docs: improve deprecated comments; use go:fix inline

[alexandear]

This PR improves deprecated functions:

• Now godoc links are clickable.
• Now we can use go fix -inline to automatically migrate, see https://go.dev/blog/inliner.

Before:

After:

Summary by CodeRabbit

• Refactor
  • Updated deprecation notices for ToLowerBytes, ToUpperBytes, ToLower, and ToUpper functions with direct references to their replacements in the new utility package location. Users should migrate to the updated function paths for continued support.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the developer experience when dealing with deprecated utility functions. It updates the deprecation notices to provide clickable links to the recommended replacement functions in godoc, making it easier for users to navigate to the correct alternatives. Additionally, it introduces go:fix inline directives, enabling automated code migration for these deprecated functions, streamlining the update process for users.

Highlights

• Improved Deprecation Comments: Deprecation comments for ToLowerBytes, ToUpperBytes, ToLower, and ToUpper functions were updated to use the new Go documentation link format, making them clickable in godoc.
• Enabled go fix -inline Migration: The go:fix inline directive was added to the deprecated functions, allowing users to automatically migrate their code using go fix -inline.

Changelog

• bytes.go
  • Updated ToLowerBytes deprecation comment to use [github.com/gofiber/utils/v2/bytes.UnsafeToLower] and added //go:fix inline.
  • Updated ToUpperBytes deprecation comment to use [github.com/gofiber/utils/v2/bytes.UnsafeToUpper] and added //go:fix inline.
• strings.go
  • Updated ToLower deprecation comment to use [github.com/gofiber/utils/v2/strings.ToLower] and added //go:fix inline.
  • Updated ToUpper deprecation comment to use [github.com/gofiber/utils/v2/strings.ToUpper] and added //go:fix inline.

Activity

• No human activity has been recorded on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request updates the deprecation notices for several functions in bytes.go and strings.go. The changes include updating the Deprecated comments to a format that generates clickable links in godoc, and adding the //go:fix inline directive to enable automatic code migration via go fix. The implementation aligns with the recommendations for using these Go features. No issues were found in the changes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 31eec824-2386-4fbe-8ac8-ea2c7a57220b

📥 Commits

Reviewing files that changed from the base of the PR and between ca61051 and a6f83d2.

📒 Files selected for processing (2)

• bytes.go
• strings.go

📜 Recent review details

🔇 Additional comments (4)

strings.go (2)

11-18: LGTM!

//go:fix inline directive enables "self-service API migration and upgrades." The deprecation comment uses the correct bracket link syntax for clickable godoc links, and the wrapper function (single return statement) is ideal for automated inlining. The signature matches the target strings.ToLower(s string) string from the context snippet.

---

20-27: LGTM!

Consistent with ToLower — correct bracket link format for godoc, valid //go:fix inline placement, and compatible signature with strings.ToUpper. The changes enable automated migration via go fix.

bytes.go (2)

11-19: LGTM!

The deprecation message now uses the clickable bracket link format while retaining the important backward compatibility note about slice mutation. The //go:fix inline directive enables "library authors to mark functions for automatic call-site inlining during migrations." The wrapper is a single return statement delegating to casebytes.UnsafeToLower, making it ideal for inlining with compatible signatures.

---

21-29: LGTM!

Consistent with ToLowerBytes — correct bracket link format, retained compatibility note, and valid //go:fix inline placement. The changes enable automated migration via go fix.

---

Walkthrough

Updates deprecation comments and adds //go:fix inline directives to utility functions in bytes and strings modules, guiding developers toward newer unsafe variants without altering any functionality.

Changes

Cohort / File(s)	Summary
Deprecation and Go Fix Updates bytes.go, strings.go	Updated deprecation comments to reference bracketed function paths (UnsafeToLower/UnsafeToUpper) and added //go:fix inline directives to facilitate automated migration of callers.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~5 minutes

Possibly related PRs

• semantics: explicit mutating APIs, safe replacements #186: Refactors and delegates ToLower/ToUpper and ToLowerBytes/ToUpperBytes functions to new unsafe/non-mutating variants that this PR now references in deprecation notices.
• Improve utils performance #116: Modifies the implementations of the same ToLower/ToUpper functions being deprecated in this PR for performance improvements.
• refactor: update utils and add go 1.26 for test workflow fiber#4087: Introduces and renames UnsafeToLower/UnsafeToUpper functions that are the target replacements referenced in the updated deprecation comments.

Suggested labels

🧹 Updates

Suggested reviewers

• ReneWerner87
• sixcolors
• gaby

Poem

🐰 The bytes and strings hop along with care,
Their deprecation notes now guide you there!
Go:fix directives point the weary way,
To unsafe variants, bright and gay! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 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 changes: improving deprecated comments and adding go:fix inline directives to enable automated migration.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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