ci: add .flake8 linting to ci scripts and tests

Currently the ci scripts and tests don't have any linting checks. Add
.flake8 linting to start adding some consistency to the scripts. Ignore
most of the existing errors until they can be addressed on an individual
basis.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32602>

.gitlab-ci/.flake8

@@ -0,0 +1,33 @@
+[flake8]
+exclude = .venv*,
+
+# PEP 8 Style Guide limits line length to 79 characters
+max-line-length = 167
+
+ignore =
+    # continuation line under-indented for hanging indent
+    E121
+    # continuation line over-indented for hanging indent
+    E126,
+    # continuation line under-indented for visual indent
+    E128,
+    # whitespace before ':'
+    E203,
+    # missing whitespace around arithmetic operator
+    E226,
+    # missing whitespace after ','
+    E231,
+     # expected 2 blank lines, found 1
+    E302,
+    # too many blank lines
+    E303,
+    # imported but unused
+    F401,
+    # f-string is missing placeholders
+    F541,
+    # local variable assigned to but never used
+    F841,
+    # line break before binary operator
+    W503,
+    #  line break after binary operator
+    W504,

.gitlab-ci/run-pytest.sh

@@ -54,3 +54,9 @@ PYTHONPATH="${LIB_TEST_DIR}:${SCRIPT_TEST_DIR}:${PYTHONPATH:-}" python3 -m \
 	    ${PYTEST_VERBOSE:-}
 
 section_end pytest
+
+section_start flake8 "flake8"
+flake8 \
+--config "${CI_PROJECT_DIR}/.gitlab-ci/.flake8" \
+"${LIB_TEST_DIR}" "${SCRIPT_TEST_DIR}"
+section_end flake8

bin/ci/requirements.txt

@@ -1,8 +1,12 @@
+# If you change these requirements, and you need these packages
+# to be available in the debian/x86_64_pyutils container
+# then bump the DEBIAN_PYUTILS_TAG
 PyYAML==6.*
 colorama==0.4.*
 filecache==0.81
 filelock==3.*
 fire==0.5.0
+flake8==7.*
 gql==3.*
 kaleido==0.2.*
 lavacli==1.5.2