fix(config): apply $production/$development layers when NODE_ENV is unset

[jlgrimes]

🔗 Linked issue

Resolves #3052

❓ Type of change

• 🐞 Bug fix (a non-breaking change that fixes an issue)

📚 Description

Nitro uses c12 for config loading, but when NODE_ENV is unset it currently forwards no envName, so c12 skips $production and $development layers entirely.

This causes production deployments (e.g. Cloudflare Pages) to ignore $production config blocks unless NODE_ENV is manually set.

What changed

• Default c12 envName from configOverrides.dev:
  • development when dev: true
  • production when dev: false
• Keep opts.c12.envName override support intact (explicit override still wins).
• Added regression tests that verify both $production and $development layers are applied correctly when NODE_ENV is unset.

Validation

• pnpm vitest test/unit/config-loader-env.test.ts

[vercel]

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[coderabbitai]

📝 Walkthrough

Walkthrough

The changes introduce an envName parameter to the config loader that defaults to "development" or "production" based on the dev flag, enabling environment-based configuration layers to function without requiring NODE_ENV to be set. Unit tests validate the correct layer application based on the dev flag.

Changes

Cohort / File(s)	Summary
Configuration Loader Enhancement src/config/loader.ts	Adds envName parameter derived from opts.c12?.envName with default fallback to "development" (when dev is true) or "production", passed to loadConfig call.
Environment Layer Tests test/unit/config-loader-env.test.ts	Introduces comprehensive unit tests for environment-based config layers, including fixture creation with multi-layer configurations ($production, $development, base) and tests verifying correct layer application based on NODE_ENV and dev flag states.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% 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
Title check	✅ Passed	The pull request title 'fix(config): apply $production/$development layers when NODE_ENV is unset' follows conventional commits format with a clear fix prefix and descriptive summary of the change.
Description check	✅ Passed	The pull request description is well-related to the changeset, explaining the issue, what changed, and providing validation details about environment layer application.
Linked Issues check	✅ Passed	The PR successfully addresses issue #3052 by implementing envName defaults (development/production) based on dev flag when NODE_ENV is unset, with regression tests verifying both layers are applied correctly.
Out of Scope Changes check	✅ Passed	All changes are in scope: environment layer defaulting logic in src/config/loader.ts and comprehensive regression tests in test/unit/config-loader-env.test.ts directly address the linked issue requirements.

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✨ Finishing Touches

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• Post copyable unit tests in a comment

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[coderabbitai]

🧹 Nitpick comments (1)

test/unit/config-loader-env.test.ts (1)

60-61: Consider verifying base layer is preserved alongside env layer.

The fixture defines a base /base route. Adding an assertion for it would confirm that env-specific layers are merged correctly without losing base configuration.

💡 Optional enhancement

     expect(options.routeRules["/prod"]?.headers?.["x-env"]).toBe("production");
     expect(options.routeRules["/dev"]).toBeUndefined();
+    expect(options.routeRules["/base"]?.headers?.["x-env"]).toBe("base");
   });

   it("applies $development when NODE_ENV is unset and dev=true", async () => {
     // ...
     expect(options.routeRules["/dev"]?.headers?.["x-env"]).toBe("development");
     expect(options.routeRules["/prod"]).toBeUndefined();
+    expect(options.routeRules["/base"]?.headers?.["x-env"]).toBe("base");
   });

Also applies to: 71-72

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@test/unit/config-loader-env.test.ts` around lines 60 - 61, Add assertions
that the base route from the fixture is still present after env layering: check
options.routeRules["/base"] exists and its original properties (e.g., headers,
upstreams, or whatever the fixture defines) match expected values to ensure the
env layer merged rather than replaced the base layer; update both places where
routeRules for env tests are asserted (the blocks that currently check
"/prod"/"/dev") to include these "/base" assertions referencing
options.routeRules.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@test/unit/config-loader-env.test.ts`:
- Around line 60-61: Add assertions that the base route from the fixture is
still present after env layering: check options.routeRules["/base"] exists and
its original properties (e.g., headers, upstreams, or whatever the fixture
defines) match expected values to ensure the env layer merged rather than
replaced the base layer; update both places where routeRules for env tests are
asserted (the blocks that currently check "/prod"/"/dev") to include these
"/base" assertions referencing options.routeRules.

---

ℹ️ Review info

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bfbb207 and 395a111.

📒 Files selected for processing (2)

• src/config/loader.ts
• test/unit/config-loader-env.test.ts