As the branch field has a default value "master", this default
not only applies when the dialog box for starting the manual
workflow is presented. But even if the prefilled branch field
is cleared, the default value also gets substituted when submitting.
In this case, when the commit and branch fields are mutually
exclusive, we can't easily have a default. Instead change the
uses of the fields, ignoring the branch field if the commit field
is filled.
If the dawidd6/action-download-artifact action would support
specifying either a commit or a branch in the same field, like
actions/checkout does, we wouldn't need this distinction at all;
this request is tracked upstream at
https://github.com/dawidd6/action-download-artifact/issues/242.
6b6b1240e2 tried to build a
multiplatform image, by building two images separately and pushing
them one at a time, with the same name (but with a different platform).
This doesn't work as expected; the last push for the image name
replaces earlier pushes. So depending on which push finishes
last, we'd end up with either an amd64 or arm64 image, but not
one that supports both.
Instead, push two separate images just with push-by-digest, and
then create the actual tag with "docker buildx imagetools create".
Alternatively, we could build all platform variants of the main
image with Dockerfile.toolchain, simplifying the setup significantly.
The contents of such a build is marginally different though, so
keep the amd64 image as it was, for now, compiled in that environment.
Martin Storsjö