PR O: convert BalanceDataset and BalanceSheetDataset to records

Both were constructor-initialised value carriers with read-only
consumers. Positional record syntax replaces the class + property +
ctor boilerplate; ViewService callers updated to PascalCase named
args to match the record-generated parameter names.

Rest of item 26 descoped: XmlSerializer needs mutable public
setters (value-equality on mutable data is a footgun) and has no
source generator without changing file format. See
IMPROVEMENT_PLAN.md for the full rationale.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

IMPROVEMENT_PLAN.md

@@ -110,3 +110,4 @@ Analysis and phased plan produced 2026-07-02. See conversation history for full
 - **PR L** — Phase 2 item 10: drop the hand-rolled `Copy(target)` methods from `Account`, `BookingRule`, `BookingText`, `SubClass`, and `SplitPredefinition`; keep only a `Transaction.Clone()` for defensive-copy needs in `GetTransaction` / `ViewService.WithDisplaySign`. Every `SaveXxx` now uses `FindIndex` → in-place replace (or `Add` for new entries), moving the two "hidden" defaults (`Account.Currency = "CHF"` when unset, `Transaction.BookingDate = ValueDate` when unset) into the corresponding `SaveXxx` method where they belong. Fixes a pre-existing bug: `Transaction.Copy` never copied `RelatedParty`, so update-saves silently dropped it. Added `PreserveRelatedPartyWhenRoundTrippingTransaction` and `DefaultBookingDateToValueDateWhenBookingDateIsUnset` as regression tests. 42 tests total.
 - **PR M** — Phase 2 item 18 (final slice): add `ILogger<ViewService>` and log a match-count summary from `MatchOpenBankTransactions` (`"Matched {Matched} of {Total} open bank transactions"`). Completes item 18 — statement imports (PR H), repository save failures (PR J), and match runs now all emit structured logs. Also removes a dead `ISettingsService` injection from `Home.razor.cs` (declared with `[Inject]` but never used anywhere in the file).
 - **PR N** — Small polish pass covering three long-noted rough edges from the original analysis: `ClassIds` becomes a `static class` (was instantiable); `Home.razor.cs` loses the redundant `loaded` guard in `OnInitializedAsync` (Blazor already runs that lifecycle hook once per component instance); the hardcoded `mandator = "Claudio Schaad"` in `SettingsService` moves to a `DefaultMandator` field on `SettingsDataset`, plumbed through `appsettings.Development.json`.
+- **PR O** — Phase 5 item 26 (partial): convert `BalanceDataset` and `BalanceSheetDataset` to positional records. Both were constructor-initialised value carriers with read-only usage. The rest of item 26 was descoped: the XML-serialised domain models (`Account`, `Transaction`, ...) need mutable public setters for `XmlSerializer`, and value-equality on mutable data is a footgun (hash changes on mutation); source-generated XML serialisers do not exist without switching file formats. `DataSerie` was already a record; `MessageDataset` has a real mutation method (`Add`) and stays a class; `AccountDataset` / `TransactionDataset` / `BookingRuleDataset` inherit from the mutable domain models and can't cleanly become records without a bigger refactor.

Schaad.Accounting.Common/Datasets/Reports/BalanceDataset.cs

@@ -1,23 +1,10 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 
 namespace Schaad.Accounting.Datasets.Reports
 {
-    public class BalanceDataset
+    public record BalanceDataset(
-    {
+        List<AccountDataset> ActivaAccountList,
-        public List<AccountDataset> ActivaAccountList { get; set; }
+        List<AccountDataset> PassivaAccountList,
-
+        decimal TotalActivaCHF,
-        public List<AccountDataset> PassivaAccountList { get; set; }
+        decimal TotalPassivaCHF);
-
+}
-        public decimal TotalActivaCHF { get; set; }
-
-        public decimal TotalPassivaCHF { get; set; }
-
-        public BalanceDataset(List<AccountDataset> activaAccountList, List<AccountDataset> passivaAccountList, decimal totalActivaCHF, decimal totalPassivaCHF)
-        {
-            ActivaAccountList = activaAccountList;
-            PassivaAccountList = passivaAccountList;
-            TotalActivaCHF = totalActivaCHF;
-            TotalPassivaCHF = totalPassivaCHF;
-        }
-    }
-}

