Description

Replace map[int]bool with map[int]struct{} for the cacheableStatusCodes set.

Why?

map[int]struct{} is the idiomatic Go pattern for representing sets (collections where only key presence matters).
It reduces memory usage slightly by avoiding storage of unnecessary boolean values (struct{} is zero-sized).
Benchmarking confirms:

• Lower memory footprint (B/op) at scale
• Same allocation count and runtime performance
• Clearer intent: emphasizes that we only care about membership, not associated values

package main

import (
	"testing"

	"github.com/gofiber/fiber/v2"
)

const numEntries = 100000 // Try 100, 1000, 10000 to see scaling

var statusCodes = []int{
	fiber.StatusOK,
	fiber.StatusNonAuthoritativeInformation,
	fiber.StatusNoContent,
	fiber.StatusPartialContent,
	fiber.StatusMultipleChoices,
	fiber.StatusMovedPermanently,
	fiber.StatusNotFound,
	fiber.StatusMethodNotAllowed,
	fiber.StatusGone,
	fiber.StatusRequestURITooLong,
	fiber.StatusNotImplemented,
}

func fillMapBool(m map[int]bool) {
	for i := range numEntries {
		code := statusCodes[i%len(statusCodes)]
		m[code+(i/len(statusCodes))*1000] = true
	}
}

func fillMapStruct(m map[int]struct{}) {
	for i := range numEntries {
		code := statusCodes[i%len(statusCodes)]
		m[code+(i/len(statusCodes))*1000] = struct{}{}
	}
}

// BenchmarkMapBool measures map[int]bool allocation
func BenchmarkMapBool(b *testing.B) {
	b.ReportAllocs()
	for b.Loop() {
		m := make(map[int]bool, numEntries)
		fillMapBool(m)
		_ = m
	}
}

// BenchmarkMapStruct measures map[int]struct{} allocation
func BenchmarkMapStruct(b *testing.B) {
	b.ReportAllocs()
	for b.Loop() {
		m := make(map[int]struct{}, numEntries)
		fillMapStruct(m)
		_ = m
	}
}

Custom Demo Benchmark:

Bencmark_Cache (BEFORE):

Bencmark_Cache (AFTER):

Impact:

• No functional or behavioral changes
• Fully backward-compatible
• Aligns codebase with Go best practices
• This is a small, safe cleanup that improves code clarity and efficiency.

Changes introduced

List the new features or adjustments introduced in this pull request. Provide details on benchmarks, documentation updates, changelog entries, and if applicable, the migration guide.

• Benchmarks: Describe any performance benchmarks and improvements related to the changes.
• Documentation Update: Detail the updates made to the documentation and links to the changed files.
• Changelog/What's New: Include a summary of the additions for the upcoming release notes.
• Migration Guide: If necessary, provide a guide or steps for users to migrate their existing code to accommodate these changes.
• API Alignment with Express: Explain how the changes align with the Express API.
• API Longevity: Discuss the steps taken to ensure that the new or updated APIs are consistent and not prone to breaking changes.
• Examples: Provide examples demonstrating the new features or changes in action.

Type of change

Please delete options that are not relevant.

• Performance improvement (non-breaking change which improves efficiency)
• Code consistency (non-breaking change which improves code reliability and robustness)

Checklist

Before you submit your pull request, please make sure you meet these requirements:

• Followed the inspiration of the Express.js framework for new functionalities, making them similar in usage.
• Conducted a self-review of the code and provided comments for complex or critical parts.
• Updated the documentation in the /docs/ directory for Fiber's documentation.
• Added or updated unit tests to validate the effectiveness of the changes or new features.
• Ensured that new and existing unit tests pass locally with the changes.
• Verified that any new dependencies are essential and have been agreed upon by the maintainers/community.
• Aimed for optimal performance with minimal allocations in the new code.
• Provided benchmarks for the new code to analyze and improve upon.

Commit formatting

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