[BUG] LEVEL_BED_CORNERS UI quits early without input

[Knifa]

Bug Description

When using LEVEL_BED_CORNERS on bugfix-2.0.x (852a8d6685ec1137eb65e78fa748cae41fbd36b), the UI quits out early without pressing Done.

My Configurations

config.zip

Steps to Reproduce

1. Go to Motion > Level Bed Corners
2. Wait 5-10s. Don't do anything.

Expected behavior: [What you expect to happen]

I should be able to proceed through the corner steps indefinitely, as on 2.0.5.3.

Actual behavior: [What actually happens]

The UI exits suddenly without pressing Done.

Additional Information

This is on an Ender 3 with an SKR Mini E3 v1.2. It works OK on 2.0.5.3!

[swilkens]

I can confirm this, I see the same behaviour.

[Knifa]

A new macro was added around deferring the status screen ten days ago --- maybe it's not working as expected? Will try the commit before this one. https://github.com/MarlinFirmware/Marlin/commit/c536b8de629807b489f054051bb120457f112a11 is the commit that added it. https://github.com/MarlinFirmware/Marlin/blame/bugfix-2.0.x/Marlin/src/lcd/ultralcd.h#L511

FORCE_INLINE static void defer_status_screen(const bool defer=true) {
    TERN(LCD_TIMEOUT_TO_STATUS, defer_return_to_status = defer, UNUSED(defer));
}

previously just used #if. The TERN macro is so hard to follow! I can't make heads or tails of it.

[Knifa]

Yes, reverting this bit of code to how it was in the prior commit i.e.:

    FORCE_INLINE static void defer_status_screen(const bool defer=true) {
      #if LCD_TIMEOUT_TO_STATUS
        defer_return_to_status = defer;
      #else
        UNUSED(defer);
      #endif
    }

solves the issue.

Something is not right with TERN --- perhaps it is because LCD_TIMEOUT_TO_STATUS has a value rather than just being empty? I can't understand the macro chain at all so I'm stuck on how to fix it as intended.

I had a play around with the macros on Compile Explorer and it seems to evaluate the expression regardless as to whether or not LCD_TIMEOUT_TO_STATUS is present. Might be a Compile Explorer issue though.

[Knifa]

OK --- with more fanangling in Compiler Explorer, it seems that the macro only works if the define has no value, which LCD_TIMEOUT_TO_STATUS does.

Does this even need checked? LCD_TIMEOUT_TO_STATUS is always set in Conditionals_post.h so it should always be around.

[swilkens]

previously just used #if. The TERN macro is so hard to follow! I can't make heads or tails of it.

I would agree, the code readability didn't improve with this change. Additionally, it seems some expansion is causing unexpected consequences like this one.

[Knifa]

Fixed in https://github.com/MarlinFirmware/Marlin/commit/7c26a54d3f2434c4d578f58af011a76dd298d4e3.

[swilkens]

I can confirm the fix works, bed corner menu now properly remains

[github-actions[bot]]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.