[Bug] Fix IPromise.finally() to await returned promises per ES2018 spec

[MSNev]

Promise.finally() was ignoring the return value of the onFinally callback. Per the ES2018 specification (ECMA-262 §27.2.5.3), if onFinally returns a promise/thenable, the resulting promise must wait for it to settle before propagating the original value or reason. If the returned promise rejects, that rejection must propagate.

Fixed in:

• lib/src/promise/base.ts (_finally implementation)
• lib/src/promise/await.ts (doFinally fallback when .finally is unavailable)
• lib/src/interfaces/types.ts (FinallyPromiseHandler type updated to allow PromiseLike)
• lib/src/interfaces/IPromise.ts (updated @param typedoc)

[Copilot]

Pull request overview

Fixes IPromise.finally() (and the doFinally fallback when native .finally is unavailable) to comply with ES2018 §27.2.5.3: when the onFinally callback returns a thenable, the resulting promise now waits for that thenable to settle before propagating the original value/reason, and if the returned thenable rejects, that rejection replaces the original outcome.

Changes:

• Updated _finally in lib/src/promise/base.ts to await a thenable returned from onFinally in both fulfilled and rejected paths.
• Updated the simulated-finally branch of doFinally in lib/src/promise/await.ts to do the same.
• Broadened FinallyPromiseHandler to allow () => PromiseLike<void> and refreshed the related TypeDoc on IPromise.finally.
• Refreshed transitive dependency versions in common/config/rush/npm-shrinkwrap.json (notably @nevware21/ts-preproc 0.1.4 → 0.1.5 with newer globby/ignore).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
lib/src/promise/base.ts	Await thenable returned by onFinally in both then/catch branches to comply with the spec.
lib/src/promise/await.ts	Mirror the same spec-compliant behavior in the doFinally simulated-finally fallback.
lib/src/interfaces/types.ts	Extend FinallyPromiseHandler to allow returning PromiseLike<void> and update the doc comment.
lib/src/interfaces/IPromise.ts	Update @param onfinally TypeDoc to describe the new async/awaiting semantics.
common/config/rush/npm-shrinkwrap.json	Lockfile refresh including @nevware21/ts-preproc 0.1.4→0.1.5 and related transitive bumps.

Files not reviewed (1)

• common/config/rush/npm-shrinkwrap.json: Language not supported

[codecov]

Codecov Report

❌ Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.96%. Comparing base (1e7a8f4) to head (60e3c77).

Files with missing lines	Patch %	Lines
lib/src/promise/await.ts	50.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #508      +/-   ##
==========================================
- Coverage   97.49%   96.96%   -0.54%     
==========================================
  Files          27       27              
  Lines        1439     1450      +11     
  Branches      338      341       +3     
==========================================
+ Hits         1403     1406       +3     
- Misses         36       44       +8     

Files with missing lines	Coverage Δ
lib/src/interfaces/IPromise.ts	50.00% <ø> (ø)
lib/src/interfaces/types.ts	50.00% <ø> (ø)
lib/src/promise/base.ts	98.98% <100.00%> (-0.01%)	⬇️
lib/src/promise/await.ts	91.83% <50.00%> (-8.17%)	⬇️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[Copilot]

Pull request overview

Copilot reviewed 9 out of 10 changed files in this pull request and generated 4 comments.

Files not reviewed (1)

• common/config/rush/npm-shrinkwrap.json: Language not supported