pycodestyle: Check *.in Python files

Many of IPA Python scripts are shebang configurable scripts and
have special suffix '.in' for that. Pycodestyle by default check
only '*.py' files [0].

[0]: https://pycodestyle.pycqa.org/en/latest/intro.html

Fixes: https://pagure.io/freeipa/issue/8961
Signed-off-by: Stanislav Levin <slev@altlinux.org>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: François Cami <fcami@redhat.com>

Makefile.am

@@ -230,6 +230,8 @@ fasttest: $(GENERATED_PYTHON_FILES) ipasetup.py
 	    --ignore $(abspath $(top_srcdir))/ipatests/test_xmlrpc
 
 fastcodestyle: $(GENERATED_PYTHON_FILES) ipasetup.py
+	@ # keep Python files in sync to pycodestyle configuration in
+	@ # tox.ini(filename=)
 	@echo "Fast code style checking with $(PYTHON) from branch '$(GIT_BRANCH)'"
 
 	@MERGEBASE=$$(git merge-base --fork-point $(GIT_BRANCH)); \
@@ -250,8 +252,8 @@ fastcodestyle: $(GENERATED_PYTHON_FILES) ipasetup.py
 	    echo -e "Fast code style checking for files:\n$${FILES}\n"; \
 	    echo "pycodestyle"; \
 	    echo "-----------"; \
-	    git diff -U0 $${MERGEBASE} | \
-	        $(PYTHON) -m pycodestyle --diff || exit $$?; \
+	    git diff -U0 $${MERGEBASE} -- $${FILES} | \
+	        $(PYTHON) -m pycodestyle -v --diff || exit $$?; \
 	else \
 	    echo "No modified Python files found"; \
 	fi

tox.ini

@@ -59,6 +59,7 @@ ignore = E203, E402, E231, W503, E731, E741
 max-line-length = 80
 # exclude auto-generated remote plugins
 exclude=.git,.venv,build,_build,rpmbuild,2_49,2_114,2_156,2_164
+filename=*.py,*.in
 
 [pytest]
 addopts = -ra -v