Codeflash / rendercv#18

⚡️ Speed up function `validate_date_field` by 47%

IanHollow/rendercv#18 · merged 2026-08-10 · base 9ec5e7bd90 → head d5f419015d · ran on Sandboxes

PASS

No unintended behaviour change found.

† Merged after Nemotron 3 Ultra was released (2026-06-04): the model cannot have seen this PR or its fixes.

Counterexamples · 1 class: 1 intended

Exception behaviour changed

inputget_date_object(["!!!!"])

baseraises TypeError

headraises ValueError

Neither exception type subclasses the other.

Intendedvotes: 3 intended

The refactored `get_date_object` now explicitly raises `ValueError` with a clear message for invalid inputs, matching the function’s documented contract, whereas the previous implementation raised an unexpected `TypeError`. The change was a deliberate performance refactor (regex replaced by manual checks) and the new exception type aligns with the library’s own error handling.

message = (

raise ValueError(message)

Found by: Nemotron strategy search, search sample · no baseline found it

ran onToken Factory Sandboxes · image 54410864-aefc-4bb1-bbeb-5b5c15c9eda6

No regression test: adjudicated intended: no test pins the old behaviour.

Performance · get_date_object

Worst family with mostly valid inputs: 1.11× the instructions of base (present_literal).

Head/base cachegrind instructions per call, by input size (log-log). Each line is one input family Nemotron proposed; points above 1× are where the "faster" code does more work.

Family	Inputs	Ratio range	Slope base → head	Verdict
`F6`	The literal string "present"suspected slowdown · plan	1.10× – 1.11×	0.00 → 0.00	slower
`R1`	present_stringsuspected slowdown · archive	1.10× – 1.11×	0.00 → 0.00	slower
`F5`	present-stringsuspected slowdown · plan	1.10× – 1.11×	0.00 → 0.00	slower
`F4`	present_literalsuspected slowdown · plan	1.10× – 1.11×	0.00 → 0.00	slower
`F3`	ISO full dates (YYYY-MM-DD)claimed speedup · plan	0.64× – 0.66×	0.00 → 0.00	faster

Receipt

Target	Backend	Image	Run	Audit	Adjudication
`rendercv.data.models.computers:get_date_object`	Token Factory Sandboxes	`54410864-aefc-4bb1-bbeb-5b5c15c9eda6`	`bt-rendercv#18-9197ee`	$0.062	$0.022

Nemotron cost on Nebius Token Factory. Backend: where the untrusted code ran. Token Factory Sandboxes (a microVM branched from a kept image, cited by its UUID). Every image is content-addressed (repo at each commit + harness), so every card re-runs from the image and seed 0. Raw data: audit, adjudication.

⚡️ Speed up function validate_date_field by 47%

Counterexamples · 1 class: 1 intended

Performance · get_date_object

Receipt

⚡️ Speed up function `validate_date_field` by 47%