fix: dev serverfn resolution on windows

[schiller-manuel]

Summary by CodeRabbit

• Chores
  • Internal improvements to server function handling and file path normalization to enhance system reliability.

[coderabbitai]

Walkthrough

Server function ID generation in dev environments now normalizes trailing slashes via a helper function and adjusts file path computation to construct routes with leading slash prefixes. Concurrently, the fake manifest's getServerFnById function transitions from synchronous to asynchronous with a Promise return type.

Changes

Cohort / File(s)	Summary
Server function path normalization packages/server-functions-plugin/src/index.ts	Adds withTrailingSlash() helper for trailing slash normalization; updates generateFunctionId to compute root from serverDevEnv.config.root, strip root prefix from filename, and construct file path with leading slash (e.g., /@id...); updates serverFn.file accordingly
Fake manifest async transition packages/start-server-core/src/fake-start-server-fn-manifest.ts	Changes getServerFnById from synchronous to asynchronous, updating signature to export async function getServerFnById(): Promise<any> {}

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~15 minutes

Possibly related PRs

• fix: no invalidation for server functions in dev #5513 — Modifies the server-functions pipeline including generateFunctionId and fake manifest behavior for server function resolution
• Add support for customizable functionId generation. #5373 — Updates server-functions-plugin path and ID generation logic for server function route construction

Poem

🐰 With trailing slashes trimmed so neat,
And async paths that now compete,
The rabbit hops through routes divine,
Where /@id marks the dev-time line! ✨

Pre-merge checks and finishing touches

❌ 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%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The PR title "fix: dev serverfn resolution on windows" directly relates to the primary change in the changeset. The modifications focus on updating how server function file paths are resolved in the server-dev environment, specifically by introducing path normalization logic (withTrailingSlash helper) and adjusting filename handling when computing the file identifier. The title is specific and meaningful—it indicates this is a bug fix for server function resolution in dev mode on Windows, which aligns with the source branch name "fix-serverfn-win" and the platform-specific path handling logic evident in the changes. A developer scanning the repository history would understand this addresses a Windows-specific issue with server function resolution during development.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix-serverfn-win

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---

☁️ Nx Cloud last updated this comment at 2025-10-17 22:09:21 UTC

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commit: f535282

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 7d8e105 and f535282.

📒 Files selected for processing (2)

• packages/server-functions-plugin/src/index.ts (1 hunks)
• packages/start-server-core/src/fake-start-server-fn-manifest.ts (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

**/*.{ts,tsx}

📄 CodeRabbit inference engine (AGENTS.md)

Use TypeScript in strict mode with extensive type safety across the codebase

Files:

• packages/start-server-core/src/fake-start-server-fn-manifest.ts
• packages/server-functions-plugin/src/index.ts

packages/{*-start,start-*}/**

📄 CodeRabbit inference engine (AGENTS.md)

Name and place Start framework packages under packages/-start/ or packages/start-/

Files:

• packages/start-server-core/src/fake-start-server-fn-manifest.ts

🧬 Code graph analysis (2)

packages/start-server-core/src/fake-start-server-fn-manifest.ts (1)

packages/start-server-core/src/getServerFnById.ts (1)

• getServerFnById (1-1)

packages/server-functions-plugin/src/index.ts (1)

packages/directive-functions-plugin/src/compilers.ts (1)

• GenerateFunctionIdFn (26-30)

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• GitHub Check: Preview
• GitHub Check: Test

🔇 Additional comments (3)

packages/server-functions-plugin/src/index.ts (3)

71-76: LGTM! Clean helper for path normalization.

The withTrailingSlash helper correctly ensures a trailing slash on paths, which is essential for consistent path prefix matching on different platforms.

---

96-96: Correct application of normalized path.

Using the computed file value instead of extractedFilename ensures the server function receives the properly normalized path with the /@id prefix for module resolution.

---

83-91: Verify path normalization handles Windows edge cases.

The path normalization logic looks sound—using withTrailingSlash(root) for the prefix check while slicing by root.length (without trailing slash) correctly preserves the leading slash. However, please verify:

1. Edge case: If extractedFilename equals root exactly, file becomes empty and line 90 produces "/@id/". Confirm this is handled appropriately.
2. Windows paths: Ensure that both serverDevEnv.config.root and extractedFilename are normalized to forward slashes by Vite before this code runs, as mixing backslashes and forward slashes would break the startsWith check.

[coderabbitai]

⚠️ Potential issue | 🔴 Critical

Missing required parameter in function signature.

The fake implementation is missing the id parameter that the real implementation includes (see packages/server-functions-plugin/src/index.ts lines 191 and 211). Even though this is a stub, the signature should match to maintain type consistency and prevent runtime errors if this fake is accidentally invoked.

Apply this diff to fix the signature:

-export async function getServerFnById(): Promise<any> {}
+export async function getServerFnById(id: string): Promise<any> {}

Additionally, consider tightening the return type from Promise<any> to be more specific if the actual return type is known.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

	export async function getServerFnById(): Promise<any> {}
	export async function getServerFnById(id: string): Promise<any> {}

🤖 Prompt for AI Agents

In packages/start-server-core/src/fake-start-server-fn-manifest.ts around line
1, the exported async function is missing the required id parameter present in
the real implementation; update the function signature to accept the same id
parameter (and any other parameters that the real implementation defines at
lines 191 and 211 in packages/server-functions-plugin/src/index.ts) so the stub
matches the real API, and tighten the return type from Promise<any> to the
actual return type if known (or to a more specific union/interface) to maintain
type consistency and avoid runtime/typing surprises.