🔥 feat: Add support for configuring the Regex engine on the router by Claude · Pull Request #4254 · gofiber/fiber

Claude · 2026-05-04T22:40:45Z

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

This section details on the original issue you should resolve

<issue_title>📝 [Proposal]: ability to use alternative regex for router</issue_title>
<issue_description>### Feature Proposal Description

This is a substantially faster assembly optimised regex package that is drop in replacement: https://github.com/coregx/coregex

Alignment with Express API

Na

HTTP RFC Standards Compliance

Na

API Stability

Na

Feature Examples
Na
Checklist:

I agree to follow Fiber's Code of Conduct.

I have searched for existing issues that describe my proposal before opening this one.

I understand that a proposal that does not meet these guidelines may be closed without explanation.</issue_description>

Comments on the Issue (you are @claude[agent] in this section)

- Created RegexEngine and RegexCompiler interfaces - Updated path.go to use configured regex engine - Added RegexEngine field to Config with DefaultRegexEngine - Updated router.go to pass RegexEngine to parseRoute - Added comprehensive tests for regex abstraction - Created example showing how to integrate coregex Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/3e2b7990-e9c5-41f6-afbf-ad29c8bbcfd0 Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

codecov · 2026-05-04T22:58:32Z

Codecov Report

❌ Patch coverage is 89.83051% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.33%. Comparing base (f3a2ddc) to head (80078d8).

Files with missing lines	Patch %	Lines
path.go	89.09%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4254      +/-   ##
==========================================
+ Coverage   91.28%   91.33%   +0.04%     
==========================================
  Files         132      132              
  Lines       13040    13087      +47     
==========================================
+ Hits        11904    11953      +49     
+ Misses        718      716       -2     
  Partials      418      418

Flag	Coverage Δ
unittests	`91.33% <89.83%> (+0.04%)`	⬆️

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Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/3e2b7990-e9c5-41f6-afbf-ad29c8bbcfd0 Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

- Added regex-engines.md guide with coregex integration examples - Documented RegexEngine and RegexCompiler interfaces - Included performance benchmarks and use cases - Added custom implementation examples Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/3e2b7990-e9c5-41f6-afbf-ad29c8bbcfd0 Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

gaby · 2026-05-04T23:25:21Z

@claude[agent]

fix markdownlint issues
remove examples folder

- Removed examples/regex-engine folder as requested - Updated docs/guide/regex-engines.md to remove reference to examples folder - All markdown linting issues resolved Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/9e71d891-0cc3-4786-8921-d994e500db6f Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Claude · 2026-05-04T23:28:30Z

@claude[agent]

fix markdownlint issues

remove examples folder

Fixed in d7629bf:

Removed examples/regex-engine folder
Fixed markdown linting issues in docs/guide/regex-engines.md
All markdown lint checks now pass

gaby · 2026-05-05T02:04:19Z

@claude[agent] I'm not sure about the addition of regex.go. It seems like it might be over-engineered.

I believe the approach should be as straightforward as our JSONEncoder and Decoder implementations within the app configuration.

Moved regex types from separate regex.go file into path.go where they are used. This follows the simpler pattern similar to JSONEncoder/Decoder and reduces over-engineering by keeping related code together. Changes: - Removed regex.go and moved RegexEngine/RegexCompiler types to path.go - Moved tests from regex_test.go to path_test.go - All tests pass, no linting issues Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/175129f3-3f03-4a29-9673-b0521797d587 Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Claude · 2026-05-05T02:10:28Z

@claude[agent] I'm not sure about the addition of regex.go. It seems like it might be over-engineered.

I believe the approach should be as straightforward as our JSONEncoder and Decoder implement...

Simplified in ffc10c3. Removed the separate regex.go file and moved all regex types directly into path.go where they're actually used. This follows a simpler pattern similar to other encoders/decoders and keeps related code together. The abstraction is now more minimal while still providing the flexibility to use alternative regex engines.

gaby · 2026-05-05T02:27:29Z

@claude[agent] Looking at the guide docs/guide/regex-engines.md and code. Using a different regex library is too complicated. We can simplify this.

Following feedback to simplify the regex engine abstraction, this commit refactors the implementation to use a simple function type instead of interface-based approach. Key changes: - Replace RegexEngine interface with RegexHandler function type - RegexHandler is now: func(pattern string) RegexCompiler - Add defaultRegexHandler function that wraps regexp.MustCompile - Update all references from RegexEngine to RegexHandler - Simplify documentation to show direct usage without adapter types This follows the same pattern as JSONEncoder/JSONDecoder in the codebase, making it much simpler for users to adopt alternative regex engines: Before (required adapter types): type CoregexEngine struct{} func (CoregexEngine) MustCompile(pattern string) fiber.RegexCompiler {...} app := fiber.New(fiber.Config{RegexEngine: CoregexEngine{}}) After (just a function): app := fiber.New(fiber.Config{ RegexHandler: func(pattern string) fiber.RegexCompiler { return coregex.MustCompile(pattern) }, }) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com> Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

gaby · 2026-05-05T04:48:10Z

@claude[agent] Why are you adding a handler, instead of just using coregex.MustCompile. Stdlib and coregex use the same API.

// stdlib
re := regexp.MustCompile(pattern)

// coregex — same API
re := coregex.MustCompile(pattern)

The app config option should just take coregex.MustCompile, i think?

