Replace fragile price change detection in Purchase.save() with a
lazy dirty flag approach. A pre_save/post_save signal pair detects
price/currency changes without extra DB queries, and convert_prices()
uses the flag to determine which purchases need conversion.
- Add needs_price_update BooleanField with db_index
- Add pre_save signal to store old price/currency values
- Add post_save signal to set needs_price_update=True when price/currency changes
- Simplify Purchase.save() to remove DB reload + comparison logic
- Remove price_or_currency_differ_from() method
- Update convert_prices() to filter on needs_price_update flag
- Extract _get_exchange_rate() and _save_converted_price() helpers
- Add tests for the new behavior
The `NameWithIcon()` function had a `platform` parameter that was immediately overwritten by `platform = None` and never used (dead code). The function mixed data lookup (database queries via IDs) with rendering, making it untestable.
**Fix**: Refactored `NameWithIcon()` to follow the `LinkedPurchase` pattern — accepts model objects (`Game`, `Session`) instead of IDs. Extracted `_resolve_name_with_icon()` helper for testable computation logic (name resolution, platform extraction, link creation). Fixed bug where `platform` was not extracted when `session` parameter was passed. Removed dead `platform` parameter from the public API. Updated all 3 production call sites (already using model objects). Added 10 unit tests for `_resolve_name_with_icon()` covering session override, custom names, linkify behavior, platform resolution, and edge cases. Updated 6 integration tests to use model-based parameters.
`attributes: list[HTMLAttribute] = []` and `children: list[HTMLTag] | HTMLTag = []` are a classic Python gotcha — the default is shared across all callers and could silently corrupt state if ever mutated in place. Changed 8 functions (`Component`, `Popover`, `A`, `Button`, `Div`, `Input`, `Form`, `Icon`) to use the `None` sentinel pattern, preventing future bugs and eliminating linter warnings.
Replaced single `url` parameter with explicit `url_name` (URL pattern name resolved via `reverse()`) and `href` (literal path). Fixes:
- Silent fallback (typos like `"ad_puchase"` silently became broken links) → now raises `NoReverseMatch` at render time
- `type(url) is str` gate → removed (implicit dual-mode eliminated entirely)
- Callable parameter (`url: Callable`) dead code → removed
- Implicit dual-mode (`url="name"` vs `url=reverse("name")`) → `url_name` vs `href` are now mutually exclusive params
- Inconsistent type annotation mixing `Callable` with string default → cleaned up
- Added `ValueError` when both `url_name` and `href` are provided
- Updated all 10 call sites across 6 view files and internal callers (`LinkedPurchase()`, `NameWithIcon()`)
lukas
