Add ruff to local tests and CI (#10116)

* Add ruff to local tests and CI

This adds linting using ruff to the relevant configuration files. Only
a few rules are enabled and none of them trigger an error in the current
state of the repo.

* Add comments on running black separately from tox

* Simplify and remove potentially bug causing instructions in CONTRIBUTING

* Update pyproject.toml

Co-authored-by: Eric Arellano <14852634+Eric-Arellano@users.noreply.github.com>

---------

Co-authored-by: Eric Arellano <14852634+Eric-Arellano@users.noreply.github.com>

.azure/lint-linux.yml

@@ -43,6 +43,8 @@ jobs:
       - bash: |
           set -e
           source test-job/bin/activate
+          echo "Running ruff"
+          ruff qiskit test tools examples setup.py
           echo "Running pylint"
           pylint -rn qiskit test tools
           echo "Running Cargo Clippy"

CONTRIBUTING.md

@@ -422,25 +422,34 @@ Note: If you have run `test/ipynb/mpl_tester.ipynb` locally it is possible some
 
 ## Style and lint
 
-Qiskit Terra uses 2 tools for verify code formatting and lint checking. The
+Qiskit Terra uses three tools for verify code formatting and lint checking. The
 first tool is [black](https://github.com/psf/black) which is a code formatting
 tool that will automatically update the code formatting to a consistent style.
 The second tool is [pylint](https://www.pylint.org/) which is a code linter
 which does a deeper analysis of the Python code to find both style issues and
-potential bugs and other common issues in Python.
+potential bugs and other common issues in Python. The third tool is the linter
+[ruff](https://github.com/charliermarsh/ruff), which has been recently
+introduced into Qiskit Terra on an experimental basis. Only a very small number
+of rules are enabled.
 
-You can check that your local modifications conform to the style rules
-by running `tox -elint` which will run `black` and `pylint` to check the local
-code formatting and lint. If black returns a code formatting error you can
-run `tox -eblack` to automatically update the code formatting to conform to
-the style. However, if `pylint` returns any error you will have to fix these
-issues by manually updating your code.
+You can check that your local modifications conform to the style rules by
+running `tox -elint` which will run `black`, `ruff`, and `pylint` to check the
+local code formatting and lint. If black returns a code formatting error you can
+run `tox -eblack` to automatically update the code formatting to conform to the
+style. However, if `ruff` or `pylint` return any error you will have to fix
+these issues by manually updating your code.
 
-Because `pylint` analysis can be slow, there is also a `tox -elint-incr` target, which only applies
-`pylint` to files which have changed from the source github. On rare occasions this will miss some
-issues that would have been caught by checking the complete source tree, but makes up for this by
-being much faster (and those rare oversights will still be caught by the CI after you open a pull
-request).
+Because `pylint` analysis can be slow, there is also a `tox -elint-incr` target,
+which runs `black` and `ruff` just as `tox -elint` does, but only applies
+`pylint` to files which have changed from the source github. On rare occasions
+this will miss some issues that would have been caught by checking the complete
+source tree, but makes up for this by being much faster (and those rare
+oversights will still be caught by the CI after you open a pull request).
+
+Because they are so fast, it is sometimes convenient to run the tools `black` and `ruff` separately
+rather than via `tox`. If you have installed the development packages in your python environment via
+`pip install -r requirements-dev.txt`, then `ruff` and `black` will be available and can be run from
+the command line. See [`tox.ini`](tox.ini) for how `tox` invokes them.
 
 ## Development Cycle
 

Makefile

@@ -12,9 +12,9 @@
 
 OS := $(shell uname -s)
 
-.PHONY: default env lint lint-incr style black test test_randomized pytest pytest_randomized test_ci coverage coverage_erase clean
+.PHONY: default ruff env lint lint-incr style black test test_randomized pytest pytest_randomized test_ci coverage coverage_erase clean
 
-default: style lint-incr test ;
+default: ruff style lint-incr test ;
 
 # Dependencies need to be installed on the Anaconda virtual environment.
 env:
@@ -41,6 +41,9 @@ lint-incr:
 	tools/verify_headers.py qiskit test tools examples
 	tools/find_optional_imports.py
 
+ruff:
+	ruff qiskit test tools examples setup.py
+
 style:
 	black --check qiskit test tools examples setup.py
 

pyproject.toml

@@ -23,6 +23,14 @@ environment = 'RUSTUP_TOOLCHAIN="stable"'
 before-all = "yum install -y wget && {package}/tools/install_rust.sh"
 environment = 'PATH="$PATH:$HOME/.cargo/bin" CARGO_NET_GIT_FETCH_WITH_CLI="true" RUSTUP_TOOLCHAIN="stable"'
 
+[tool.ruff]
+select = [
+  "F631",
+  "F632",
+  "F634",
+  "F823",
+]
+
 [tool.pylint.main]
 extension-pkg-allow-list = [
     "numpy",

requirements-dev.txt

@@ -11,6 +11,7 @@ black[jupyter]~=22.0
 pydot
 astroid==2.14.2
 pylint==2.16.2
+ruff==0.0.267
 stestr>=2.0.0,!=4.0.0
 pylatexenc>=1.4
 ddt>=1.2.0,!=1.4.0,!=1.4.3

tox.ini

@@ -24,6 +24,7 @@ commands =
 [testenv:lint]
 basepython = python3
 commands =
+  ruff check qiskit test tools examples setup.py
   black --check {posargs} qiskit test tools examples setup.py
   pylint -rn qiskit test tools
   # This line is commented out until #6649 merges. We can't run this currently
@@ -38,6 +39,7 @@ commands =
 basepython = python3
 allowlist_externals = git
 commands =
+  ruff check qiskit test tools examples setup.py
   black --check {posargs} qiskit test tools examples setup.py
   -git fetch -q https://github.com/Qiskit/qiskit-terra.git :lint_incr_latest
   python {toxinidir}/tools/pylint_incr.py -rn -j4 -sn --paths :/qiskit/*.py :/test/*.py :/tools/*.py