fix(config): enforce strict startup config parsing

src/config/config.test.ts

@@ -3,7 +3,7 @@ import assert from 'node:assert/strict';
 import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
-import { ConfigService } from './service';
+import { ConfigService, ConfigStartupParseError } from './service';
 import { DEFAULT_CONFIG, RUNTIME_OPTION_REGISTRY } from './definitions';
 import { generateConfigTemplate } from './template';
 
@@ -39,6 +39,24 @@ test('loads defaults when config is missing', () => {
   assert.equal(config.immersionTracking.retention.vacuumIntervalDays, 7);
 });
 
+test('throws actionable startup parse error for malformed config at construction time', () => {
+  const dir = makeTempDir();
+  const configPath = path.join(dir, 'config.jsonc');
+  fs.writeFileSync(configPath, '{"websocket":', 'utf-8');
+
+  assert.throws(
+    () => new ConfigService(dir),
+    (error: unknown) => {
+      assert.ok(error instanceof ConfigStartupParseError);
+      assert.equal(error.path, configPath);
+      assert.ok(error.parseError.length > 0);
+      assert.ok(error.message.includes(configPath));
+      assert.ok(error.message.includes(error.parseError));
+      return true;
+    },
+  );
+});
+
 test('parses subtitleStyle.preserveLineBreaks and warns on invalid values', () => {
   const validDir = makeTempDir();
   fs.writeFileSync(

src/config/service.ts

@@ -18,12 +18,26 @@ export type ReloadConfigStrictResult =
       path: string;
     };
 
+export class ConfigStartupParseError extends Error {
+  readonly path: string;
+  readonly parseError: string;
+
+  constructor(configPath: string, parseError: string) {
+    super(
+      `Failed to parse startup config at ${configPath}: ${parseError}. Fix the config file and restart SubMiner.`,
+    );
+    this.name = 'ConfigStartupParseError';
+    this.path = configPath;
+    this.parseError = parseError;
+  }
+}
+
 export class ConfigService {
   private readonly configPaths: ConfigPaths;
   private rawConfig: RawConfig = {};
   private resolvedConfig: ResolvedConfig = deepCloneConfig(DEFAULT_CONFIG);
   private warnings: ConfigValidationWarning[] = [];
-  private configPathInUse: string;
+  private configPathInUse!: string;
 
   constructor(configDir: string) {
     this.configPaths = {
@@ -31,8 +45,11 @@ export class ConfigService {
       configFileJsonc: path.join(configDir, 'config.jsonc'),
       configFileJson: path.join(configDir, 'config.json'),
     };
-    this.configPathInUse = this.configPaths.configFileJsonc;
-    this.reloadConfig();
+    const loadResult = loadRawConfigStrict(this.configPaths);
+    if (!loadResult.ok) {
+      throw new ConfigStartupParseError(loadResult.path, loadResult.error);
+    }
+    this.applyResolvedConfig(loadResult.config, loadResult.path);
   }
 
   getConfigPath(): string {

src/main/config-validation.test.ts

@@ -1,6 +1,7 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import {
+  buildConfigParseErrorDetails,
   buildConfigWarningNotificationBody,
   buildConfigWarningSummary,
   failStartupFromConfig,
@@ -52,6 +53,15 @@ test('buildConfigWarningNotificationBody includes concise warning details', () =
   );
 });
 
+test('buildConfigParseErrorDetails includes path error and restart guidance', () => {
+  const details = buildConfigParseErrorDetails('/tmp/config.jsonc', 'unexpected token at line 1');
+
+  assert.match(details, /Failed to parse config file at:/);
+  assert.match(details, /\/tmp\/config\.jsonc/);
+  assert.match(details, /Error: unexpected token at line 1/);
+  assert.match(details, /Fix the config file and restart SubMiner\./);
+});
+
 test('failStartupFromConfig invokes handlers and throws', () => {
   const calls: string[] = [];
   const previousExitCode = process.exitCode;

src/main/config-validation.ts

@@ -61,6 +61,17 @@ export function buildConfigWarningNotificationBody(
   ].join('\n');
 }
 
+export function buildConfigParseErrorDetails(configPath: string, parseError: string): string {
+  return [
+    'Failed to parse config file at:',
+    configPath,
+    '',
+    `Error: ${parseError}`,
+    '',
+    'Fix the config file and restart SubMiner.',
+  ].join('\n');
+}
+
 export function failStartupFromConfig(
   title: string,
   details: string,

src/main/runtime/startup-config.test.ts

@@ -1,9 +1,6 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
-import {
-  createCriticalConfigErrorHandler,
-  createReloadConfigHandler,
-} from './startup-config';
+import { createCriticalConfigErrorHandler, createReloadConfigHandler } from './startup-config';
 
 test('createReloadConfigHandler runs success flow with warnings', async () => {
   const calls: string[] = [];
@@ -42,9 +39,7 @@ test('createReloadConfigHandler runs success flow with warnings', async () => {
   assert.ok(calls.some((entry) => entry.startsWith('info:Using config file: /tmp/config.jsonc')));
   assert.ok(calls.some((entry) => entry.startsWith('warn:[config] Validation found 1 issue(s)')));
   assert.ok(
-    calls.some((entry) =>
-      entry.includes('notify:SubMiner:1 config validation issue(s) detected.'),
-    ),
+    calls.some((entry) => entry.includes('notify:SubMiner:1 config validation issue(s) detected.')),
   );
   assert.ok(calls.some((entry) => entry.includes('1. ankiConnect.pollingRate: must be >= 50')));
   assert.ok(calls.includes('hotReload:start'));
@@ -79,6 +74,9 @@ test('createReloadConfigHandler fails startup for parse errors', () => {
   assert.throws(() => reloadConfig(), /Failed to parse config file at:/);
   assert.equal(process.exitCode, 1);
   assert.ok(calls.some((entry) => entry.startsWith('error:Failed to parse config file at:')));
+  assert.ok(calls.some((entry) => entry.includes('/tmp/config.jsonc')));
+  assert.ok(calls.some((entry) => entry.includes('Error: unexpected token')));
+  assert.ok(calls.some((entry) => entry.includes('Fix the config file and restart SubMiner.')));
   assert.ok(
     calls.some((entry) =>
       entry.startsWith('dialog:SubMiner config parse error:Failed to parse config file at:'),

src/main/runtime/startup-config.ts

@@ -1,5 +1,6 @@
 import type { ConfigValidationWarning } from '../../types';
 import {
+  buildConfigParseErrorDetails,
   buildConfigWarningNotificationBody,
   buildConfigWarningSummary,
   failStartupFromConfig,
@@ -48,7 +49,7 @@ export function createReloadConfigHandler(deps: ReloadConfigRuntimeDeps): () =>
     if (!result.ok) {
       failStartupFromConfig(
         'SubMiner config parse error',
-        `Failed to parse config file at:\n${result.path}\n\nError: ${result.error}\n\nFix the config file and restart SubMiner.`,
+        buildConfigParseErrorDetails(result.path, result.error),
         deps.failHandlers,
       );
     }