fix(core): instantiate nested transient providers in static context

[mag123c]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

When a DEFAULT-scoped provider depends on a nested TRANSIENT chain (e.g., Controller → TransientA → TransientB), the nested TRANSIENT provider's constructor is not called. The instance exists as a prototype only, causing class fields to be undefined.

Issue Number: #16097

What is the new behavior?

Nested TRANSIENT providers are now properly instantiated in STATIC_CONTEXT. The isStatic() method now returns true when the inquirer is TRANSIENT with a static dependency tree and no rootInquirer set.

Does this PR introduce a breaking change?

• Yes
• No

Other information

Related PRs:

• fix(core): ensure nested transient provider isolation #15815: nested transient isolation in REQUEST scope
• fix(core): skip lifecycle hooks for non-instantiated transient services #15571: lifecycle hooks for non-instantiated transient

[coveralls]

Pull Request Test Coverage Report for Build c3b1f3ec-bdab-4a0e-a61d-21b32d8dc74b

Details

• 10 of 11 (90.91%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 89.685%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/core/injector/instance-wrapper.ts	10	11	90.91%

Totals
Change from base Build 486e7c70-dd96-4131-9d63-6cf55a189b18:	0.001%
Covered Lines:	7425
Relevant Lines:	8279

---

💛 - Coveralls

[kamilmysliwiec]

We might want to add an integration test, just in case - to ensure this doesn't happen again in the future

[kamilmysliwiec]

nit: i wonder if - instead of just adding another newline - it would have been better to break this down into if-else clauses with corresponding comments

[mag123c]

I agree, refactored the method with if-else clauses and comments for better readability.