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by ahartmetz 478 days ago
I have found that whatever my Yocto question is, reading (edit: bitbake -e and) 1-3 pages of pretty simple recipe and / or Bitbake code (Python) gives me the answer. Apparently, none of the people who complain have gotten far enough to run into the real problem... Bitbake is a shitty build system. Its dependency modeling is incomplete, so if you change some variable that influences many packages, you have to manually rebuild them. I just resorted to rebuilding everything after making that kind of change.
1 comments
IshKebab 478 days ago
Ha kind of ironic that there's a comment above that says this is an advantage over Buildroot.

In my opinion the task Yocto and Buildroot do means it is impossible to have reliable incremental builds. They're simply wrangling too many other unreliable build systems (autoconf, make, etc.). For example OpenSBI's Make based system doesn't do incremental builds correctly. I always have to build from scratch.

The only way it could really work reliably is if everything it builds used Bazel or one of its brethren.

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ahartmetz 478 days ago
At a client they use an obscure system called e2factory to build images and that one does model dependencies correctly. It creates a little chroot environment for every package build and errs on the side of rebuilding if in doubt. It's probably less flexible than Bitbake with Yocto, but incremental builds totally work. You might need some all-encompassing integration to get more fine-grained dependencies, but tracking what goes into a build is possible with standard build systems (mainly autoconf / make and CMake / Ninja in this case).
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IshKebab 478 days ago
That sounds like a good design.
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ahartmetz 478 days ago
Well, it has downsides, too - one needs to specify all dependencies for every package. That includes transitive dependencies, so some of these dependency lists look pretty weird. "I need video codecs to build the mouse driver?!" (not a true example, but along these lines)

But with that information, everything that goes into a package goes into the build signature. Environment variables and all.

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