Contributor Guide

Synapse is a Python application that has Rust modules via pyo3 for performance.

Dev Environment Tips

Source code is primarily in synapse/, tests are in tests/.
Run poetry install --dev to install development python dependencies. This will also build and install the Synapse rust code.
Use ./scripts-dev/lint.sh to lint the codebase (this attempts to fix issues as well). This should be run and produce no errors before every commit.

If any change creates a breaking change or requires downstream users (sysadmins) to update their environment, call it out in docs/upgrade.md as a new entry with the title "# Upgrading to vx.yy.z" with the details of what they should do or be aware of.

Find the CI plan in the .github/workflows folder.
Use poetry run trial tests to run all unit tests, or poetry run trial tests.metrics.test_phone_home_stats.PhoneHomeStatsTestCase (for example) to run a single test case. The commit should pass all tests before you merge.
Some typing warnings are expected currently. Fix any test or type errors until the whole suite is green.
Add or update relevant tests for the code you change, even if nobody asked.