Consolidate duplicate SetGatewayVersion implementations

[Copilot]

Semantic analysis identified SetGatewayVersion duplicated across 3 packages (config, server, mcp) with 100% identical implementations, creating multiple sources of truth for version state.

Changes

New package: internal/version

• Set(v string) - updates gateway version if non-empty
• Get() string - returns current version
• Single initialization point from cmd.SetVersion()

Removed duplicates:

• config.SetGatewayVersion()
• server.SetGatewayVersion()
• mcp.SetClientGatewayVersion()

Updated call sites:

• Config validation error messages: version.Get()
• Health endpoint response: version.Get()
• MCP client implementation info: version.Get()

Naming conflict resolution:

• Renamed cmd.version → cmd.cliVersion to avoid collision with package name
• Both cliVersion and version.Get() synchronized via SetVersion()

Implementation

// Before: Multiple sources of truth
config.SetGatewayVersion(v)
server.SetGatewayVersion(v)
mcp.SetClientGatewayVersion(v)

// After: Single source of truth
version.Set(v)

Version state is write-once at startup before concurrent access, read-only thereafter.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• example.com
  • Triggering command: /tmp/go-build3413136910/b271/launcher.test /tmp/go-build3413136910/b271/launcher.test -test.testlogfile=/tmp/go-build3413136910/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true -c=4 -nolocalimports -importcfg /tmp/go-build3390212890/b209/importcfg -pack /home/REDACTED/work/gh-aw-mcpg/gh-aw-mcpg/internal/auth/header.go 64/pkg/tool/linu/tmp/go-build2415659088/b165/vet.cfg conf�� g_.a H6RJmYT_A cal/bin/bash credential.usern/opt/hostedtoolcache/go/1.25.6/x64/pkg/tool/linux_amd64/compile go (dns block)
  • Triggering command: /tmp/go-build1107041789/b275/launcher.test /tmp/go-build1107041789/b275/launcher.test -test.testlogfile=/tmp/go-build1107041789/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s 5659�� 5659088/b186/_pkg_.a .cfg 64/pkg/tool/linux_amd64/vet (dns block)
  • Triggering command: /tmp/go-build1825466283/b275/launcher.test /tmp/go-build1825466283/b275/launcher.test -test.testlogfile=/tmp/go-build1825466283/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go1.25.6 -c=4 -nolocalimports -importcfg /tmp/go-build1825466283/b263/importcfg -pack /tmp/go-build1825466283/b263/_testmain.go --ve�� (dns block)
• invalid-host-that-does-not-exist-12345.com
  • Triggering command: /tmp/go-build3413136910/b259/config.test /tmp/go-build3413136910/b259/config.test -test.testlogfile=/tmp/go-build3413136910/b259/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true -c=4 -nolocalimports -importcfg /tmp/go-build3390212890/b227/importcfg -pack /home/REDACTED/go/pkg/mod/github.com/!burnt!sushi/toml@v1.6.0/decode.go /home/REDACTED/go/pkg/mod/github.com/!burnt!sushi/toml@v1.6.0/deprecated.go conf�� go --global nfig/composer/vendor/bin/git credential.usern/opt/hostedtoolcache/go/1.25.6/x64/pkg/tool/linux_amd64/compile (dns block)
  • Triggering command: /tmp/go-build1107041789/b263/config.test /tmp/go-build1107041789/b263/config.test -test.testlogfile=/tmp/go-build1107041789/b263/testlog.txt -test.paniconexit0 -test.timeout=10m0s fetc�� 64/src/runtime/cgo main x_amd64/vet (dns block)
  • Triggering command: /tmp/go-build1825466283/b263/config.test /tmp/go-build1825466283/b263/config.test -test.testlogfile=/tmp/go-build1825466283/b263/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true --version /home/REDACTED/work/gh-aw-mcpg/gh-aw-mcpg/internal/config/config_feature.go ndor/bin/bash g_.a o ndor/bin/as grep -qE (create|run) ortcfg ash 64/src/runtime/c/opt/hostedtoolcache/go/1.25.6/x64/pkg/tool/linux_amd64/vet w52HAkEye x_amd64/vet bash (dns block)
• nonexistent.local
  • Triggering command: /tmp/go-build3413136910/b271/launcher.test /tmp/go-build3413136910/b271/launcher.test -test.testlogfile=/tmp/go-build3413136910/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true -c=4 -nolocalimports -importcfg /tmp/go-build3390212890/b209/importcfg -pack /home/REDACTED/work/gh-aw-mcpg/gh-aw-mcpg/internal/auth/header.go 64/pkg/tool/linu/tmp/go-build2415659088/b165/vet.cfg conf�� g_.a H6RJmYT_A cal/bin/bash credential.usern/opt/hostedtoolcache/go/1.25.6/x64/pkg/tool/linux_amd64/compile go (dns block)
  • Triggering command: /tmp/go-build1107041789/b275/launcher.test /tmp/go-build1107041789/b275/launcher.test -test.testlogfile=/tmp/go-build1107041789/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s 5659�� 5659088/b186/_pkg_.a .cfg 64/pkg/tool/linux_amd64/vet (dns block)
  • Triggering command: /tmp/go-build1825466283/b275/launcher.test /tmp/go-build1825466283/b275/launcher.test -test.testlogfile=/tmp/go-build1825466283/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go1.25.6 -c=4 -nolocalimports -importcfg /tmp/go-build1825466283/b263/importcfg -pack /tmp/go-build1825466283/b263/_testmain.go --ve�� (dns block)
• slow.example.com
  • Triggering command: /tmp/go-build3413136910/b271/launcher.test /tmp/go-build3413136910/b271/launcher.test -test.testlogfile=/tmp/go-build3413136910/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true -c=4 -nolocalimports -importcfg /tmp/go-build3390212890/b209/importcfg -pack /home/REDACTED/work/gh-aw-mcpg/gh-aw-mcpg/internal/auth/header.go 64/pkg/tool/linu/tmp/go-build2415659088/b165/vet.cfg conf�� g_.a H6RJmYT_A cal/bin/bash credential.usern/opt/hostedtoolcache/go/1.25.6/x64/pkg/tool/linux_amd64/compile go (dns block)
  • Triggering command: /tmp/go-build1107041789/b275/launcher.test /tmp/go-build1107041789/b275/launcher.test -test.testlogfile=/tmp/go-build1107041789/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s 5659�� 5659088/b186/_pkg_.a .cfg 64/pkg/tool/linux_amd64/vet (dns block)
  • Triggering command: /tmp/go-build1825466283/b275/launcher.test /tmp/go-build1825466283/b275/launcher.test -test.testlogfile=/tmp/go-build1825466283/b275/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go1.25.6 -c=4 -nolocalimports -importcfg /tmp/go-build1825466283/b263/importcfg -pack /tmp/go-build1825466283/b263/_testmain.go --ve�� (dns block)
• this-host-does-not-exist-12345.com
  • Triggering command: /tmp/go-build3413136910/b280/mcp.test /tmp/go-build3413136910/b280/mcp.test -test.testlogfile=/tmp/go-build3413136910/b280/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go HAdpDLDmh x_amd64/vet user.name (dns block)
  • Triggering command: /tmp/go-build1107041789/b284/mcp.test /tmp/go-build1107041789/b284/mcp.test -test.testlogfile=/tmp/go-build1107041789/b284/testlog.txt -test.paniconexit0 -test.timeout=10m0s 5659�� ache/go/1.25.6/x64/src/runtime/c-errorsas .cfg 9189de6cbc9f424a-d (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[refactor] Semantic Function Clustering Analysis - Code Organization Review</issue_title>
<issue_description>## 🎯 Analysis Overview

