Add pre-commit config and GitHub Actions job (#1688)

* Add pre-commit config and GitHub Actions job

Contains the following hooks:
* buildifier - for formatting and linting Bazel files.
* mypy, ruff, isort, black - for Python typechecking, import hygiene,
static analysis, and formatting.

The pylint CI job was changed to be a pre-commit CI job, where pre-commit
is bootstrapped via Python.

Pylint is currently no longer part of the
code checks, but can be re-added if requested. The reason to drop was
that it does not play nicely with pre-commit, and lots of its
functionality and responsibilities are actually covered in ruff.

* Add dev extra to pyproject.toml for development installs

* Clarify that pre-commit contains only Python and Bazel hooks

* Add one-line docstrings to Bazel modules

* Apply buildifier pre-commit fixes to Bazel files

* Apply pre-commit fixes to Python files

* Supply --profile=black to isort to prevent conflicts

* Fix nanobind build file formatting

* Add tooling configs to `pyproject.toml`

In particular, set line length 80 for all Python files.

* Reformat all Python files to line length 80, fix return type annotations

Also ignores the `tools/compare.py` and `tools/gbench/report.py` files
for mypy, since they emit a barrage of errors which we can deal with
later. The errors are mostly related to dynamic classmethod definition.

1 files changed, 4 insertions, 1 deletions

diff --git a/bindings/python/google_benchmark/example.py b/bindings/python/google_benchmark/example.py
index d95a043..b5b2f88 100644
--- a/bindings/python/google_benchmark/example.py
+++ b/bindings/python/google_benchmark/example.py
@@ -38,6 +38,7 @@ def sum_million(state):
     while state:
         sum(range(1_000_000))
 
+
 @benchmark.register
 def pause_timing(state):
     """Pause timing every iteration."""
@@ -85,7 +86,9 @@ def custom_counters(state):
     # Set a counter as a rate.
     state.counters["foo_rate"] = Counter(num_foo, Counter.kIsRate)
     #  Set a counter as an inverse of rate.
-    state.counters["foo_inv_rate"] = Counter(num_foo, Counter.kIsRate | Counter.kInvert)
+    state.counters["foo_inv_rate"] = Counter(
+        num_foo, Counter.kIsRate | Counter.kInvert
+    )
     # Set a counter as a thread-average quantity.
     state.counters["foo_avg"] = Counter(num_foo, Counter.kAvgThreads)
     # There's also a combined flag: