add pre-commit hooks for convenient formatting checks

.circleci/config.yml.in

@@ -192,8 +192,9 @@ jobs:
       - checkout
       - run:
           command: |
-            pip install --user --progress-bar off flake8 typing
-            flake8 --config=setup.cfg .
+            pip install --user --progress-bar off pre-commit
+            pre-commit install-hooks
+      - run: pre-commit run --all-files
 
   python_type_check:
     docker:

.circleci/unittest/linux/scripts/run-clang-format.py

@@ -21,8 +21,8 @@
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
-"""
-"""A wrapper script around clang-format, suitable for linting multiple files
+
+A wrapper script around clang-format, suitable for linting multiple files
 and to use for continuous integration.
 
 This is an alternative API for the clang-format command line.

.circleci/unittest/windows/scripts/install_conda.bat

@@ -1 +1 @@
-start /wait "" "%miniconda_exe%" /S /InstallationType=JustMe /RegisterPython=0 /AddToPath=0 /D=%tmp_conda%
+start /wait "" "%miniconda_exe%" /S /InstallationType=JustMe /RegisterPython=0 /AddToPath=0 /D=%tmp_conda%

.pre-commit-config.yaml

@@ -0,0 +1,14 @@
+repos:
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: 3.9.2
+    hooks:
+      - id: flake8
+        args: [--config=setup.cfg]
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.0.1
+    hooks:
+      - id: check-docstring-first
+      - id: check-toml
+      - id: check-yaml
+        exclude: packaging/.*
+      - id: end-of-file-fixer

CONTRIBUTING.md

@@ -64,7 +64,7 @@ If you plan to modify the code or documentation, please follow the steps below:
 2. If you have modified the code (new feature or bug-fix), please add unit tests.
 3. If you have changed APIs, update the documentation. Make sure the documentation builds.
 4. Ensure the test suite passes.
-5. Make sure your code passes `flake8` formatting check.
+5. Make sure your code passes the formatting checks (see below).
 
 For more details about pull requests, 
 please read [GitHub's guides](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request). 
@@ -75,9 +75,19 @@ If you would like to contribute a new dataset, please see [here](#New-dataset).
 
 ### Code formatting and typing
 
-New code should be compatible with Python 3.X versions and be compliant with PEP8. To check the codebase, please run
+Contributions should be compatible with Python 3.X versions and be compliant with PEP8. To check the codebase, please 
+either run
 ```bash
-flake8 --config=setup.cfg .
+pre-commit run --all-files
+```
+or run
+```bash
+pre-commit install
+```
+once to perform these checks automatically before every `git commit`. If `pre-commit` is not available you can install 
+it with
+```
+pip install pre-commit
 ```
 
 The codebase has type annotations, please make sure to add type hints if required. We use `mypy` tool for type checking:

android/build.gradle

@@ -39,4 +39,3 @@ allprojects {
 ext.deps = [
         jsr305: 'com.google.code.findbugs:jsr305:3.0.1',
 ]
-

android/test_app/app/src/main/res/layout/activity_main.xml

@@ -14,4 +14,4 @@
         android:background="@android:color/black"
         android:textColor="@android:color/white" />
 
-</FrameLayout>
+</FrameLayout>

docs/source/_static/css/custom_torchvision.css

@@ -9,4 +9,4 @@ torchvision it just hides the links. So we have to put them back here */
 article.pytorch-article .sphx-glr-download-link-note.admonition.note,
 article.pytorch-article .reference.download.internal, article.pytorch-article .sphx-glr-signature {
   display: block;
-}
+}

docs/source/feature_extraction.rst

@@ -126,4 +126,4 @@ API Reference
 
 .. autofunction:: create_feature_extractor
 
-.. autofunction:: get_graph_node_names
+.. autofunction:: get_graph_node_names

examples/cpp/hello_world/README.rst

@@ -16,4 +16,4 @@ Once both dependencies are sorted, we can start the CMake fun:
 
 | That's it!
 | You should now have a ``hello-world`` executable in your ``build`` folder.
- Running it will output a (fairly long) tensor of random values to your terminal.
+ Running it will output a (fairly long) tensor of random values to your terminal.

examples/python/README.md

@@ -1,4 +1,4 @@
 # Python examples
 
 The examples in this directory have been moved online in our [gallery
-page](https://pytorch.org/vision/stable/auto_examples/index.html).
+page](https://pytorch.org/vision/stable/auto_examples/index.html).

gallery/README.rst

@@ -1,4 +1,4 @@
 Example gallery
 ===============
 
-Below is a gallery of examples
+Below is a gallery of examples

ios/VisionTestApp/VisionTestApp/ViewController.h

@@ -5,4 +5,3 @@
 
 
 @end
-

packaging/vs2017/install_activate.bat

@@ -27,4 +27,3 @@ IF "%cross_compiler_target_platform%" == "win-64" (
   echo CALL "VC\Auxiliary\Build\vcvars32.bat" >> "%PREFIX%\etc\conda\activate.d\vs%YEAR%_compiler_vars.bat"
   echo popd
   )
-

packaging/vs2019/install_activate.bat

@@ -27,4 +27,3 @@ IF "%cross_compiler_target_platform%" == "win-64" (
   echo CALL "VC\Auxiliary\Build\vcvars32.bat" >> "%PREFIX%\etc\conda\activate.d\vs%YEAR%_compiler_vars.bat"
   echo popd
   )
-

references/classification/README.md

@@ -151,4 +151,3 @@ For post training quant, device is set to CPU. For training, the device is set t
 ```
 python train_quantization.py --device='cpu' --test-only --backend='<backend>' --model='<model_name>'
 ```
-

references/detection/README.md

@@ -79,4 +79,3 @@ python -m torch.distributed.launch --nproc_per_node=8 --use_env train.py\
     --dataset coco_kp --model keypointrcnn_resnet50_fpn --epochs 46\
     --lr-steps 36 43 --aspect-ratio-group-factor 3
 ```
-

test/test_video_reader.py

@@ -112,8 +112,8 @@
     "DecoderResult", "vframes vframe_pts vtimebase aframes aframe_pts atimebase"
 )
 
-"""av_seek_frame is imprecise so seek to a timestamp earlier by a margin
-The unit of margin is second"""
+# av_seek_frame is imprecise so seek to a timestamp earlier by a margin
+# The unit of margin is second
 seek_frame_margin = 0.25