1476667 - Step over should not take two steps to leave a function which has a return

Status: RESOLVED FIXED

(DevTools :: Debugger, enhancement, P3)

Description

[Jason Laster [:jlast]]

Currently step over stops twice at the end of functions with a return value. This is because the first pause is the onStep and the second is the onPop. We want to prevent the first one because it doesn't show the completion value and is redundant.


> function f() {
>   return 2;
> }  // <--- pauses twice here


This PR fixes that, but we should also in the engine so we do not need an empty point. https://github.com/devtools-html/debugger.html/pull/6660

Comment 1

[Logan Smyth [:loganfsmyth]]

Attachment: an example of the function end position causing unexpected jumps past the finally block

Here's an example where this behavior of jumping to the end causes unintuitive stepping behavior.

Comment 2

[Logan Smyth [:loganfsmyth]]

This is caused by the position being set at https://searchfox.org/mozilla-central/rev/c296d5b2391c8b37374b118180b64cca66c0aa16/js/src/frontend/BytecodeEmitter.cpp#6123

Comment 3

[Jason Laster [:jlast]]

I believe this is fixed.

Comment 4

[Logan Smyth [:loganfsmyth]]

Yeah, now that https://bugzilla.mozilla.org/show_bug.cgi?id=breakpoint-specificity limits the stepping locations, this weird bytecode position metadata isn't an issue for us.