Ruff includes an opt-in preview mode to provide an opportunity for community feedback and increase confidence that changes are a net-benefit before enabling them for everyone.
Preview mode enables a collection of newer lint rules, fixes, and formatter style changes that are considered experimental or unstable,.
Enabling preview mode#
Preview mode can be enabled with the
--preview flag on the CLI or by setting
preview = true in your Ruff
Preview mode can be configured separately for linting and formatting (requires Ruff v0.1.1+). To enable preview lint rules without preview style formatting:
To enable preview style formatting without enabling any preview lint rules:
Using rules that are in preview#
If a rule is marked as preview, it can only be selected if preview mode is enabled. For example, consider a
HYP001 were in preview, it would not be enabled by adding following to your
It also would not be enabled by selecting the
HYP category, like so:
Similarly, it would not be enabled via the
However, it would be enabled in any of the above cases if you enabled preview in your configuration file:
Or, if you provided the
--preview CLI flag.
To see which rules are currently in preview, visit the rules reference.
Selecting single preview rules#
When preview mode is enabled, selecting rule categories or prefixes will include all preview rules that match.
If you'd prefer to opt-in to each preview rule individually, you can toggle the
setting in your configuration file:
In our previous example,
HYP00 would not enable
HYP001. Each preview
rule will need to be selected with its exact code, e.g.
If preview mode is not enabled, this setting has no effect.
When preview mode is enabled, deprecated rules will be disabled. If a deprecated rule is selected explicitly, an error will be raised. Deprecated rules will not be included if selected via a rule category or prefix.