Card Filter + Text Search Combination Bug

Summary

When combining set filters (Advanced Filters) with a text search in the deck builder collection, the game returns 0 results even though matching cards exist. This is a game-side bug — the mod correctly reads whatever cards the game provides, but the game’s card pool filtering logic fails when both filters are active simultaneously.

Reproduction Steps

  1. Open deck builder, navigate to collection
  2. Enable crafting toggle (to see unowned cards too)
  3. Search for “brand” — finds 4 cards including “Brandende Welle”
  4. Open Advanced Filters, enable Avatar set filter(s)
  5. Confirm filters — search field still shows “brand”
  6. Result: 0 cards displayed (expected: Brandende Welle)
  7. Clear the search text — Avatar cards now appear (8+ cards)
  8. Re-search “brand” — 0 cards again

Investigation Timeline

Session 1: Initial Discovery (12:54 - 12:56)

12:54:51  Deck builder opened, collection visible
12:55:07  Craft ON, search "brand" → 4 cards found:
          - Brandende Welle (Brandende_Welle)
          - Brandungsmaschine
          - Brandende Flutwelle
          - Goblin-Brandbombe
12:55:18  Opens Advanced Filters popup (114 elements, 4 rows)
12:55:26  Avatar Extra set toggle activated (ON)
12:55:28  Avatar base set toggle activated (ON)
12:55:32  OK pressed to apply filters → 0 collection cards
12:55:47  Search "brand" re-submitted
          Log: "Search rescan pool: 0 -> 0"
12:56:05  Search "well" submitted
          Log: "Search rescan pool: 0 -> 0"
12:56:18  Search cleared (empty)
          Log: "Search rescan pool: 0 -> 8"
          → 8 Avatar cards now visible (all creatures):
            Gran Gran, Tigerrobbe, Koh der Gesichterdieb,
            Suki der Kyoshi-Krieger, Zuko der Prinz,
            etc.

Key observation: Set filter alone works (8 cards). Text search alone works (4 cards including Brandende Welle). Combined: 0 cards.

Session 2: ExpansionCode Diagnostic (13:20 - 13:22)

Added debug logging to CardModelProvider.ExtractCardInfo() to verify Brandende Welle’s set code matches other Avatar cards.

Debug Logging Code

Added to src/Core/Services/CardModelProvider.cs at line ~1858 (within ExtractCardInfo):

// Expansion/Set - try direct ExpansionCode, then Printing.ExpansionCode
string rawExpCode = null;
var expCode = GetModelPropertyValue(dataObj, objType, "ExpansionCode");
if (expCode is string expStr && !string.IsNullOrEmpty(expStr))
{
    rawExpCode = expStr;
    info.SetName = UITextExtractor.MapSetCodeToName(expStr);
}
else if (printing != null)
{
    var printExpProp = printing.GetType().GetProperty("ExpansionCode");
    if (printExpProp != null)
    {
        var printExpVal = printExpProp.GetValue(printing)?.ToString();
        if (!string.IsNullOrEmpty(printExpVal))
        {
            rawExpCode = printExpVal;
            info.SetName = UITextExtractor.MapSetCodeToName(printExpVal);
        }
    }
}
if (rawExpCode != null)
    MelonLogger.Msg($"[CardModelProvider] {info.Name}: ExpansionCode='{rawExpCode}' -> SetName='{info.SetName}'");

Raw ExpansionCode Output

With Avatar filter active and search cleared, scrolling through pages:

Brandende Welle:           ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Gran Gran:                 ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Tigerrobbe:                ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Koh der Gesichterdieb:     ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Suki der Kyoshi-Krieger:   ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Zuko der Prinz:            ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Aang der Avatar:           ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Katara:                    ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Sokka:                     ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Toph Beifong:              ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Iroh:                      ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Appa:                      ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Momo:                      ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Feuerlord Ozai:            ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Prinzessin Azula:          ExpansionCode='TLA' -> SetName='Magic: The Gathering | Avatar: The Last Airbender™'
Gedankenwirbel:            ExpansionCode='PZA' -> SetName='PZA' (no localization found)

Set codes discovered:

Conclusion

Brandende Welle has ExpansionCode=’TLA’ — identical to all other Avatar cards (Gran Gran, Tigerrobbe, etc.) that DO appear when the Avatar filter is active without text search.

This disproves the hypothesis that the card has a different set code. The bug is in the game’s internal filter combination logic: when both a set filter AND text search are active simultaneously, the card pool returns empty even though cards matching both criteria exist.

Game Types Investigated

SetMetadataProvider (Core.Shared.Code.CardFilters)

Manages set filter data. Key fields:

ClientSetMetadata (Core.Code.Collations)

Per-set metadata:

External Search Results

Searched for this bug in official Arena sources (March 2026):

Impact on Mod

The mod correctly handles this situation:

Workaround for Users