refactor(pre-alpha): fail closed on historical preview fallbacks

2026-03-26 11:55:45 +01:00
parent 4eec0127da
commit f38d0a53a9
6 changed files with 85 additions and 47 deletions
--- a/app/pages/backtests.py
+++ b/app/pages/backtests.py
@@ -289,9 +289,9 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                        row_key="date",
                    ).classes("w-full")

-        def validate_current_scenario() -> str | None:
+        def validate_current_scenario(*, entry_spot: float | None = None) -> str | None:
            try:
-                service.run_read_only_scenario(
+                service.validate_preview_inputs(
                    symbol=str(symbol_input.value or ""),
                    start_date=parse_iso_date(start_input.value, "Start date"),
                    end_date=parse_iso_date(end_input.value, "End date"),
@@ -299,6 +299,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                    underlying_units=float(units_input.value or 0.0),
                    loan_amount=float(loan_input.value or 0.0),
                    margin_call_ltv=float(ltv_input.value or 0.0),
+                    entry_spot=entry_spot,
                )
            except (ValueError, KeyError) as exc:
                return str(exc)
@@ -320,12 +321,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
        def refresh_workspace_seeded_units() -> None:
            validation_label.set_text("")
            entry_spot, entry_error = derive_entry_spot()
-            if (
-                workspace_id
-                and config is not None
-                and config.gold_value is not None
-                and entry_spot is not None
-            ):
+            if workspace_id and config is not None and config.gold_value is not None and entry_spot is not None:
                units_input.value = asset_quantity_from_workspace_config(config, entry_spot=entry_spot, symbol="GLD")
                entry_spot_hint.set_text(f"Auto-derived entry spot: ${entry_spot:,.2f}")
            else:
@@ -335,7 +331,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                validation_label.set_text(entry_error)
                render_result_state("Scenario validation failed", entry_error, tone="warning")
                return
-            validation_error = validate_current_scenario()
+            validation_error = validate_current_scenario(entry_spot=entry_spot)
            if validation_error:
                validation_label.set_text(validation_error)
                render_result_state("Scenario validation failed", validation_error, tone="warning")
@@ -351,7 +347,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                validation_label.set_text(entry_error)
                render_result_state("Scenario validation failed", entry_error, tone="warning")
                return
-            validation_error = validate_current_scenario()
+            validation_error = validate_current_scenario(entry_spot=entry_spot)
            if validation_error:
                validation_label.set_text(validation_error)
                render_result_state("Scenario validation failed", validation_error, tone="warning")
@@ -371,12 +367,18 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                    margin_call_ltv=float(ltv_input.value or 0.0),
                )
            except (ValueError, KeyError) as exc:
-                render_seeded_summary(entry_spot=None, entry_spot_error=None)
+                entry_spot, entry_error = derive_entry_spot()
+                render_seeded_summary(entry_spot=entry_spot, entry_spot_error=entry_error)
+                if entry_spot is None:
+                    entry_spot_hint.set_text("Entry spot unavailable until the scenario dates are valid.")
                validation_label.set_text(str(exc))
                render_result_state("Scenario validation failed", str(exc), tone="warning")
                return
            except Exception:
-                render_seeded_summary(entry_spot=None, entry_spot_error=None)
+                entry_spot, entry_error = derive_entry_spot()
+                render_seeded_summary(entry_spot=entry_spot, entry_spot_error=entry_error)
+                if entry_spot is None:
+                    entry_spot_hint.set_text("Entry spot unavailable until the scenario dates are valid.")
                message = "Backtest failed. Please verify the scenario inputs and try again."
                logger.exception(
                    "Backtest page run failed for workspace=%s symbol=%s start=%s end=%s template=%s units=%s loan=%s margin_call_ltv=%s",
--- a/app/pages/event_comparison.py
+++ b/app/pages/event_comparison.py
@@ -203,13 +203,6 @@ def _render_event_comparison_page(workspace_id: str | None = None) -> None:
                    syncing_controls["value"] = False

            template_slugs = selected_template_slugs()
-            if not template_slugs:
-                template_slugs = tuple(service.default_template_selection(str(option["slug"])))
-                syncing_controls["value"] = True
-                try:
-                    template_select.value = list(template_slugs)
-                finally:
-                    syncing_controls["value"] = False

