report if cash only exists in the portfolio, not at broker (probably 0)

src/analytics/reconcile/common.zig

@@ -307,6 +307,11 @@ pub fn compareAccounts(
         var brokerage_total: f64 = 0;
         var option_value_delta: f64 = 0;
         var has_discrepancies = false;
+        // Did the export carry a cash row for this account? A broker drops a
+        // money-market position from the export entirely once it reaches
+        // zero, and the comparison below is driven by brokerage rows - so
+        // without this we would never look at the account's cash at all.
+        var saw_cash_row = false;
 
         // Track which portfolio symbols we've matched
         var matched_symbols = std.StringHashMap(void).init(allocator);
@@ -347,6 +352,7 @@ pub fn compareAccounts(
             var cd_allowance: f64 = 0;
 
             if (bp.is_cash) {
+                saw_cash_row = true;
                 pf_shares = portfolio.cashForAccount(portfolio_acct_name.?);
                 pf_value = pf_shares;
             } else {
@@ -532,6 +538,43 @@ pub fn compareAccounts(
                     });
                 }
             }
+
+            // Cash the broker no longer reports.
+            //
+            // A money-market position is dropped from the export once it
+            // reaches zero, so an account can appear with holdings but no cash
+            // row. Because the comparison above iterates brokerage rows, "no
+            // row" silently meant "no comparison" - a portfolio cash lot could
+            // sit stale indefinitely while a stock or CD in the same situation
+            // was flagged by the sweeps above. Observed in the wild: a $39.08
+            // BrokerageLink cash lot survived three weekly reconciliations
+            // after the money had actually been invested.
+            //
+            // This reports the discrepancy; it deliberately does not assert
+            // the balance is zero. Absence is strong evidence, not proof, and
+            // `audit` exists to surface things for a human to decide.
+            if (!saw_cash_row) {
+                const pf_cash = portfolio.cashForAccount(pa);
+                if (@abs(pf_cash) > cash_tolerance) {
+                    portfolio_total += pf_cash;
+                    has_discrepancies = true;
+                    try comparisons.append(allocator, .{
+                        .symbol = "CASH",
+                        .portfolio_shares = pf_cash,
+                        .brokerage_shares = null,
+                        .portfolio_price = 1.0,
+                        .brokerage_price = null,
+                        .portfolio_value = pf_cash,
+                        .brokerage_value = null,
+                        .shares_delta = null,
+                        .value_delta = null,
+                        .is_cash = true,
+                        .is_option = false,
+                        .only_in_brokerage = false,
+                        .only_in_portfolio = true,
+                    });
+                }
+            }
         }
 
         try results.append(allocator, .{
@@ -1078,6 +1121,124 @@ test "compareAccounts: unmapped brokerage account is reported brokerage-only" {
     try std.testing.expectApproxEqAbs(@as(f64, 200), cmp.brokerage_price.?, 0.01);
 }
 
