Steps to reproduce:

Debug it:

self halt.

Inspect the Debugger model and do it:

(RunArray runs: #(2 1 1 3 3 2 1 4) values: #(#stepInto #stepOver #stepInto #stepOver #stepInto #stepOver #stepInto #stepOver))

do: [:each | self in: each].

Expected behavior:

The debugger shows the last step of UnhandledError class>>signalForException:.

Actual behavior:

A second debugger appears on the same process, showing UndefinedObject(Object)>>halt.

Notes:

None of my two proposals on how to fix the infinite debugger chains affects this behavior. There must be some other magic ...

Best,

Christoph