Add default runners to west config

[glenn-andrews]

Is your enhancement proposal related to a problem? Please describe.
If you do not have the same runner on your board as the default in board.cmake you need to supply the alternative each time.

Describe the solution you'd like

1. west config options to set the default west flash and west debug runners that override those in board.cmake.
2. Supplying a --runner option to the west command would override the default, as it does for the default in board.cmake.
3. Setting the configuration option to default (or the option being missing) would revert to the default in board.cmake.

Describe alternatives you've considered
Different defaults per board would be nice, but hugely complicated to maintain and administer.

Additional context
Prompted by #75284 as it changes the runner, and anyone who does not download the ST software will have to add --runner openocd to their commands.

[henrikbrixandersen]

Do you know you can set -DBOARD_FLASH_RUNNER=... and/or -DBOARD_DEBUG_RUNNER=... when invoking west?

[pdgendt]

The proposed west aliases in zephyrproject-rtos/west#716 can be useful in this case too:

west config alias.flash "flash --runner=openocd"
west config alias.debug "debug --runner=openocd"

[glenn-andrews]

The proposed west aliases in zephyrproject-rtos/west#716 can be useful in this case too:

west config alias.flash "flash --runner=openocd"
west config alias.debug "debug --runner=openocd"

That would do nicely.

Can you override the alias?

[glenn-andrews]

Do you know you can set -DBOARD_FLASH_RUNNER=... and/or -DBOARD_DEBUG_RUNNER=... when invoking west?

That seems to just move the problem from having to remember to set it during debug to having to remember to set it during build.

I'm thinking of a situation where I'm working in an STM32 shop and in my daily life I'll always be using a specific tool, or I'm a student with an STM32 development board and don't want to remember specify the assignment-recommended runner for every exercise.

In these situations you want a set-it-and-forget it option for 99% of your work, with an easy override for when you need something different.

[pdgendt]

Can you override the alias?

What do you mean? You can override a command with an alias, if that is what you mean.

[pdgendt]

To try it out:

$ pip uninstall west
$ pip install https://github.com/zephyrproject-rtos/west/archive/pull/716/head.zip

[glenn-andrews]

Can you override the alias?

What do you mean? You can override a command with an alias, if that is what you mean.

I mean if I did west config alias.debug "debug --runner=openocd" but then for just one test needed to use J-Link, could I do west debug --runner=jlink or would the alias expand to west debug --runner=openocd --runner=jlinkand break because of two runners specified?

[pdgendt]

I mean if I did west config alias.debug "debug --runner=openocd" but then for just one test needed to use J-Link, could I do west debug --runner=jlink or would the alias expand to west debug --runner=openocd --runner=jlinkand break because of two runners specified?

It will expand to west debug --runner=openocd --runner=jlink which should actually work.