cmake - How does rpmbuild compute which fields to generate?

Question

When comparing different RPM files, I've noticed that not all of them expose the same header tags. So there must be some logic that activates/deactivates creation of some of them.

One example is the build time and host. I've stumbled upon two RPM specs. Neither mentions anything that looks at all like a specification or switch to provide the information. Still, one of them is generated with Build Time and Build Host fields, the other isn't (I am not permitted to post either one).

I am aware of the new _buildhost macro. The RPM version used to generate both is insufficient to use it. Both packages get created from a list of Sources, as far as I can see. The one that doesn't display the build information gets built using CMake/CPack, the other uses rpmbuild directly, that's the only information I have about serious difference.

Both are defined as Group: AddOn. So far, I haven't found any remotely definite resources about what groups are valid, or their meanings. Only thing I found was the list of deprecated groups in Fedora. I'd be more interested in a list of supported ones, but wasn't successful so far.

Resources I've found until now (omitting the pointless ones): Max RPM Package Building Page, RedHat blog-ish tutorial, The RPM build guide, The actual RPM tags documentation, The RPM packaging guide

Unfortunately, none of the above provide the information I'm looking for.

"Give a man a fish" question: How can I suppress creation of Build Time or Build Host in rpm 4.11, be it in spec syntax or in usage of rpmbuild?

"Teach a man how to fish" question: Is there any documentation about what header tags get created with which settings?

question from:https://stackoverflow.com/questions/65909759/how-does-rpmbuild-compute-which-fields-to-generate

Answer 1

You can use Mock for building rpm (recommended anyway). and use config_opts['hostname'] = 'my.own.hostname'. Mock will call sethostname() in the chroot. This is the only way how to do it AFAIK.

rpmbuild should honor SOURCE_DATE_EPOCH - but I never used it. You can set environment variable using: config_opts['environment']['SOURCE_DATE_EPOCH'] = 'foo'