lazy-import-immediately-resolved (TID255)
Preview (since 0.15.13) · Related issues · View source
Derived from the flake8-tidy-imports linter.
Fix is sometimes available.
This rule is unstable and in preview. The --preview flag is required for use.
What it does
Checks for lazy imports that are resolved immediately at module load time.
Why is this bad?
Python 3.15 adds support for lazy import and lazy from ... import ...,
which defer the actual import work until the imported name is first used.
When a lazily imported name is used immediately at module load time, the import is resolved eagerly, defeating the purpose of marking the import as lazy. This is commonly caused by using a lazily imported module in a module global or in a top-level class definition.
The rule also recognizes imports made lazy by a literal __lazy_modules__
declaration, even when the target version is older than Python 3.15.
Such imports remain eager on older Python versions. Dynamic assignments
to __lazy_modules__ (e.g. __lazy_modules__ = non_literal()) are ignored,
as their effects cannot be determined statically.
Example
Use instead:
Fix availability
The fix is only available when the lazy import statement imports a single
member, since removing lazy from a multi-member import would make every
imported member eager, including names that may not be resolved immediately.
Fixes are unavailable for imports governed by a __lazy_modules__ declaration.
Fix safety
This rule's fix is marked as unsafe because converting a lazy import to an eager import changes when the imported module is executed, which can change runtime behavior if the module has import-time side effects.
Options
The rule ignores imports required to be lazy by the following setting: