[Bug] Post-QMK update, split keyboard does not compile "MATRIX_COLS is inconsistent with the size of MATRIX_COL_PINS"

[datapaganism]

I have just update QMK and decided to recompile my firmware.

I have a split design I have been working on and I have successfully compiled the same code previously and even flashed it.

My compiler issue is relating to the COL_PINS since the the split on my keyboard is not symmetrical (custom 75% layout).

Describe the Bug

My config code is this

#define MATRIX_ROWS 12
#define MATRIX_COLS 9

#define SOFT_SERIAL_PIN D3
#define SPLIT_LAYER_STATE_ENABLE
#define SPLIT_MODS_ENABLE

#define MATRIX_ROW_PINS { D4, C6, D7, E6, B4, B5 }
#define MATRIX_ROW_PINS_RIGHT { D0, D4, C6 , D7, E6, B4}

#define MATRIX_COL_PINS { B6, B2, B3, B1, F7, F6, F5 }
#define MATRIX_COL_PINS_RIGHT { B5, F4, F5, F6, F7, B1, B3, B2, B6 }

#define UNUSED_PINS
#define SPLIT_HAND_PIN D2
#define MASTER_RIGHT

#define SPLIT_USB_DETECT

The error that appears is complaining that COL_PINS (left) is 7 when it is configured to be 9, I have no idea how to add dummy fake pins to pad out the left side of the COL_PINS.

But this has worked perfectly before.

System Information

• Keyboard: Custom
  • Revision (if applicable):
• Operating system: manjaro
• AVR GCC version: 11.1.0

• ARM GCC version: 11.1.0

• QMK Firmware version: 0.14.29

• Any keyboard related software installed?
  • AutoHotKey
  • Karabiner
  • Other:

Additional Context

[sigprof]

You need to pad MATRIX_COL_PINS with NO_PIN (the new matrix scanning code supports that value properly by ignoring the corresponding column).

[datapaganism]

Thanks, I didn't catch that part in the docs (was reading the beta docs, but I would say NO_PIN would be a good mention at
https://docs.qmk.fm/#/feature_split_keyboard)

However that has spawned a new error down the line, I am using just serial, I feel like its quick fix but I can't figure it out

make[1]: *** No rule to make target 'drivers/avr/i2c_master.c', needed by '.build/obj_afk79s_default/i2c_master.o'.  Stop.

[sigprof]

Full support for NO_PIN was added in #12238 (before that change NO_PIN could be used only with DIRECT_PINS); however, it seems that the documentation was never updated to reflect that.

I2C driver files were relocated in #13894; you may need to run qmk clean to remove references to the old path from intermediate build files.

[datapaganism]

Thank you very much, take my issue as a request to update the documentation since I was totally lost with the new QMK version. People updating their firmware will have issues if the docs aren't to scratch.