            try:
                preview_units = float(units_input.value or 0.0)
@@ -243,6 +236,21 @@ def _render_event_comparison_page(workspace_id: str | None = None) -> None:
                scenario_label.set_text(str(exc))
                render_selected_summary(entry_spot=None, entry_spot_error=str(exc))
                return str(exc)
+            except Exception:
+                logger.exception(
+                    "Event comparison preview failed for workspace=%s preset=%s templates=%s units=%s loan=%s margin_call_ltv=%s",
+                    workspace_id,
+                    preset_select.value,
+                    selected_template_slugs(),
+                    units_input.value,
+                    loan_input.value,
+                    ltv_input.value,
+                )
+                message = "Event comparison preview failed. Please verify the seeded inputs and try again."
+                metadata_label.set_text(f"Preset: {option['label']} — {option['description']}")
+                scenario_label.set_text(message)
+                render_selected_summary(entry_spot=None, entry_spot_error=message)
+                return message
            preset = service.event_preset_service.get_preset(str(option["slug"]))
            metadata_label.set_text(f"Preset: {option['label']} — {option['description']}")
            scenario_label.set_text(
@@ -261,15 +269,7 @@ def _render_event_comparison_page(workspace_id: str | None = None) -> None:
        def render_report() -> None:
            validation_label.set_text("")
            result_panel.clear()
-            option = preset_lookup.get(str(preset_select.value or ""))
            template_slugs = selected_template_slugs()
-            if option is not None and not template_slugs:
-                template_slugs = tuple(service.default_template_selection(str(option["slug"])))
-                syncing_controls["value"] = True
-                try:
-                    template_select.value = list(template_slugs)
-                finally:
-                    syncing_controls["value"] = False
            try:
                report = service.run_read_only_comparison(
                    preset_slug=str(preset_select.value or ""),
--- a/app/services/backtesting/ui_service.py
+++ b/app/services/backtesting/ui_service.py
@@ -98,7 +98,7 @@ class BacktestPageService:
            )
        return history[0].close

-    def run_read_only_scenario(
+    def validate_preview_inputs(
        self,
        *,
        symbol: str,
@@ -108,7 +108,8 @@ class BacktestPageService:
        underlying_units: float,
        loan_amount: float,
        margin_call_ltv: float,
-    ) -> BacktestPageRunResult:
+        entry_spot: float | None = None,
+    ) -> float:
        normalized_symbol = symbol.strip().upper()
        if not normalized_symbol:
            raise ValueError("Symbol is required")
@@ -125,9 +126,35 @@ class BacktestPageService:
        if not template_slug:
            raise ValueError("Template selection is required")

+        self.template_service.get_template(template_slug)
+        resolved_entry_spot = (
+            entry_spot if entry_spot is not None else self.derive_entry_spot(normalized_symbol, start_date, end_date)
+        )
+        _validate_initial_collateral(underlying_units, resolved_entry_spot, loan_amount)
+        return resolved_entry_spot
+
+    def run_read_only_scenario(
+        self,
+        *,
+        symbol: str,
+        start_date: date,
+        end_date: date,
+        template_slug: str,
+        underlying_units: float,
+        loan_amount: float,
+        margin_call_ltv: float,
+    ) -> BacktestPageRunResult:
+        normalized_symbol = symbol.strip().upper()
+        entry_spot = self.validate_preview_inputs(
+            symbol=normalized_symbol,
+            start_date=start_date,
+            end_date=end_date,
+            template_slug=template_slug,
+            underlying_units=underlying_units,
+            loan_amount=loan_amount,
+            margin_call_ltv=margin_call_ltv,
+        )
        template = self.template_service.get_template(template_slug)
-        entry_spot = self.derive_entry_spot(normalized_symbol, start_date, end_date)
-        _validate_initial_collateral(underlying_units, entry_spot, loan_amount)
        initial_portfolio = materialize_backtest_portfolio_state(
            symbol=normalized_symbol,
            underlying_units=underlying_units,
--- a/app/services/event_comparison_ui.py
+++ b/app/services/event_comparison_ui.py
@@ -114,6 +114,8 @@ class EventComparisonPageService:
        loan_amount: float,
        margin_call_ltv: float,
    ) -> BacktestScenario:
+        if not template_slugs:
+            raise ValueError("Select at least one strategy template.")
        try:
            scenario = self.comparison_service.preview_scenario_from_inputs(
                preset_slug=preset_slug,
@@ -147,6 +149,8 @@ class EventComparisonPageService:
    ) -> EventComparisonReport:
        if not preset_slug:
            raise ValueError("Preset selection is required")
+        if not template_slugs:
+            raise ValueError("Select at least one strategy template.")
        if underlying_units <= 0:
            raise ValueError("Underlying units must be positive")
        if loan_amount < 0:
@@ -162,7 +166,7 @@ class EventComparisonPageService:
        try:
            preview = self.comparison_service.preview_scenario_from_inputs(
                preset_slug=preset.slug,
-                template_slugs=tuple(template_slugs or preset.scenario_overrides.default_template_slugs),
+                template_slugs=template_slugs,
                underlying_units=underlying_units,
                loan_amount=loan_amount,
                margin_call_ltv=margin_call_ltv,
@@ -180,7 +184,7 @@ class EventComparisonPageService:
        _validate_initial_collateral(underlying_units, preview.initial_portfolio.entry_spot, loan_amount)
        return self.comparison_service.compare_event_from_inputs(
            preset_slug=preset.slug,
-            template_slugs=tuple(template_slugs or preset.scenario_overrides.default_template_slugs),
+            template_slugs=template_slugs,
            underlying_units=underlying_units,
            loan_amount=loan_amount,
            margin_call_ltv=margin_call_ltv,