This automated semantic function clustering analysis examined 61 non-test Go files (391 total functions) in the MCP Gateway repository to identify refactoring opportunities through function organization patterns, semantic clustering, and code similarity detection.

Key Findings:

• ✅ Overall Organization: Good - Most packages are well-organized by feature
• ⚠️ 20 Similar Implementations: Including exact duplicates and near-duplicates (>60% similarity)
• ⚠️ 2 Files with Mixed Purposes: Some files mix validation, formatting, and I/O logic
• ℹ️ 12 Scattered Helper Functions: Helper functions spread across multiple files but logically grouped

Priority Findings:

1. Exact Duplicate: SetGatewayVersion function duplicated in 2 packages (100% identical)
2. Pattern Duplication: DIFC packages have similar set management code (Add, AddAll, Contains methods)
3. Logger Close Methods: Similar Close implementations across 3 logger types (83-88% similar)

---

Full Analysis Report

1. Exact Duplicate Functions

🔴 Critical: SetGatewayVersion (100% Identical)

Function appears in:

1. internal/config/validation_schema.go:53
2. internal/server/unified.go:36

Implementation:

func SetGatewayVersion(version string) {
    if version != "" {
        gatewayVersion = version
    }
}

Issue: Two packages maintain identical gateway version state independently. This creates:

• State synchronization risk (must call both)
• Maintenance burden (changes must be duplicated)
• Confusion about single source of truth

Recommendation:

• Create a single version module: internal/version/version.go
• Move gateway version management there
• Import from both config and server packages
• Impact: Eliminates state duplication, provides single source of truth

Estimated Effort: 1 hour (low risk refactoring)

---

2. High-Similarity Duplicates (>85%)

🟡 DIFC Set Management Pattern (87-92% similar)

Location: internal/difc/capabilities.go and internal/difc/labels.go

Both types implement nearly identical set management operations:

• Add(tag Tag) - 89.7% similar
• AddAll(tags []Tag) - 92.4% similar
• Contains(tag Tag) bool - 91.4% similar
• Count() int - 82.2% similar

Code Example (Add method):

// capabilities.go
func (c *Capabilities) Add(tag Tag) {
    c.mu.Lock()
    defer c.mu.Unlock()
    c.tags[tag] = struct{}{}
}

// labels.go
func (l *Label) Add(tag Tag) {
    l.mu.Lock()
    defer c.mu.Unlock()
    l.tags[tag] = struct{}{}
}

Analysis: Both types wrap map[Tag]struct{} with mutex protection and implement identical operations. This is a classic case for Go generics or shared implementation.

