refactor: Replace deprecated semaphore with golang.org/x/sync/semaphore

[ovaistariq]

Summary

• Replaced custom semaphore implementation marked with TODO with standard golang.org/x/sync/semaphore package
• Updated test files to use the new NewSemaphore() constructor
• Added proper error handling for semaphore acquire operations

Changes Made

1. Removed deprecated code (core/utils.go):

   • Removed custom semaphore type based on channels
   • Removed empty struct that was only used by the semaphore
   • Eliminated TODO comment about replacing with standard library

2. Implemented modern semaphore (core/utils.go):

   • Created Semaphore struct wrapping golang.org/x/sync/semaphore.Weighted
   • Added NewSemaphore() constructor
   • Maintained same P() and V() API for backward compatibility
   • Added error handling for Acquire() calls (panics on error to maintain existing behavior)

3. Updated test usage (core/goofys_common_test.go):

   • Replaced make(semaphore, n) with NewSemaphore(n)
   • No other changes needed due to maintained API compatibility

Test Plan

• Code compiles successfully (go build)
• Static analysis passes (go vet)
• Linter passes (golangci-lint)
• Code formatting is correct (go fmt)
• Full test suite passes (requires cloud backend configuration)

This change eliminates technical debt and improves code maintainability by using the standard semaphore implementation.

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

Refactors the internal semaphore to use golang.org/x/sync/semaphore and updates tests to use the new constructor

• Removes custom channel-based semaphore and related types
• Introduces Semaphore wrapper around semaphore.Weighted with NewSemaphore, P, and V
• Updates test instantiations from make(semaphore, n) to NewSemaphore(n)

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
core/utils.go	Removed old semaphore type and added Semaphore wrapper with Acquire/Release
core/goofys_common_test.go	Replaced make(semaphore, ...) calls with NewSemaphore(...)

Comments suppressed due to low confidence (1)

core/utils.go:180

• Exported functions and types should have GoDoc comments. Please add a brief comment above NewSemaphore, Semaphore, P, and V explaining their purpose and behavior.

func NewSemaphore(n int64) *Semaphore {