Re: Conditional weak assignments behave unexpectedly

["Moessbauer, Felix" <felix.moessbauer@siemens.com>]

On Sun, 2023-04-23 at 07:48 +0000, 'Moessbauer, Felix' via isar-users
wrote:
> Dear developers,
> 
> I just stumbled upon the following pattern, which needs further
> investigation:
> 
> - use the qemuamd64 machine on debian-bullseye
> - define a custom WKS_FILE in local.conf
> 
> While the qemuamd64.conf file contains the following line:
> WKS_FILE:debian-bullseye ?= "sdimage-efi-btrfs"
> I expected that I'm able to override that unconditionally in the
> local.conf using: WKS_FILE = "foo.wks"
> 
> However, the final value of the WKS_FILE variable is "sdimage-efi-
> btrfs". In the bitbake documentation, I cannot find any example of
> combining weak assignments and overrides. However, the implementation
> seems to evaluate the weak assignment on the override first. Then,
> the
> WKS_FILE part from the local conf is evaluated and finally the
> WKS_FILE:debian-bullseye overrides what was in WKS_FILE. This
> suspicion
> is also backed by the following test:
> 
> local.conf: WKS_FILE:debian-bullseye = "foo.wks"
> Now, the final value of WKS_FILE is "foo.wks".
> 
> I'm unsure if that has ever been like that and was just unnoticed, or
> if the behavior change was introduced in bitbake 2.0.
> Anyways, we must not use overrides in combination with weak
> assignments. And we also need to fix that on the qemuamd64 machine
> config immediately (even if we loose some tests by doing that).
> Otherwise it is impossible to override the WKS_FILE of the qemuamd64
> machine.

I just checked where this pattern is used in meta and meta-isar. There
are quite some occurrences. However, all except for the WKS_FILE seem
to be never customized anyways. With ack and this regex, you can check
by yourself (also in downstream layers).

Felix

ack '[A-Z]+:[a-z0-9-]+\s*\?=' meta meta-isar/
meta/recipes-devtools/sbuild-chroot/sbuild-chroot-host.bb
21:SBUILD_CHROOT_PREINSTALL:riscv64 ?= " \

meta/conf/bitbake.conf
66:KERNEL_FILE:mipsel ?= "vmlinux"
67:KERNEL_FILE:riscv64 ?= "vmlinux"
68:KERNEL_FILE:arm64 ?= "vmlinux"

meta-isar/conf/machine/qemuarm64.conf
7:KERNEL_NAME:ubuntu-focal ?= "generic"

meta-isar/conf/machine/qemuamd64.conf
7:KERNEL_NAME:ubuntu-focal ?= "generic"
13:WKS_FILE:ubuntu-focal ?= "sdimage-efi-sd"
16:WKS_FILE:debian-bullseye ?= "sdimage-efi-btrfs"

meta-isar/conf/distro/ubuntu-focal.conf
13:DISTRO_APT_SOURCES:arm64 ?= "conf/distro/${BASE_DISTRO}-
${BASE_DISTRO_CODENAME}-ports.list"
14:HOST_DISTRO_APT_SOURCES:arm64 ?= "conf/distro/${HOST_DISTRO}.list
conf/distro/${HOST_DISTRO}-ports.list"

meta-isar/conf/distro/raspios-bullseye.conf
16:DISTRO_APT_SOURCES:arm64 ?= "conf/distro/raspios-bullseye-64.list"

> 
> Best regards,
> Felix
>