Anyone interested in testing this?

Your commit seems to have added an empty sup-0.22.1.gem file which is not wanted.

Apart from that, I built this for my F26 box and it works fine.

On startup it prints this:

Ignoring sup-0.22.1 because its extensions are not built.  Try: gem pristine sup --version 0.22.1

although it does work fine in spite of that error. Most likely it is because of some marker file which you are now excluding from the %files list, I remember a similar thing with gem.build_complete in rubygem-unicode a while back.

There are also some warnings about Fixnum deprecation:

/usr/share/gems/gems/sup-0.22.1/lib/sup/util.rb:474: warning: constant ::Fixnum is deprecated

I had fixed them in my local version of sup, I've filed a PR just now: https://github.com/sup-heliotrope/sup/pull/544 although upstream is long dead. These warnings are not fatal yet anyway.

If I touch /usr/lib64/gems/ruby/sup-0.22.1/gem.build_complete it makes the message about "Ignoring sup-0.22.1 because its extensions are not built" go away. But it doesn't make much sense. I can see that the gem build process does not itself create this file, because it's a pure Ruby gem, there are no compiled bits. So it (correctly) installs to /usr/share/gems and not /usr/lib64/gems.

I don't know why Ruby thinks sup should have a compiled extension...

Okay, it seems to be because of the weird ext/mkrf_conf_xapian.rb thing which is itself a bit of a hack. I don't think we need that in the Fedora package since we can just require the xapian ruby bindings as a normal package instead.

I see there is already mkrf_conf.patch being applied here but that is just flipping the conditional in the fake extension. It seems to have been written with a misunderstanding of what the extension is for. Better to just get rid of entirely I think, like this:

diff --git a/mkrf_conf.patch b/mkrf_conf.patch
deleted file mode 100644
index 86d9cc3..0000000
diff --git a/rubygem-sup.spec b/rubygem-sup.spec
index 43b4a65..eccc921 100644
--- a/rubygem-sup.spec
+++ b/rubygem-sup.spec
@@ -7,7 +7,6 @@ Release: 1%{?dist}
 License: GPLv2+
 URL: http://sup.rubyforge.org/
 Source0: http://rubygems.org/downloads/%{gem_name}-%{version}.gem
-Patch0: mkrf_conf.patch
 # Revert dependency on ncursesw. The downside is incorrect wide character support.
 # TODO: Resurrect rubygem-ncursesw (rhbz#597709).
 # https://github.com/sup-heliotrope/sup/commit/c52016368e0456baf1ee97d25304b703da542cec
@@ -57,9 +56,11 @@ is to become the email client of choice for nerds everywhere.
 gem unpack %{SOURCE0}
 %setup -q -D -T -n  %{gem_name}-%{version}
 gem spec %{SOURCE0} -l --ruby > %{gem_name}.gemspec
-%patch0 -p1
 %patch1 -p1

+# Remove unnecessary fake extension module
+sed -i '/s.extensions =/d' %{gem_name}.gemspec
+
 # Relax rubygem-chronic dependency.
 sed -i '/chronic/ s/0.9.1/0.9/' %{gem_name}.gemspec

This silences the complaint about the extension not being built.

Thanks for testing this!
I'll make the changes as suggested. Yes, as those Fixnum deprecations are just warnings, so let's hope the PR'll be merged (I won't apply a patch for that).

This PR is still adding an empty sup-0.22.1.gem file in git, what's up with that?

Apart from that, seems fine to me.

Yes, sorry I forgot to comment on that.

When one does merge this PR, then the sources file is already included it's possible to build the package without adding another commit (you just have to upload the file with the same checksum).

I've simply generated the file (manually, without uploading the .gem). This avoids irreversibly uploading the file into dist-git in case the PR wouldn't be merged (or f.e. new version would be released).

Thanks for review!

Correction: I've removed the empty .gem file.