chore(web): Improve error messages for file loading errors

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Added support for arbitrary user IDs required for OpenShift. [#658](https://github.com/sourcebot-dev/sourcebot/pull/658) 
 
+### Updated
+- Improved error messages in file source api. [#665](https://github.com/sourcebot-dev/sourcebot/pull/665)
+
 ## [4.10.2] - 2025-12-04
 
 ### Fixed

packages/web/src/actions.ts

@@ -38,8 +38,8 @@ const auditService = getAuditService();
 /**
  * "Service Error Wrapper".
  * 
- * Captures any thrown exceptions and converts them to a unexpected
- * service error. Also logs them with Sentry.
+ * Captures any thrown exceptions, logs them to the console and Sentry,
+ * and returns a generic unexpected service error.
  */
 export const sew = async <T>(fn: () => Promise<T>): Promise<T | ServiceError> => {
     try {
@@ -52,10 +52,6 @@ export const sew = async <T>(fn: () => Promise<T>): Promise<T | ServiceError> =>
             return e.serviceError;
         }
 
-        if (e instanceof Error) {
-            return unexpectedError(e.message);
-        }
-
         return unexpectedError(`An unexpected error occurred. Please try again later.`);
     }
 }

packages/web/src/app/[domain]/browse/[...path]/components/codePreviewPanel.tsx

@@ -22,8 +22,12 @@ export const CodePreviewPanel = async ({ path, repoName, revisionName }: CodePre
         getRepoInfoByName(repoName),
     ]);
 
-    if (isServiceError(fileSourceResponse) || isServiceError(repoInfoResponse)) {
-        return <div>Error loading file source</div>
+    if (isServiceError(fileSourceResponse)) {
+        return <div>Error loading file source: {fileSourceResponse.message}</div>
+    }
+
+    if (isServiceError(repoInfoResponse)) {
+        return <div>Error loading repo info: {repoInfoResponse.message}</div>
     }
 
     const codeHostInfo = getCodeHostInfoForRepo({