Add ruff unused import check to pre-commit and CI

.circleci/config.yml

@@ -28,10 +28,12 @@ jobs:
           name: Set Environment File
           command: cp local.env .env
 
+      - run: pipenv install pre-commit
+
       # Download and cache dependencies
       # ensure this step occurs *before* installing dependencies
       - restore_cache:
-          key: dependencies-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
+          key: dependencies-{{ .Branch }}-{{ checksum "Pipfile.lock" }}-{{ checksum ".pre-commit-config.yaml" }}
 
       - run:
           name: Install Dependencies
@@ -43,10 +45,16 @@ jobs:
             curl -Os https://uploader.codecov.io/latest/linux/codecov
             chmod +x codecov
 
+      - run:
+          name: Ruff
+          command: pipenv run pre-commit run ruff --from-ref origin/HEAD --to-ref HEAD
+
       - save_cache:
           paths:
-            - ./venv
-          key: dependencies-{{ .Branch }}-{{ checksum "Pipfile.lock" }}
+            - ./.venv
+            - ~/.cache/pre-commit
+          # the cache key changes whenever any of the branch name, Pipfile.lock checksum, or .pre-commit-config.yaml checksum change
+          key: dependencies-{{ .Branch }}-{{ checksum "Pipfile.lock" }}-{{ checksum ".pre-commit-config.yaml" }}
 
       - run:
           name: Check migrations are made
@@ -60,7 +68,7 @@ jobs:
       - run:
           name: Upload code coverage
           command: ./codecov
-  
+
   tests_postgres13:
     docker:
       - image: cimg/python:3.8.17

.pre-commit-config.yaml

@@ -1,5 +1,12 @@
 exclude: (exporter/assets/built/|caseworker/assets/built/)
 repos:
+  # ruff-pre-commit docs recommend running ruff before black
+    - repo: https://github.com/astral-sh/ruff-pre-commit
+      rev: v0.1.4
+      hooks:
+        # Config for ruff lives in pyproject.toml
+        - id: ruff
+          args: [ --fix ]
     - repo: https://github.com/psf/black
       rev: 22.3.0
       hooks:

pyproject.toml

@@ -5,7 +5,7 @@
 
 [tool.black]
 line-length = 120
-target-version = ['py36', 'py37', 'py38']
+target-version = ['py38']
 include = '\.pyi?$'
 exclude = '''
 /(
@@ -27,3 +27,6 @@ exclude = '''
 [tool.isort]
 profile = 'black'
 line_length = 120  # To match Black's line-length above.
+
+[tool.ruff.lint]
+select = ["F401"]