+test "compareAccounts: cash the broker no longer reports is flagged portfolio-only" {
+    const allocator = std.testing.allocator;
+
+    // The real BrokerageLink incident. The $39.08 money-market balance had
+    // already been invested, so Fidelity dropped the FDRXX row from the
+    // export entirely - a zero position isn't exported. The account still
+    // appears (it holds FDSCX), but with no cash row. Because the comparison
+    // is driven by brokerage rows, "no row" used to mean "no comparison", and
+    // the stale cash lot survived three weekly reconciliations unnoticed.
+    var lots = [_]portfolio_mod.Lot{
+        .{ .symbol = "FDRXX", .shares = 39.08, .open_date = Date.fromYmd(2026, 2, 26), .open_price = 1.0, .security_type = .cash, .account = "Sample 401k BL" },
+        .{ .symbol = "FDSCX", .shares = 3018.809, .open_date = Date.fromYmd(2026, 2, 26), .open_price = 33.82, .account = "Sample 401k BL" },
+    };
+    const portfolio = portfolio_mod.Portfolio{ .lots = &lots, .allocator = allocator };
+
+    // Export carries the holding but NO cash row.
+    var brokerage = [_]BrokeragePosition{
+        .{ .account_number = "1234", .account_name = "BrokerageLink", .symbol = "FDSCX", .description = "FIDELITY STOCK SELECTOR SMALL CAP", .quantity = 3018.809, .current_value = 152963.05, .cost_basis = 104700.15, .is_cash = false },
+    };
+
+    var entries = [_]analysis.AccountTaxEntry{
+        .{ .account = "Sample 401k BL", .tax_type = .traditional, .institution = "fidelity", .account_number = "1234" },
+    };
+    const acct_map = analysis.AccountMap{ .entries = &entries, .allocator = allocator };
+
+    var prices = std.StringHashMap(f64).init(allocator);
+    defer prices.deinit();
+    try prices.put("FDSCX", 50.67);
+
+    const results = try compareAccounts(allocator, portfolio, &brokerage, acct_map, "fidelity", prices, Date.fromYmd(2026, 8, 1));
+    defer {
+        for (results) |r| allocator.free(r.comparisons);
+        allocator.free(results);
+    }
+
+    try std.testing.expectEqual(@as(usize, 1), results.len);
+    try std.testing.expect(results[0].has_discrepancies);
+
+    var found = false;
+    for (results[0].comparisons) |cmp| {
+        if (!cmp.is_cash or !cmp.only_in_portfolio) continue;
+        found = true;
+        try std.testing.expectApproxEqAbs(@as(f64, 39.08), cmp.portfolio_value, 0.001);
+        try std.testing.expect(cmp.brokerage_value == null);
+        try std.testing.expect(cmp.brokerage_shares == null);
+    }
+    try std.testing.expect(found);
+}
+
+test "compareAccounts: an export cash row suppresses the portfolio-only cash flag" {
+    const allocator = std.testing.allocator;
+
+    // Same account, but the broker DOES report cash. The normal comparison
+    // path owns it; there must be no duplicate portfolio-only cash row.
+    var lots = [_]portfolio_mod.Lot{
+        .{ .symbol = "FDRXX", .shares = 39.08, .open_date = Date.fromYmd(2026, 2, 26), .open_price = 1.0, .security_type = .cash, .account = "Sample 401k BL" },
+    };
+    const portfolio = portfolio_mod.Portfolio{ .lots = &lots, .allocator = allocator };
+
+    var brokerage = [_]BrokeragePosition{
+        .{ .account_number = "1234", .account_name = "BrokerageLink", .symbol = "FDRXX", .description = "HELD IN MONEY MARKET", .quantity = null, .current_value = 39.08, .cost_basis = null, .is_cash = true },
+    };
+
+    var entries = [_]analysis.AccountTaxEntry{
+        .{ .account = "Sample 401k BL", .tax_type = .traditional, .institution = "fidelity", .account_number = "1234" },
+    };
+    const acct_map = analysis.AccountMap{ .entries = &entries, .allocator = allocator };
+
+    var prices = std.StringHashMap(f64).init(allocator);
+    defer prices.deinit();
+
+    const results = try compareAccounts(allocator, portfolio, &brokerage, acct_map, "fidelity", prices, Date.fromYmd(2026, 8, 1));
+    defer {
+        for (results) |r| allocator.free(r.comparisons);
+        allocator.free(results);
+    }
+
+    try std.testing.expectEqual(@as(usize, 1), results.len);
+    for (results[0].comparisons) |cmp| {
+        try std.testing.expect(!(cmp.is_cash and cmp.only_in_portfolio));
+    }
+    try std.testing.expect(!results[0].has_discrepancies);
+}
+
+test "compareAccounts: no cash row and no portfolio cash stays silent" {
+    const allocator = std.testing.allocator;
+
+    // Absence on both sides is agreement, not a discrepancy.
+    var lots = [_]portfolio_mod.Lot{
+        .{ .symbol = "FDSCX", .shares = 3018.809, .open_date = Date.fromYmd(2026, 2, 26), .open_price = 33.82, .account = "Sample 401k BL" },
+    };
+    const portfolio = portfolio_mod.Portfolio{ .lots = &lots, .allocator = allocator };
+
+    var brokerage = [_]BrokeragePosition{
+        .{ .account_number = "1234", .account_name = "BrokerageLink", .symbol = "FDSCX", .description = "FIDELITY STOCK SELECTOR SMALL CAP", .quantity = 3018.809, .current_value = 152963.05, .cost_basis = 104700.15, .is_cash = false },
+    };
+
+    var entries = [_]analysis.AccountTaxEntry{
+        .{ .account = "Sample 401k BL", .tax_type = .traditional, .institution = "fidelity", .account_number = "1234" },
+    };
+    const acct_map = analysis.AccountMap{ .entries = &entries, .allocator = allocator };
+
+    var prices = std.StringHashMap(f64).init(allocator);
+    defer prices.deinit();
+    try prices.put("FDSCX", 50.67);
+
+    const results = try compareAccounts(allocator, portfolio, &brokerage, acct_map, "fidelity", prices, Date.fromYmd(2026, 8, 1));
+    defer {
+        for (results) |r| allocator.free(r.comparisons);
+        allocator.free(results);
+    }
+
+    try std.testing.expectEqual(@as(usize, 1), results.len);
+    for (results[0].comparisons) |cmp| {
+        try std.testing.expect(!(cmp.is_cash and cmp.only_in_portfolio));
+    }
+}
+
 test "compareAccounts: portfolio-only stock position is flagged only_in_portfolio" {
     const allocator = std.testing.allocator;