Recommendation:

• Option A: Create generic TagSet[T any] type (Go 1.18+)
• Option B: Extract shared implementation to embedded type
• Option C: Keep as-is (acceptable duplication for type-specific semantics)

Assessment: This duplication may be intentional for type safety and semantic clarity. Capabilities represents global tags while Label represents agent-specific tags. The minor duplication (4 methods) may be preferable to abstraction complexity.

Recommendation: Keep as-is - The duplication is minimal and provides clear type-specific semantics. ✅

---

🟡 Logger Close Methods (83-88% similar)

Implementations:

1. internal/logger/file_logger.go:Close()
2. internal/logger/jsonl_logger.go:Close()
3. internal/logger/markdown_logger.go:Close()

Pattern:

func (fl *FileLogger) Close() error {
    fl.mu.Lock()
    defer fl.mu.Unlock()
    return closeLogFile(fl.logFile, &fl.mu, "file")
}

func (jl *JSONLLogger) Close() error {
    jl.mu.Lock()
    defer jl.mu.Unlock()
    return closeLogFile(jl.logFile, &jl.mu, "JSONL")
}

Analysis: All three loggers delegate to shared closeLogFile helper. This is good design - the duplication is minimal (3 lines per method) and each type correctly implements its cleanup.

Recommendation: Keep as-is - This is idiomatic Go. Each type properly implements io.Closer interface. ✅

---

3. Files with Mixed Purposes

🟡 internal/config/validation_schema.go (8 functions)

Current Organization:

• Formatting functions: formatSchemaError, formatValidationErrorRecursive, formatErrorContext
• Getter functions: fetchAndFixSchema, getOrCompileSchema
• Validation functions: validateJSONSchema, validateStringPatterns

Analysis: This file mixes schema validation, error formatting, and schema fetching. The file serves a cohesive purpose (schema validation), so the mixed categories are acceptable.

Recommendation: **Acceptable...

Custom agent used: agentic-workflows
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• Fixes [refactor] Semantic Function Clustering Analysis - Code Organization Review #671

---

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[Copilot]

Pull request overview

This PR consolidates three duplicate implementations of version management (SetGatewayVersion in config and server packages, plus SetClientGatewayVersion in the mcp package) into a single source of truth. A new internal/version package provides centralized version state management with Set() and Get() functions.

Changes:

• Created internal/version package with Set(v string) and Get() string functions
• Removed duplicate version management code from config, server, and mcp packages
• Updated all call sites to use version.Get() for reading the version
• Renamed cmd.version to cmd.cliVersion to avoid naming collision with the new version package

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/version/version.go	New package providing centralized version state with Set() and Get() functions
internal/version/version_test.go	Comprehensive tests for the new version package covering Set(), Get(), and empty string handling
internal/server/unified.go	Removed duplicate SetGatewayVersion() function and gatewayVersion variable
internal/server/server.go	Updated to import and use version.Get() for health endpoint
internal/server/health.go	Updated to import and use version.Get() for health response
internal/mcp/connection.go	Removed SetClientGatewayVersion() and updated MCP client to use version.Get()
internal/config/validation_schema.go	Removed duplicate SetGatewayVersion() and updated error messages to use version.Get()
internal/config/validation_schema_test.go	Updated test to use version.Set() instead of config.SetGatewayVersion()
internal/cmd/root.go	Renamed version to cliVersion, updated SetVersion() to call version.Set(), and updated imports

---

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[Copilot]

The original mcp.SetClientGatewayVersion implementation used strings.TrimSpace(version) != "" to check for empty strings, while config.SetGatewayVersion and server.SetGatewayVersion used version != "". The new implementation follows the config/server pattern, which means it will accept whitespace-only strings as valid versions (unlike the original mcp implementation). While unlikely to cause issues since the version is set from properly formatted strings in main.go, this is a subtle behavior change. Consider using strings.TrimSpace(v) != "" to maintain the most restrictive behavior from all three original implementations.

[Copilot]

The comment mentions "in SetVersion" but the function is actually named "Set". This should be corrected to "in Set()" for accuracy.

Suggested change

	// (in SetVersion) before any concurrent access, and read-only thereafter.
	// (in Set()) before any concurrent access, and read-only thereafter.