Some packages require being able to redefine the compiler variables
set to add additional base arguments that must be used everywhere.
This change makes it possible for that to work correctly.
The kernel doesn't do a complete build for all arches. And example is i686 in Fedora, where only kernel-headers is built.
kernel-srpm-macros provides %kernel_arches so that the various packages have a consistent way to check for this.
A new script brp-fix-pyc-reproducibility creates an opt-in way of how to fix
problems with the reproducibility of byte-compiled Python files. The script
uses marshalparser [0] which currently doesn't provide solutions for all issues
but can fix at least problems with reference flags. For more info see
this Bugzilla [1].
If you want to use this new feature, you need to define
`%py_reproducible_pyc_path` to specify a path you want to fix `.pyc`
files in (recursively) and build-require /usr/bin/marshalparser.
if you forget to build-require the parser. The error message is:
```
+ /usr/lib/rpm/redhat/brp-python-bytecompile '' 1 0
Bytecompiling .py files below /builddir/build/BUILDROOT/tldr-0.5-2.fc33.x86_64/usr/lib/python3.9 using /usr/bin/python3.9
+ /usr/lib/rpm/redhat/brp-fix-pyc-reproducibility /builddir/build/BUILDROOT/tldr-0.5-2.fc33.x86_64
ERROR: If %py_reproducible_pyc_path is defined, you have to also BuildRequire: /usr/bin/marshalparser !
error: Bad exit status from /var/tmp/rpm-tmp.UUJr4v (%install)
```
A build fails if the parser is not able to parse any of the `.pyc` files.
And finally, if a build is properly configured it produces fixed `.pyc` files.
Currently, `.pyc` files in the tldr package contain a lot of unused reference flags:
```
$ dnf install -y tldr
$ marshalparser --unused /usr/lib/python3.9/site-packages/__pycache__/tldr.cpython-39.pyc
… long output …
190 - Flag_ref(byte=9610, type='TYPE_SHORT_ASCII_INTERNED', content=b'init', usages=0)
191 - Flag_ref(byte=9633, type='TYPE_SHORT_ASCII_INTERNED', content=b'source', usages=0)
192 - Flag_ref(byte=9651, type='TYPE_SHORT_ASCII_INTERNED', content=b'argv', usages=0)
193 - Flag_ref(byte=9657, type='TYPE_SHORT_ASCII_INTERNED', content=b'print_help', usages=0)
194 - Flag_ref(byte=9669, type='TYPE_SHORT_ASCII_INTERNED', content=b'stderr', usages=0)
195 - Flag_ref(byte=9682, type='TYPE_SHORT_ASCII_INTERNED', content=b'parse_args', usages=0)
196 - Flag_ref(byte=9737, type='TYPE_SHORT_ASCII_INTERNED', content=b'encode', usages=0)
197 - Flag_ref(byte=9782, type='TYPE_SHORT_ASCII_INTERNED', content=b'parser', usages=0)
198 - Flag_ref(byte=9790, type='TYPE_SHORT_ASCII_INTERNED', content=b'options', usages=0)
199 - Flag_ref(byte=9799, type='TYPE_SHORT_ASCII_INTERNED', content=b'rest', usages=0)
200 - Flag_ref(byte=9821, type='TYPE_SHORT_ASCII_INTERNED', content=b'result', usages=0)
202 - Flag_ref(byte=10022, type='TYPE_SHORT_ASCII_INTERNED', content=b'__main__', usages=0)
203 - Flag_ref(byte=10102, type='TYPE_SHORT_ASCII_INTERNED', content=b'argparse', usages=0)
204 - Flag_ref(byte=10433, type='TYPE_SHORT_ASCII_INTERNED', content=b'__name__', usages=0)
205 - Flag_ref(byte=10463, type='TYPE_SHORT_ASCII_INTERNED', content=b'<module>', usages=0)
```
This new feature fixes them:
```
$ marshalparser --unused /usr/lib/python3.9/site-packages/__pycache__/tldr.cpython-39.pyc
<empty output>
```
[0] https://github.com/fedora-python/marshalparser
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1686078
This cuts the kernel provide generation time from ~33s to 2.5s on my laptop.
Tighten the path matching rule a bit while at it - it doesn't matter that
much with parametric generator but there's no point looking at entries
we don't generate dependencies on.
Resolves: rhbz#1595265
The problem this change is intended to solve is with how `real_libdir`
is calculated. Let's assume we want to recursively byte-compile all
`*.py` files in
`/builddir/build/BUILDROOT/python-scales-1.0.9-250.fc32.x86_64/usr/lib/python3.8`.
Then, `real_libdir` is this path without `$RPM_BUILD_ROOT` with
the filename at the end which displays in the error message like this:
```
Bytecompiling .py files below /builddir/build/BUILDROOT/python-scales-1.0.9-250.fc32.x86_64/usr/lib/python3.8 using /usr/bin/python3.8
*** Error compiling '/builddir/build/BUILDROOT/python-scales-1.0.9-250.fc32.x86_64/usr/lib/python3.8/site-packages/greplin/bar.py'...
File "/usr/lib/python3.8/bar.py", line 1
import sin from math
^
SyntaxError: invalid syntax
```
`/usr/lib/python3.8/bar.py` is obviously wrong.
One of the new features of the `compileall2` module (which will
be available in stdlib in Python 3.9) is that the path byte-compiled to
`*.pyc` files is calculated for each file. This means that by using
`-s` and `-p` we can strip `$RPM_BUILD_ROOT` and prepend `/` for each
file individually which will fix the problem.
```
Bytecompiling .py files below /builddir/build/BUILDROOT/python-scales-1.0.9-250.fc32.x86_64/usr/lib/python3.8 using /usr/bin/python3.8
*** Error compiling '/builddir/build/BUILDROOT/python-scales-1.0.9-250.fc32.x86_64/usr/lib/python3.8/site-packages/greplin/bar.py'...
File "/usr/lib/python3.8/site-packages/greplin/bar.py", line 1
import sin from math
^
SyntaxError: invalid syntax
```
This change has an effect only for Python >= 3.4.
