I am trying to create a new set of Qt packages for an older version of Ubuntu (Focal Fossa). I am using a newer release of Ubuntu than the one I am creating packages for, so I am using pbuilder-dist which automates the creation of a chroot for the intended distribution. During this process, I have encountered a chicken and egg problem, where the qtbase ubuntu repo (that contains the necessary debian/control rules, etc) contains an optional requirement on Qt documentation tools, which themselves depend on the base packages. It appears this is normally worked around by specifying the nodoc debian build profile using the environment variable DEB_BUILD_PROFILES, which will skip these requirements when performing the pbuilder build, however it doesn't seem to work.
I see the logic in the pbuilder-dist implementation (filter_restriction_deps in /usr/lib/pbuilder/pbuilder-satisfydepends-funcs) that should be reading the environment variable and filtering out the dependencies that are marked !nodoc when nodoc is specified, but any means of me specifying DEB_BUILD_PROFILES seems to be ignored.
From poking around the various documentation for the debian packaging tools, there should be a way to specify this, but it eludes me. For the moment I have very crudely worked around this by just removing these optional dependencies from the build before issuing the pbuilder-dist command line.
Can someone inform me how I can pass a build profile specifier to pbuilder_dist?
To answer my own question, there is a --profiles option to pbuilder-dist which fulfills this task. Environment variables do not seem to pass onto the pbuilder command that pbuilder-dist runs, however the --profiles option does.
So, to solve this, I add --profiles nodoc on the command line for the pbuilder-dist command:
pbuilder-dist focal build --profiles nodoc ../qtbase-opensource-src_5.15.9+kkyz-0.1.2.dsc