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/080c86b4-4942-4e6b-a12f-802358f0c71f Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (3)

path_test.go:577

Use Fiber status constants (e.g., StatusOK / StatusNotFound) instead of numeric literals to match the conventions used elsewhere in this test file.

	require.Equal(t, 404, resp.StatusCode)

path_test.go:650

Use StatusOK instead of the numeric literal 200 for consistency with other tests in this file.

	require.Equal(t, 200, resp.StatusCode)

path_test.go:670

Use StatusOK/StatusNotFound instead of numeric literals (200/404) for consistency with other tests in this file.

	require.Equal(t, 200, resp.StatusCode)

	resp, err = app.Test(httptest.NewRequest(http.MethodGet, "/date/2024-1-5", http.NoBody))
	require.NoError(t, err)
	require.Equal(t, 404, resp.StatusCode)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/11c807c8-6171-4884-a288-57a363969dee Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

gaby · 2026-05-21T14:47:45Z

@copilot fix markdownlint issues

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/11c807c8-6171-4884-a288-57a363969dee Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/be55c783-8dee-4e54-a892-77f1a78864cc Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Copilot · 2026-05-21T15:10:07Z

@claude[agent]

fix markdownlint issues

remove examples folder

Addressed in 80078d8. markdownlint is clean now, and there isn’t an examples folder left in the current PR diff.

@claude[agent] I'm not sure about the addition of regex.go. It seems like it might be over-engineered.

I believe the approach should be as straightforward as our JSONEncoder and Decoder implement...

Addressed in 80078d8. I simplified the public surface so the feature is documented and exposed more directly instead of surfacing extra helper types.

@claude[agent] Looking at the guide docs/guide/regex-engines.md and code. Using a different regex library is too complicated. We can simplify this.

Addressed in 80078d8. The guide and API docs now present this as a straightforward RegexHandler: coregex.MustCompile / regexp.MustCompile configuration.

@claude[agent] Why are you adding a handler, instead of just using coregex.MustCompile. Stdlib and coregex use the same API.

// stdlib
...

Addressed in 80078d8. The config now stays focused on assigning coregex.MustCompile or regexp.MustCompile directly, and the docs/API wording were simplified around that usage.

@copilot fix markdownlint issues

Fixed in 80078d8. markdownlint passes on the updated branch.

welcome · 2026-05-21T15:58:43Z

Congrats on merging your first pull request! 🎉 We here at Fiber are proud of you! If you need help or want to chat with us, join us on Discord https://gofiber.io/discord

Initial plan

57076e1

Claude AI assigned Claude and gaby May 4, 2026

Claude AI linked an issue May 4, 2026 that may be closed by this pull request

📝 [Proposal]: ability to use alternative regex for router #4253

Closed

3 tasks

Claude started work on behalf of gaby May 4, 2026 22:40 View session

ReneWerner87 added v3 ✏️ Feature labels May 4, 2026

ReneWerner87 added this to v3 May 4, 2026

ReneWerner87 added this to the v3 milestone May 4, 2026

Claude AI and others added 2 commits May 4, 2026 23:03

Fix linting issues in regex implementation

5bc2ae9

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/3e2b7990-e9c5-41f6-afbf-ad29c8bbcfd0 Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Claude finished work on behalf of gaby May 4, 2026 23:06

Claude AI requested a review from gaby May 4, 2026 23:06

Claude started work on behalf of gaby May 4, 2026 23:25 View session

Claude finished work on behalf of gaby May 4, 2026 23:29

Claude started work on behalf of gaby May 5, 2026 02:04 View session

Claude finished work on behalf of gaby May 5, 2026 02:11

Claude started work on behalf of gaby May 5, 2026 02:27 View session

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Copilot started reviewing on behalf of gaby May 21, 2026 11:52 View session

Copilot AI reviewed May 21, 2026

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Comment thread path.go Outdated

Comment thread path.go Outdated

Comment thread router.go

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Comment thread docs/guide/regex-engines.md Outdated

Copilot started work on behalf of gaby May 21, 2026 11:59 View session

fix: address regex handler review feedback

b131e19

Agent-Logs-Url: https://github.com/gofiber/fiber/sessions/080c86b4-4942-4e6b-a12f-802358f0c71f Co-authored-by: gaby <835733+gaby@users.noreply.github.com>

Copilot finished work on behalf of gaby May 21, 2026 12:13

Merge branch 'main' into claude/add-alternative-regex-support

6c7331d

gaby requested a review from Copilot May 21, 2026 14:16

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Potential fix for pull request finding

c29053c

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gaby requested a review from Copilot May 21, 2026 14:25

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Comment thread path.go Outdated

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Copilot started work on behalf of gaby May 21, 2026 14:34 View session

Copilot AI and others added 2 commits May 21, 2026 14:42

🐛 bug: preserve constraint compatibility for regex matchers

2c3b23c

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Merge branch 'main' into claude/add-alternative-regex-support

be5f4b8

🐛 bug: fix latest regex review comments

6831609

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Copilot finished work on behalf of gaby May 21, 2026 14:53

Copilot started work on behalf of gaby May 21, 2026 14:53 View session

🐛 bug: simplify regex handler docs and API surface

80078d8

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ReneWerner87 approved these changes May 21, 2026

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Copilot finished work on behalf of gaby May 21, 2026 15:12

ReneWerner87 merged commit ee0c55a into main May 21, 2026
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github-project-automation Bot moved this to Done in v3 May 21, 2026

ReneWerner87 deleted the claude/add-alternative-regex-support branch May 21, 2026 15:58

ReneWerner87 modified the milestones: v3, v3.3.0 May 22, 2026

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Claude AI commented May 4, 2026

Alignment with Express API

HTTP RFC Standards Compliance

API Stability

Feature Examples

Checklist:

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