PyAnnotate: Auto-generate PEP-484 annotations
Insert annotations into your source code based on call arguments and return types observed at runtime.
For license and copyright see the end of this file.
How to use
See also the example directory.
Phase 1: Collecting types at runtime
- Install the usual way (see "red tape" section below)
from pyannotate_runtime import collect_typesto your test
- Early in your test setup, call
- Bracket your test execution between calls to
collect_types.stop()(or use the context manager below)
- When done, call
All calls between the
stop() calls will be analyzed
and the observed types will be written (in JSON form) to the filename
you pass to
dump_stats(). You can have multiple start/stop pairs
per dump call.
If you'd like to automatically collect types when you run
Instead of using
stop() you can also use a context
collect_types.init_types_collection() with collect_types.collect(): <your code here> collect_types.dump_stats(<filename>)
Phase 2: Inserting types into your source code
The command-line tool
pyannotate can add annotations into your
source code based on the annotations collected in phase 1. The key
--type-info FILEto tell it the file you passed to
- Positional arguments are source files you want to annotate
- With no other flags the tool will print a diff indicating what it proposes to do but won't do anything. Review the output.
-wto make the tool actually update your files. (Use git or some other way to keep a backup.)
At this point you should probably run mypy and iterate. You probably will have to tweak the changes to make mypy completely happy.
Notes and tips
- It's best to do one file at a time, at least until you're comfortable with the tool.
- The tool doesn't touch functions that already have an annotation.
- The tool can generate either of:
- type comments, i.e. Python 2 style annotations
- inline type annotations, i.e. Python 3 style annotations, using
This should work for Python 2.7 as well as for Python 3.4 and higher.
pip install pyannotate
This installs several items:
A runtime module, pyannotate_runtime/collect_types.py, which collects and dumps types observed at runtime using a profiling hook.
A library package, pyannotate_tools, containing code that can read the data dumped by the runtime module and insert annotations into your source code.
An entry point, pyannotate, which runs the library package on your files.
For dependencies, see setup.py and requirements.txt.
To run the unit tests, use pytest:
We'd love your help with some of these issues:
- Better documentation.
- Python 3 code generation.
- Refactor the tool modules (currently its legacy architecture shines through).
The following people contributed significantly to this tool:
- Tony Grue
- Sergei Vorobev
- Jukka Lehtosalo
- Guido van Rossum
- License: Apache 2.0.
- Copyright attribution: Copyright (c) 2017 Dropbox, Inc.
- External contributions to the project should be subject to Dropbox's Contributor License Agreement (CLA): https://opensource.dropbox.com/cla/