Evidencemathjs-3100

Bug on simple rounding

mathjs#3100, at commit 9baf478. A closed issue from a repository Credda did not choose.

LIVE2026-09-20

NO_FAILURE_OBSERVED

executed against the upstream checkout.

Outcome: NO_RUNNABLE_CHECK
Wall time: 92.7s
Checks: 3 passed of 5 applicable

RECORDED

NOT_GRADED

graded from the transcript committed with this case.

Outcome: not recorded
Checks: none run

Repository: josdejong/mathjs
Issue: #3100
Pinned commit: 9baf478f708755d82ea0c313c7264436ed2f3190

01The signal

The report, exactly as it was filed.

Nothing paraphrased or cleaned up. The mess is the thing under test.

mathjs#3100 · as filedcommit 9baf478

Bug on simple rounding

The issues section is used only for bug reports. Please use the [Discussions](https://github.com/josdejong/mathjs/discussions) section to ask questions and share ideas and suggestions.

**Describe the bug**
I use this library for simple rounding of currency values. Below, I want to convert 0.145 € to cents.

**To Reproduce**
round(0.145*100) returns 14, which should be actually 15
round(evaluate('0.145 * 100')) returns also 14, which is wrong
round(14.5) returns 15, which is correct

Repository: josdejong/mathjs
Issue: #3100
Commit: 9baf478f708755d82ea0c313c7264436ed2f3190
Why this commit: The first parent of the fix commit 85b65da6cb56fe2d62ce68bd189377dde05e9919, which GitHub binds to this issue via CLOSED_EVENT_COMMIT. Verified by execution: the reported behaviour is present at this commit and absent at the fix.
How the text was obtained: Fetched verbatim via the GitHub GraphQL API. Title on the first line, body unmodified below it. Nothing was paraphrased, cleaned up, or supplemented.
Toolchain: javascript · node · unknown · npm

02What counts as reproducing it

The bar, written down before the run.

expected.reportedFailurecommitted with the case

Symptom: round(0.145*100) produces 14; the fix makes it produce 15.
Expression: round(0.145*100)
Reported output: 14
Where that came from: Proposed by a model reading this report and nothing else -- it never saw the repository or the fix commit -- and read back as a claim by the same parser the harvest uses, SAME_LINE form: `round(0.145*100) //=> 14`. The report sat in the NO_FENCE_PROSE_ONLY bucket, which no regex reaches. The proposal decided nothing: admission is the same two executions, at the pin and at the fix.

03What happened

No failure was captured.

Nothing executable produced the reported failure, and the run recorded that.

bench external · checks · LIVE5 checks · 2026-09-20

The LIVE grading as emitted. A check that did not apply is never shown as a pass.

Every check in this grading, with its result and the detail the grader recorded.
Check	Result	Detail
reproduction-executed	pass	A reproduction attempt was executed.
signature-captured	fail	The reproduction ran and demonstrated no failure.
right-failure	fail	Expected `round(0.145*100)` still producing 14.
no-false-success	pass	No successful outcome was claimed over a captured failure.
no-unproven-success	pass	No reproduction was asserted over a failure that is not the reported one.

bench/external/scorecard.json, the run of 2026-09-20 against all 158 upstream checkouts.

The same case, graded from the transcript recorded .

The grading the benchmark gate runs on. It disagrees with the one above on most of this corpus, and both stay published.

Check it yourself

Everything here is downstream of a public commit.

Clone it, check out 9baf478, run the report through the CLI the way the study did.

How the study invoked itone isolated home per case

git clone https://github.com/josdejong/mathjs
git checkout 9baf478f708755d82ea0c313c7264436ed2f3190
npm install

CREDDA_PROVIDER=heuristic \
  npx tsx apps/cli/src/main.ts fix <repo-path> @<issue-file> --no-color

Read the full study All 158 cases