Setting `zephyr.base` variable breaks parallel builds

I’m attempting to run multiple west build commands in parallel (to save some time used by cmake). This breaks randomly with corrupted .west/config file. I tracked this down to this line:

https://github.com/zephyrproject-rtos/west/blob/618020d1979d07003d6df40ce59b413785ce3015/src/west/app/main.py#L692

Here multiple processes may attempt to write to the same file at the same time in my scenario. It would be good to get rid of this. Right now one have to run a zephyr-provided command with valid arguments before doing the build. west boards seems to work.

Note that I have ZEPHYR_BASE environment variable set during the build, but that does not prevent west from mangling the config file.

[tejlmand]

@tejlmand mainly because west seems to be an official way to build zephyr apps.

Thanks for the reason. It is correct that Zephyr docs are describing the build process using west and it is an easy way to get started with Zephyr.

But actually west is an optional (but very convenient tool), so there is no problem in using cmake directly, especially if it solves your problems.

That being said, west should still be fixed so that this issue can be fixed. (we would like to remove zephyr.base from Cmake, but currently we need west to be backward compatible.)

[tejlmand]

@mbolivar-nordic with Zephyr 2.7.0 LTS out, it now the time to remove this in west ? Users on older Zephyr (for example 1.14 LTS ) can manually set zephyr.base if they need it.

I believe we don’t need to set this value automatically anymore.