Schaad.Accounting.Common/Datasets/Reports/BalanceSheetDataset.cs

@@ -1,29 +1,12 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 
 namespace Schaad.Accounting.Datasets.Reports
 {
-    public class BalanceSheetDataset
+    public record BalanceSheetDataset(
-    {
+        List<AccountDataset> ActivaAccountList,
-        public List<AccountDataset> ActivaAccountList { get; }
+        List<AccountDataset> IncomeAccountList,
-
+        List<AccountDataset> ExpensesAccountList,
-        public List<AccountDataset> IncomeAccountList { get; }
+        decimal ProfitCHF,
-
+        decimal LossCHF,
-        public List<AccountDataset> ExpensesAccountList { get; }
+        int Year);
-
+}
-        public decimal ProfitCHF { get; }
-
-        public decimal LossCHF { get; }
-
-        public int Year { get; }
-
-        public BalanceSheetDataset(List<AccountDataset> activaAccountList, List<AccountDataset> incomeAccountList, List<AccountDataset> expensesAccountList, decimal profitCHF, decimal lossCHF, int year)
-        {
-            ActivaAccountList = activaAccountList;
-            IncomeAccountList = incomeAccountList;
-            ExpensesAccountList = expensesAccountList;
-            ProfitCHF = profitCHF;
-            LossCHF = lossCHF;
-            Year = year;
-        }
-    }
-}

Schaad.Accounting.Services/ViewService.cs

@@ -96,14 +96,11 @@ namespace Schaad.Accounting.Services
         public BalanceDataset GetBalanceView()
         {
             var accountList = GetAccountViewList();
-            var balanceView = new BalanceDataset(
+            return new BalanceDataset(
-                    activaAccountList: accountList.Where(m => m.Class == ClassIds.Activa).ToList(),
+                ActivaAccountList: accountList.Where(m => m.Class == ClassIds.Activa).ToList(),
-                    passivaAccountList: accountList.Where(m => m.Class == ClassIds.Passiva).ToList(),
+                PassivaAccountList: accountList.Where(m => m.Class == ClassIds.Passiva).ToList(),
-                    totalActivaCHF: Math.Abs(accountList.Where(m => m.Class == ClassIds.Activa).Sum(m => m.BalanceCHF)),
+                TotalActivaCHF: Math.Abs(accountList.Where(m => m.Class == ClassIds.Activa).Sum(m => m.BalanceCHF)),
-                    totalPassivaCHF: Math.Abs(accountList.Where(m => m.Class == ClassIds.Passiva).Sum(m => m.BalanceCHF))
+                TotalPassivaCHF: Math.Abs(accountList.Where(m => m.Class == ClassIds.Passiva).Sum(m => m.BalanceCHF)));
-                );
-
-            return balanceView;
         }
 
         public BalanceSheetDataset GetBalanceSheetView(int year)
@@ -115,13 +112,12 @@ namespace Schaad.Accounting.Services
             var loss = Math.Abs(accountList.Where(m => m.Class == ClassIds.Expenses).Sum(m => m.BalanceCHF));
 
             var balanceView = new BalanceSheetDataset(
-                    activaAccountList: accountList.Where(m => m.Class == ClassIds.Activa).ToList(),
+                ActivaAccountList: accountList.Where(m => m.Class == ClassIds.Activa).ToList(),
-                    incomeAccountList: accountList.Where(m => m.Class == ClassIds.Income).ToList(),
+                IncomeAccountList: accountList.Where(m => m.Class == ClassIds.Income).ToList(),
-                    expensesAccountList: accountList.Where(m => m.Class == ClassIds.Expenses).ToList(),
+                ExpensesAccountList: accountList.Where(m => m.Class == ClassIds.Expenses).ToList(),
-                    profitCHF: profit,
+                ProfitCHF: profit,
-                    lossCHF: loss,
+                LossCHF: loss,
-                    year: year
+                Year: year);
-                );
 
             return balanceView;
         }