Surface unreadable vector stores as a repairable failure

app/MindWork AI Studio/Tools/Services/RustService.Databases.cs

@@ -1,7 +1,18 @@
+using AIStudio.Tools.Databases.VectorStore;
+
 namespace AIStudio.Tools.Services;
 
 public sealed partial class RustService
 {
+    /// <summary>
+    /// The issue code the Rust runtime sends when a vector store is there, but cannot be opened.
+    /// </summary>
+    /// <remarks>
+    /// Mirrors ISSUE_CODE_STORE_UNREADABLE in runtime/src/qdrant_edge_database.rs. Reading the code
+    /// rather than the message is what keeps a reworded message on the Rust side harmless here.
+    /// </remarks>
+    private const string ISSUE_CODE_STORE_UNREADABLE = "store-unreadable";
+
     public async Task<TDatabaseInfo> GetDatabaseInfo<TDatabaseInfo>(
         string databaseName,
         string infoPath,
@@ -46,7 +57,7 @@ public sealed partial class RustService
 
         var operation = await response.Content.ReadFromJsonAsync<DatabaseOperationResponse>(this.jsonRustSerializerOptions, cts.Token);
         if (operation is not { Success: true })
-            throw new InvalidOperationException(operation?.Issue ?? $"The {databaseName} operation failed.");
+            throw CreateDatabaseException(operation?.Issue, operation?.IssueCode, $"The {databaseName} operation failed.");
     }
 
     public async Task<TResult?> ExecuteDatabaseQuery<TRequest, TResult>(string databaseName, string path, TRequest request, CancellationToken cancellationToken = default)
@@ -59,12 +70,31 @@ public sealed partial class RustService
 
         var operation = await response.Content.ReadFromJsonAsync<DatabaseQueryResponse<TResult>>(this.jsonRustSerializerOptions, cts.Token);
         if (operation is not { Success: true })
-            throw new InvalidOperationException(operation?.Issue ?? $"The {databaseName} query failed.");
+            throw CreateDatabaseException(operation?.Issue, operation?.IssueCode, $"The {databaseName} query failed.");
 
         return operation.Data;
     }
 
-    private sealed record DatabaseOperationResponse(bool Success, string Issue);
+    /// <summary>
+    /// Turns a failed database response into the exception which fits its issue code.
+    /// </summary>
+    /// <remarks>
+    /// Almost every failure says all it has to say in its message. A store which cannot be opened is
+    /// the exception: the only way out of it is a rebuild which costs the user money and time, so it
+    /// gets a type of its own and reaches the places which can offer that rebuild instead of
+    /// starting it unasked.
+    /// </remarks>
+    private static Exception CreateDatabaseException(string? issue, string? issueCode, string fallbackMessage)
+    {
+        var message = string.IsNullOrWhiteSpace(issue) ? fallbackMessage : issue;
+        return issueCode switch
+        {
+            ISSUE_CODE_STORE_UNREADABLE => new VectorStoreUnreadableException(message),
+            _ => new InvalidOperationException(message),
+        };
+    }
 
-    private sealed record DatabaseQueryResponse<TResult>(bool Success, string Issue, TResult? Data);
+    private sealed record DatabaseOperationResponse(bool Success, string Issue, string IssueCode);
+
+    private sealed record DatabaseQueryResponse<TResult>(bool Success, string Issue, string IssueCode, TResult? Data);
 }