How to Fix a GameMaker ds_map Content Not Loading From JSON

Your item JSON loads but every field reads as undefined. GameMaker has two JSON paths with different output types, and mixing struct access with ds_map data fails. Pick one and match the accessors.

How to fix it

1. Prefer json_parse for structs

Use json_parse to get GameMaker structs and arrays, then read with dot/array syntax; it is simpler than ds_map and does not need manual destruction.

2. Match accessors to the type

If you use json_decode, the result is a ds_map; read nested values with ds_map_find_value and ds_list accessors, not struct dot syntax.

3. Check the root type

Before indexing, confirm whether your JSON root is an object or an array and read it accordingly; treating an array root as an object returns undefined.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every GameMaker error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.