[BUG] G26 mesh_index_pair location may be used uninitialized in this function

[classicrocker883]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

G26_MESH_VALIDATION

• Marlin\src\gcode\bedlevel\G26.cpp
  mesh_index_pair location;

Marlin\src\gcode\bedlevel\G26.cpp:717:19: note: '*((void*)& location +1)' was declared here
'location.mesh_index_pair::pos.XYval<signed char>::<anonymous>.XYval<signed char>::<unnamed union>::<anonymous>.XYval<signed char>::<unnamed union>::<unnamed struct>::x'
was declared here

  717 |   mesh_index_pair location;

---

• Marlin\src\lcd\extui\ui_api.h
  inline void onMeshUpdate(const xy_int8_t &pos, probe_state_t state) { onMeshUpdate(pos.x, pos.y, state); }

Marlin\src\gcode\bedlevel\../../lcd/extui/ui_api.h:261:89: warning: '*((void*)& location +1)' may be used uninitialized in this function [-Wmaybe-uninitialized]
'location.mesh_index_pair::pos.XYval<signed char>::<anonymous>.XYval<signed char>::<unnamed union>::<anonymous>.XYval<signed char>::<unnamed union>::<unnamed struct>::x'
may be used uninitialized in this function [-Wmaybe-uninitialized]
  261 |       inline void onMeshUpdate(const xy_int8_t &pos, probe_state_t state) { onMeshUpdate(pos.x, pos.y, state); }

This may be related to having EXTENSIBLE_UI (ProUI) because of extui/ui_api.h

Bug Timeline

No response

Expected behavior

No warnings

Actual behavior

Warnings (see description)

Steps to Reproduce

1. Load configs (can be any typical)
2. Used EXTENSIBLE_UI display type - DWIN_LCD_PROUI (haven't tried any other)
3. Have G26_MESH_VALIDATION enabled

Version of Marlin Firmware

bugfix-2.1.x

Printer model

Voxelab Aquila

Electronics

No response

LCD/Controller

No response

Other add-ons

No response

Bed Leveling

UBL Bilinear mesh

Your Slicer

None

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Configs-UBL.zip

I tried to initialize mesh_index_pair location in G26.cpp to something like = {0, 0} or = {}, and recieved these errors:

Marlin\src\gcode\bedlevel\G26.cpp:849:3: error: jump to label 'LEAVE'
  849 |   LEAVE: 
Marlin\src\gcode\bedlevel\G26.cpp:675:60: note:   from here
  675 |   if (g26.prime_flag && g26.prime_nozzle() != G26_OK) goto LEAVE;