I checked Squeak. All my examples work consistently there: UnhandledError handler is always triggered.

Even more: signalling new error from the handler block passes it from the original signallerContext:

[

[ 1/0 ] on: MyTestError do: [ :e | self halt ]

��] on: ZeroDivide do: [ :z | MyTestError signal ]

This code halts in Squeak.

Context>>handleSignal: exception

"Sent to handler (on:do:) contexts only.�� If my exception class (first arg) handles exception

and the handler is active then execute my handle block (second arg), otherwise forward

this message to the next handler context.�� If none left, execute exception's defaultAction

(see nil>>handleSignal:)."

| handlerActive val |

"If the context has been returned from the handlerActive temp var may not be accessible."

handlerActive := stackp >= 3 and: [(self tempAt: 3) == true].

(((self tempAt: 1) handles: exception) and: [handlerActive]) ifFalse:

[^self nextHandlerContext handleSignal: exception].

exception privHandlerContext: self contextTag.

self tempAt: 3 put: false. ��"disable self while executing handle block"

val := [(self tempAt: 2) cull: exception]

ensure: [self tempAt: 3 put: true].

self return: val ��"return from self if not otherwise directed in handle block"