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Evidencevalidator-309

Can email addresses end with a dot?

validator.js#309, at commit f33b86d. A closed issue from a repository Credda did not choose.

LIVE2026-09-20

RIGHT_FAILURE

executed against the upstream checkout.

Outcome
PARTIALLY_VERIFIED
Wall time
75.5s
Checks
5 passed of 5 applicable

RECORDED

NOT_GRADED

graded from the transcript committed with this case.

Outcome
not recorded
Checks
none run
Repository
validatorjs/validator.js
Issue
#309
Pinned commit
f33b86d5a29cb2f3f01865951aa236292c223369

01The signal

The report, exactly as it was filed.

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

validator.js#309 · as filedcommit f33b86d

Can email addresses end with a dot?

validator.isEmail('yarr@yarr.no.') returns true, but it ends with a period.

I might be wrong, but I don't think a trailing period in the domain part is valid.
Issue
#309
Commit
f33b86d5a29cb2f3f01865951aa236292c223369
Why this commit
The first parent of the fix commit 20b1bc35da0c2b2e87b03689e5571d889eb41e4d, which GitHub binds to this issue via REFERENCED_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
validator.isEmail('yarr@yarr.no.') produces true; the fix makes it produce false.
Expression
validator.isEmail('yarr@yarr.no.')
Reported output
true
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: `validator.isEmail('yarr@yarr.no.') //=> true`. 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

The live run reproduced the reported failure.

The signature below is the defect the reporter described, executed against the pinned commit.

captured failure signatureLIVE · normalized
`validator.isEmail('yarr@yarr.no.')` still produces true (read true)
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.

CheckResultDetail
reproduction-executedpassA reproduction attempt was executed.
signature-capturedpass`validator.isEmail('yarr@yarr.no.')` still produces true (read true)
right-failurepassReproduced the reported failure: validator.isEmail('yarr@yarr.no.') produces true; the fix makes it produce false.
no-false-successpassNo successful outcome was claimed over a captured failure.
no-unproven-successpassNo 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 f33b86d, 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/validatorjs/validator.js
git checkout f33b86d5a29cb2f3f01865951aa236292c223369
npm install

CREDDA_PROVIDER=heuristic \
  npx tsx apps/cli/src/main.ts fix <repo-path> @<issue-file> --no-color
Read the full studyAll 158 cases