QUERY · ISSUE

MICROPY_PY_BUILTINS_ROUND_INT==0 breaks round(<int>, <n>)

openby dhalbertopened 2019-05-16updated 2019-08-20

Before https://github.com/micropython/micropython/commit/b318ebf1015ced6354f8bbaf035308214b3f5c5d, which was a rework of #3557, round(<int>, <n>) worked. Now, if MICROPY_PY_BUILTINS_ROUND_INT is set to 0, round(2, 2) or similar throws NotImplementedError. round(2) still works.

@dpgeorge Was it your intention to disable rounding of integers in this way completely, instead of just not handling negative values for the second arg if it was an int?

A user discovered this after ending up with an integer zero while doing some floating arithmetic.

CANDIDATE · PULL REQUEST

py: implemented rounding floats to precision

closedby turbinenreiteropened 2015-07-14updated 2015-07-19

in continuation of https://github.com/micropython/micropython/pull/1376

supports rounding floats to precision
uses macros
added warning may cause overflow

Assessment

S Sonnet · high

Both items involve the round() builtin's second argument in py/modbuiltins.c, but they address different problems. PR #1382 implements float precision rounding (adding support for round(float, N)) and predates the regression described in issue #4792. The issue reports that a later commit (b318ebf, from PR #3557) broke round(int, N) when MICROPY_PY_BUILTINS_ROUND_INT==0, causing NotImplementedError. PR #1382 does not address the MICROPY_PY_BUILTINS_ROUND_INT compile-time flag interaction with integer arguments at all — it is strictly about float rounding precision. The PR neither causes nor fixes the regression in the issue.

Suggested action

No action needed — PR #1382 is historical context only. The issue #4792 requires a separate fix targeting the MICROPY_PY_BUILTINS_ROUND_INT==0 code path for integer arguments with a second argument.

MICROPY_PY_BUILTINS_ROUND_INT==0 breaks round(<int>, <n>)

py: implemented rounding floats to precision

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