What causes a Sokoban corner-deadlock not being detected?

The game never tests whether a non-goal crate has been pushed against two perpendicular walls, so an unsolvable corner deadlock goes unflagged and the player keeps playing a dead level.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Sokoban Not Detecting a Crate Pushed Into a Corner Deadlock

Quick answer: After each push, check whether the moved crate sits on a non-goal cell with walls on two adjacent perpendicular sides; if so, mark the level deadlocked and offer undo or restart.

A crate shoved into a corner can never be moved again, soft-locking the level. Players often do not notice until much later. A cheap corner-deadlock check after each push catches the most common case immediately.

How to fix it

1. Test for a corner after each push

If the pushed crate is not on a goal and has a wall both horizontally and vertically adjacent (e.g. wall left and wall up), it is permanently stuck.

2. Surface the deadlock to the player

When a corner deadlock is detected, show a non-blocking prompt offering Undo or Restart so the player is not stranded in an unwinnable state.

3. Extend to wall-line deadlocks later

A crate against a wall with no goal anywhere along that wall is also dead. Add this as a second pass once the corner case is solid.

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 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.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.