%exclude (as used in the %files section of spec files) is not documented

[fweimer-rh]

In glibc.spec, we have considerable scripting logic to distribute files among subpackages, see split_sysroot_file_list. It's way less involved than it used to be, but with the right %exclude semantics, we could make this much clearer.

I see that #994 criticizes the current behavior. And indeed it would be more general if some sequence of directives could add files matching a few patterns to one subpackage file list, then remove some files matching different patterns, and then add back a few exceptions that were removed before. With the current unordered %exclude, that is not possible. And without documentation, we don't really know if the current behavior is deemed permanent.

[dmnks]

The present %exclude semantics isn't ideal, indeed, and there are plans to change that in the future (#994) so documenting the status quo probably wouldn't make much sense and would make changes to it more complicated and/or risky.

Either way, could you please give a concrete (simplified) example of what semantics you'd like it to have? A random trivial example that comes to mind is (based on your description):

[...]

%install
mkdir -p $RPM_BUILD_ROOT/usr/bin
touch $RPM_BUILD_ROOT/usr/bin/foo{1,2,3}

%files
/usr/bin
%exclude /usr/bin/foo{2,3}

%files foobar
/usr/bin/foo2

But that already works as expected (i.e. main package owning foo1 and foobar subpackage owning foo2).