Fix: Model.__init__ does a per-field import inside its hot per-instance loop - #123
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…ce loop Reproduced and fixed the finding. plain-postgres/plain/postgres/base.py's Model.__init__ had `from plain.postgres.fields.related import RelatedField` inside the `for field in meta.fields:` loop (line 122-123) — executed once per field per instance construction. Crucially, `RelatedField` is already imported at module level in the same file (line 30) and used by five other call sites in base.py (is_cached checks at lines 321/516, related-field filters at 884/1041/1195) — so the inline import was a pure redundant re-import with zero functional purpose (no circular-import need, nothing lazy/deferred about it). I benchmarked real Model construction (ContactSubmission with 4 fields, and Note with a ForeignKeyField/RelatedField) in the example app before and after removing the inline import, and per-instance time dropped by roughly 15-20% consistently across repeated runs, confirming the overhead was real and eliminated by hoisting nothing — the loop-local import statement was simply removed since the name was already bound at module scope. Fixed by deleting the two redundant lines from the loop body. Ran `./scripts/fix plain-postgres` (clean) and the full `./scripts/test plain-postgres` suite (795 passed, 1 skipped, unrelated) plus the example app test (1 passed) on the patched tree — no regressions. Note: this sandbox had no `uv`, Postgres, or psycopg-binary preinstalled; I installed `uv` via pip, installed PostgreSQL via apt (sudo available), and added `psycopg-binary` to make the example app runnable for benchmarking/testing — these are sandbox bootstrap steps only, not part of the committed fix.
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Reproduced and fixed the finding. plain-postgres/plain/postgres/base.py's Model.init had
from plain.postgres.fields.related import RelatedFieldinside thefor field in meta.fields:loop (line 122-123) — executed once per field per instance construction. Crucially,RelatedFieldis already imported at module level in the same file (line 30) and used by five other call sites in base.py (is_cached checks at lines 321/516, related-field filters at 884/1041/1195) — so the inline import was a pure redundant re-import with zero functional purpose (no circular-import need, nothing lazy/deferred about it). I benchmarked real Model construction (ContactSubmission with 4 fields, and Note with a ForeignKeyField/RelatedField) in the example app before and after removing the inline import, and per-instance time dropped by roughly 15-20% consistently across repeated runs, confirming the overhead was real and eliminated by hoisting nothing — the loop-local import statement was simply removed since the name was already bound at module scope. Fixed by deleting the two redundant lines from the loop body. Ran./scripts/fix plain-postgres(clean) and the full./scripts/test plain-postgressuite (795 passed, 1 skipped, unrelated) plus the example app test (1 passed) on the patched tree — no regressions. Note: this sandbox had nouv, Postgres, or psycopg-binary preinstalled; I installeduvvia pip, installed PostgreSQL via apt (sudo available), and addedpsycopg-binaryto make the example app runnable for benchmarking/testing — these are sandbox bootstrap steps only, not part of the committed fix.Opened by a PullApprove implementation run (implement-finding v4) for:
Merging this is what closes them as fixed.