test: Create pylint rule for py_binary/library targets

.ci/micromamba/ci.yaml

@@ -8,7 +8,6 @@ channels:
 dependencies:
   - python=3.11
   - pytest
-  - pylint
   - pycodestyle
   - buildifier
   - clang=21

.ci/micromamba/env.yaml

@@ -8,7 +8,6 @@ channels:
 dependencies:
   - python=3.11
   - pytest
-  - pylint
   - pycodestyle
   - buildifier
   - clang=21

.github/workflows/test.yaml

@@ -80,8 +80,8 @@ jobs:
 
       - name: Run lint tests
         run: |
-          pylint .
           bazel test //test/buildifier --test_output=all
+          bazel test //... --test_tag_filters=pylint --test_output=all
         shell: bash -el {0}
 
       # Splitting test runs to: bazel unit tests, bazel foss tests, python unittests
@@ -155,8 +155,8 @@ jobs:
 
       - name: Run lint tests
         run: |
-          pylint .
           runuser -u test -- bazel test //test/buildifier --test_output=all
+          runuser -u test -- bazel test //... --test_tag_filters=pylint --test_output=all
         shell: bash -el {0}
 
       # Splitting test runs to: bazel unit tests, bazel foss tests, python unittests

MODULE.bazel

@@ -44,6 +44,28 @@ codechecker_extension = use_extension(
 )
 use_repo(codechecker_extension, "default_codechecker_tools")
 
+python = use_extension(
+    "@rules_python//python/extensions:python.bzl",
+    "python",
+    dev_dependency = True,
+)
+python.toolchain(
+    is_default = True,
+    python_version = "3.12",
+)
+
+pip = use_extension(
+    "@rules_python//python/extensions:pip.bzl",
+    "pip",
+    dev_dependency = True,
+)
+pip.parse(
+    hub_name = "pylint_deps",
+    python_version = "3.12",
+    requirements_lock = "//test/pylint:requirements.txt",
+)
+use_repo(pip, "pylint_deps")
+
 register_toolchains(
     "//:default_toolchain",
 )

docs/contributing.md

@@ -97,9 +97,23 @@ Or let one script do the whole round:
 On how to run or add a new test, see
 [test/README.md](https://github.com/Ericsson/rules_codechecker/blob/main/test/README.md).
 
-Note that `test/unit/external_repository` is in `.bazelignore`, it consumes
-these rules as an external module and therefore runs through `pytest` only.
-It is the test that catches breakage visible to our users but not to us.
+### Linting Python with Bazel
+
+Python targets are linted through a per-target Bazel macro.
+Add a `pylint(...)` target next to a top-level
+`py_binary`/`py_library`/`py_test`:
+
+```starlark
+load("//test/pylint:pylint_test.bzl", "pylint")
+
+pylint(
+    name = "pylint",
+    targets = [":my_py_binary"],
+)
+```
+
+It lints the targets and their dependencies (except pip packages)
+These targets run as part of `bazel test //...` (tagged `pylint`).
 
 
 ## Submitting a patch

src/BUILD

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 load("@rules_python//python:py_binary.bzl", "py_binary")
+load("//test/pylint:pylint_test.bzl", "pylint")
 
 # Tool filter compile_commands.json file
 py_binary(
@@ -32,6 +33,15 @@ py_binary(
     visibility = ["//visibility:public"],
 )
 
+pylint(
+    name = "pylint",
+    targets = [
+        ":codechecker_script",
+        ":compile_commands_filter",
+        ":per_file_script",
+    ],
+)
+
 # The following are flags and default values for clang_tidy_aspect
 filegroup(
     name = "clang_tidy_config_default",

test/foss/BUILD

@@ -25,8 +25,22 @@
 # To add a new project: add a foss_test() call below.
 # -----------------------------------------------------------------------
 
+load("@rules_python//python:py_library.bzl", "py_library")
+load("//test/pylint:pylint_test.bzl", "pylint")
 load(":foss_test.bzl", "foss_test")
 
+# Library wrapping the foss_test runner so it can be linted.
+py_library(
+    name = "foss_test_runner_lib",
+    srcs = ["foss_test_runner.py"],
+    tags = ["manual"],
+)
+
+pylint(
+    name = "pylint",
+    targets = [":foss_test_runner_lib"],
+)
+
 foss_test(
     name = "zlib",
     tests = [

test/pylint/.pylintrc

@@ -0,0 +1,8 @@
+[MASTER]
+
+[FORMAT]
+max-line-length=80
+
+[MESSAGES CONTROL]
+disable=
+    fixme,

test/foss/__init__.py → test/pylint/BUILD

@@ -1,4 +1,4 @@
-# Copyright 2023 Ericsson AB
+# Copyright 2026 Ericsson AB
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,3 +11,26 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+load("@rules_python//python:py_binary.bzl", "py_binary")
+load("//test/pylint:pylint_test.bzl", "pylint")
+
+exports_files([
+    ".pylintrc",
+    "pylint_runner.py",
+    "requirements.txt",
+])
+
+py_binary(
+    name = "pylint_runner",
+    srcs = ["pylint_runner.py"],
+    main = "pylint_runner.py",
+    visibility = ["//visibility:public"],
+    deps = ["@pylint_deps//pylint"],
+)
+
+# Lint the pylint runner itself.
+pylint(
+    name = "pylint",
+    targets = [":pylint_runner"],
+)

test/pylint/pylint_runner.py

@@ -0,0 +1,79 @@
+# Copyright 2026 Ericsson AB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Runner script for the per-target pylint Bazel test.
+
+Reads a manifest of .py files (produced by the pylint rule) and runs
+pylint on exactly those files. Imports are resolved from this runner's
+own sys.path, which rules_python populates from the linted target's
+runfiles; no repository-root chdir is needed.
+
+Pylint is imported as a Python dependency provided by Bazel,
+not invoked from PATH.
+"""
+
+import argparse
+import os
+import sys
+
+from pylint import lint
+
+
+def read_manifest(manifest):
+    """Read the list of files to lint from the manifest."""
+    files = []
+    with open(manifest, encoding="utf-8") as handle:
+        for line in handle:
+            entry = line.strip()
+            if entry:
+                files.append(entry)
+    return files
+
+
+def main():
+    """Parse arguments and run pylint on the manifest sources."""
+    parser = argparse.ArgumentParser(
+        description="Run pylint on Python source files."
+    )
+    parser.add_argument(
+        "--manifest",
+        required=True,
+        help="Path to a manifest file listing the .py files to lint.",
+    )
+    parser.add_argument(
+        "--rcfile",
+        default=None,
+        help="Path to a .pylintrc configuration file.",
+    )
+    args = parser.parse_args()
+
+    rcfile_path = os.path.realpath(args.rcfile) if args.rcfile else None
+    sources = [os.path.realpath(s) for s in read_manifest(args.manifest)]
+
+    if not sources:
+        print("pylint_runner: no .py files found")
+        sys.exit(1)
+
+    pylint_args = []
+    if rcfile_path:
+        pylint_args.append(f"--rcfile={rcfile_path}")
+    pylint_args.extend(sources)
+
+    print(f"Running: pylint {' '.join(pylint_args)}")
+    result = lint.Run(pylint_args, exit=False)
+    sys.exit(result.linter.msg_status)
+
+
+if __name__ == "__main__":
+    main()