rpi-base: filter None values from DTB boot files

[lhoward]

Filter None values from DTB boot files, to avoid errors expanding IMAGE_BOOT_FILES

[lhoward]

I don't really know Python, so not sure what it's about the version I've installed that caused this. It would be great if (after review) it could also be back-ported to the scarthgap branch.

[agherzan]

I don't really know Python, so not sure what it's about the version I've installed that caused this. It would be great if (after review) it could also be back-ported to the scarthgap branch.

Thanks for this. I would like to understand why this happened in the first place. Could you dump the environment and check the value there? Also, a fix need to firstly land in master (and you can follow up with a cherry pick PR in other branches).

[lhoward]

Note to self: a colleague suggested

⁠ return ' '.join(x for x in (transform(dtb) for dtb in alldtbs.split(' ') if dtb) if x is not None) ⁠

would be more idiomatic

[lhoward]

I'll rerun the build without the patch when I'm at my desk, but my hunch is that the whitespaces in IMAGE_BOOT_FILES are being expanded split to None (at least on my system).

[lhoward]

Error I saw was:

ERROR: ExpansionError during parsing /home/lukeh/CVSRoot/padl/inferno/build/xebros/meta/recipes-core/images/core-image-minimal.bb
bb.data_smart.ExpansionError: Failure expanding variable IMAGE_BOOT_FILES, expression was bootfiles/*                  ${@make_dtb_boot_files(d)}                   	Image u-boot.bin;kernel8.img boot.scr 	                   which triggered exception TypeError: sequence item 59: expected str instance, NoneType found
The variable dependency chain for the failure is: IMAGE_BOOT_FILES

I don't know enough about BitBake to know how to dump more...