The magic is installing module-build-macros. That package delivers RPM macros specified in buildopts section of a modulemd YAML file of a module the linked root.log is part of.

> But it never worked. Even adding 'perl_bootstrap 1' somewhere to /etc/rpm/macros does not work

Note, as I wrote above, simulating module-build-macros does not work, for some reason. Seems like a separate bug.

Anyway, it would be nice to use dnf builddep "--define" as a second option.

We add the macro into rpm using following code:

        for macro in self.opts.define:
            rpm.addMacro(macro[0], macro[1])

Therefore I am still not convinced if it is a bug or not.

An SRPM records its build dependencies as normal "requires".  When dnf-builddep(8) runs against an SRPM, it looks at those (see "rpm -qR perl-XXXXX.src.rpm").  Passing a --define to dnf-builddep won't change anything since the SRPM is already built.

You need to either rebuild the SRPM with rpmbuild(8) and pass it the desired --define, or install the existing SRPM ("rpm -i perl-XXXXX.src.rpm") first and then run dnf-builddep on the SPEC file (by default at ~/rpmbuild/SPECS/*.spec) in which case passing the --define would work.

Here's a simple SPEC to demonstrate this:

Name: foo
Version: 1
Release: 1%{?dist}
Summary: Foo package

License: GPL

%if %{defined bar}
BuildRequires: bar
%endif

%description
%{summary}.

%prep
%build
%install
%files

$ rpmbuild -bs foo.spec
[...]
$ rpm -qR /path/to/foo.srpm | grep bar
$ rpmbuild -bs --define "bar 1" foo.spec
[...]
$ rpm -qR /path/to/foo.srpm | grep bar
bar

The difference between the SRPM and SPEC variants with dnf-builddep was also recently discussed here: https://bugzilla.redhat.com/show_bug.cgi?id=2087703

Thank you very much Michal for your expertise. I am proposing to only add a note in documentation that define is not applied to srpm arguments.

Please, consider printing also some warning message if --define is used with src.rpm

A note was added to the man page and also warning is shown when using -D or --define with source rpm files.

Following PRs were queued to fix this:

fix:   https://github.com/rpm-software-management/dnf-plugins-core/pull/461
tests: https://github.com/rpm-software-management/ci-dnf-stack/pull/1142

Cloned into RHEL9 ticket https://bugzilla.redhat.com/show_bug.cgi?id=2077820.

(In reply to Jan Kolarik from comment #10)
> Cloned into RHEL9 ticket https://bugzilla.redhat.com/show_bug.cgi?id=2077820.

Sorry, wrong link. This is RHEL9 clone: https://bugzilla.redhat.com/show_bug.cgi?id=2121655

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (dnf-plugins-core bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:2975