fix(wrap): correctly detect single balanced group (#549)

[MukundaKatta]

Summary

Fixes #549 — `maybe()` / `optionally()` incorrectly handled named captures.

`wrap()` decided whether a value was already grouped via:

```ts
const NO_WRAP_RE = /^(?:(.*)|\?.)$/
```

That check only looks at the first and last characters. A concatenation such as `(?:[-_.])?(?\d+)` starts with `(` and ends with `)` but is really two adjacent atoms, so `wrap()` skipped grouping it. The final `?` from `maybe` then bound to the trailing named capture alone:

```
/(?:beta|dev)(?:[-.])?(?\d+)?/gi // before
/(?:beta|dev)(?:(?:[-.])?(?\d+))?/gi // after
```

Replaced the regex with a small balance-aware scan (`isSingleGroup`) that returns true only when the value is a single parenthesised group spanning from the first `(` to the last `)`. Character classes are skipped so literal `[(]` / `[)]` don't unbalance the count; escaped characters are also skipped.

Test plan

• Added a regression case in `test/inputs.test.ts` using the exact pattern from the issue.
• `pnpm test` — 105/105 tests pass (inline snapshots for existing `maybe` / `oneOrMore` cases like `maybe(exactly('foo').groupedAs('groupName'))` → `(?foo)?` unchanged).
• `pnpm lint` clean.
• Manual repro from the issue now matches `Beta` in `-Beta.zip` under both patterns.

Summary by CodeRabbit

• Bug Fixes

  • Fixed pattern wrapping behavior for complex regular expressions containing concatenations and parenthesized groups.

• Tests

  • Added regression test for optional group wrapping with named captures.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: f87f7d1d-2046-4fc7-9451-70a1ce37c078

📥 Commits

Reviewing files that changed from the base of the PR and between 5805a8c and c28a46f.

📒 Files selected for processing (2)

• src/core/wrap.ts
• test/inputs.test.ts

---

📝 Walkthrough

Walkthrough

This pull request fixes the wrap() function to correctly handle inputs that start with ( and end with ). It replaces a single regex-based check with a two-part predicate that includes a new isSingleGroup() helper to verify whether a string is truly a single balanced parenthesized group. This resolves incorrect wrapping behavior in maybe()/optionally() when named capture groups are present.

Changes

Cohort / File(s)	Summary
Core wrap logic src/core/wrap.ts	Replaced regex-based "don't wrap" check (`/^(?:(.*)
Regression test test/inputs.test.ts	Added test case for maybe() with a named capture group (via .as('number')), verifying that the entire concatenation wraps into a single optional non-capturing group rather than applying optionality to individual components.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A hop, a skip, a fix so neat,
Now maybe() groups are quite complete,
No more fragments left alone,
One wrapped unit—the bug is gone!
Magic regexps dance as one. ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main fix: correcting single balanced group detection in the wrap function to resolve the maybe()/optionally() issue.
Linked Issues check	✅ Passed	The PR directly addresses issue #549 by replacing the flawed regex-based check with a balance-aware isSingleGroup predicate that correctly detects when content is a single parenthesized group, fixing the incorrect wrapping of maybe() with named captures.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the wrap function logic and adding a regression test; no unrelated modifications are present.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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