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Evidencepath-to-regexp-148

An empty path does not match relative paths

path-to-regexp#148, at commit 761c721. A closed issue from a repository Credda did not choose.

LIVE2026-09-20

RIGHT_FAILURE

executed against the upstream checkout.

Outcome
PATCH_REJECTED
Wall time
122.4s
Checks
5 passed of 5 applicable

RECORDED

NOT_GRADED

graded from the transcript committed with this case.

Outcome
not recorded
Checks
none run
Repository
pillarjs/path-to-regexp
Issue
#148
Pinned commit
761c721f9516d2739f87af3d303f5c096d1159d9

01The signal

The report, exactly as it was filed.

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

path-to-regexp#148 · as filedcommit 761c721

An empty path does not match relative paths

When creating a regexp for an empty path in the prefix-matching mode (i.e. `end = false`) I want it to match _any_ path (because any string contains an empty string as a prefix). With path-to-regexp version 2.2.0 it's not the case:

```javascript
var path2regexp = require('path-to-regexp');
var re2 = path2regexp('', [], {end: false});
re2.exec('a/b'); // <-- returns null
```

The regexp for the root path in the prefix-matching mode does match _any absolute path_, which is what I expect:
```javascript
var re1 = path2regexp('/', [], {end: false});
re1.exec('/a/b'); // <-- returns a match
```

Live demo: https://runkit.com/vlukashov/path-to-regexp-2.2.0-with-an-empty-path

Could you please confirm whether or not you see this as an issue with path-to-regexp?
Issue
#148
Commit
761c721f9516d2739f87af3d303f5c096d1159d9
Why this commit
The first parent of the fix commit 28d2934b8ffecd70c590382ed22513112c873ca4, which GitHub binds to this issue via CLOSED_EVENT_PR. 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
path2regexp('', [], {end: false}).exec('a/b') produces null; the fix makes it produce [ '', groups: undefined, index: 0, input: 'a/b' ].
Expression
path2regexp('', [], {end: false}).exec('a/b')
Reported output
null
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: `path2regexp('', [], {end: false}).exec('a/b') //=> null`. The report sat in the ANNOTATION_IS_PROSE 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
`re2.exec('a/b')` still produces null (read null)
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`re2.exec('a/b')` still produces null (read null)
right-failurepassReproduced the reported failure: path2regexp('', [], {end: false}).exec('a/b') produces null; the fix makes it produce [ '', groups: undefined, index: 0, input: 'a/b' ].
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 761c721, 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/pillarjs/path-to-regexp
git checkout 761c721f9516d2739f87af3d303f5c096d1159d9
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