copilot = settingsResult.effectiveConfig;
+      });
+    } catch (error) {
+      try {
+        restoreSettingsFile(settingsPath, previousContent, existedBefore);
+      } catch (rollbackError) {
+        throw new Error(
+          `Failed to sync unified config after writing Copilot settings: ${(error as Error).message}. Rollback also failed: ${(rollbackError as Error).message}`
+        );
+      }
+      throw error;
+    }
 
     const stat = fs.statSync(settingsPath);
-    res.json({ success: true, mtime: stat.mtimeMs });
+    res.json({
+      success: true,
+      mtime: stat.mtimeMs,
+      settings: settingsResult.settings,
+      warnings: settingsResult.warnings,
+    });
   } catch (error) {
     res.status(500).json({ error: (error as Error).message });
   }