| # Supported Python Versions |
| |
| With Python 2.7 officially going EOL on [01 Jan 2020](https://pythonclock.org/), |
| we need a support plan for the repo project itself. |
| Inevitably, there will be a long tail of users who still want to use Python 2 on |
| their old LTS/corp systems and have little power to change the system. |
| |
| ## Summary |
| |
| * Python 3.6 (released Dec 2016) is required by default starting with repo-2.x. |
| * Older versions of Python (e.g. v2.7) may use the legacy feature-frozen branch |
| based on repo-1.x. |
| |
| ## Overview |
| |
| We provide a branch for Python 2 users that is feature-frozen. |
| Bugfixes may be added on a best-effort basis or from the community, but largely |
| no new features will be added, nor is support guaranteed. |
| |
| Users can select this during `repo init` time via the [repo launcher]. |
| Otherwise the default branches (e.g. stable & master) will be used which will |
| require Python 3. |
| |
| This means the [repo launcher] needs to support both Python 2 & Python 3, but |
| since it doesn't import any other repo code, this shouldn't be too problematic. |
| |
| The master branch will require Python 3.6 at a minimum. |
| If the system has an older version of Python 3, then users will have to select |
| the legacy Python 2 branch instead. |
| |
| ### repo hooks |
| |
| Projects that use [repo hooks] run on independent schedules. |
| They might migrate to Python 3 earlier or later than us. |
| To support them, we'll probe the shebang of the hook script and if we find an |
| interpreter in there that indicates a different version than repo is currently |
| running under, we'll attempt to reexec ourselves under that. |
| |
| For example, a hook with a header like `#!/usr/bin/python2` will have repo |
| execute `/usr/bin/python2` to execute the hook code specifically if repo is |
| currently running Python 3. |
| |
| For more details, consult the [repo hooks] documentation. |
| |
| |
| [repo hooks]: ./repo-hooks.md |
| [repo launcher]: ../repo |
