Extract duplicate HTTP connection error detection into helper function

[Copilot]

Duplicate string matching logic for detecting connection errors (connection refused, no such host, network is unreachable) existed in both initializeHTTPSession and sendHTTPRequest.

Changes

• Added isConnectionError() helper: Centralizes connection error detection logic
• Updated two call sites: Both methods now use the helper instead of inline checks

Before

if strings.Contains(err.Error(), "connection refused") ||
    strings.Contains(err.Error(), "no such host") ||
    strings.Contains(err.Error(), "network is unreachable") {
    return nil, fmt.Errorf("cannot connect to HTTP backend at %s: %w", c.httpURL, err)
}

After

if isConnectionError(err) {
    return nil, fmt.Errorf("cannot connect to HTTP backend at %s: %w", c.httpURL, err)
}

Adding new error types now requires updating a single location.

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-build373359847/b271/launcher.test /tmp/go-build373359847/b271/launcher.test -test.testlogfile=/tmp/go-build373359847/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go path/match.go x_amd64/vet (dns block)
• invalid-host-that-does-not-exist-12345.com
  • Triggering command: /tmp/go-build373359847/b259/config.test /tmp/go-build373359847/b259/config.test -test.testlogfile=/tmp/go-build373359847/b259/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true --global go 64/pkg/tool/linux_amd64/compile (dns block)
• nonexistent.local
  • Triggering command: /tmp/go-build373359847/b271/launcher.test /tmp/go-build373359847/b271/launcher.test -test.testlogfile=/tmp/go-build373359847/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go path/match.go x_amd64/vet (dns block)
• slow.example.com
  • Triggering command: /tmp/go-build373359847/b271/launcher.test /tmp/go-build373359847/b271/launcher.test -test.testlogfile=/tmp/go-build373359847/b271/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go path/match.go x_amd64/vet (dns block)
• this-host-does-not-exist-12345.com
  • Triggering command: /tmp/go-build373359847/b280/mcp.test /tmp/go-build373359847/b280/mcp.test -test.testlogfile=/tmp/go-build373359847/b280/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true go --global /home/REDACTED/.ca-o user.name (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

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This section details on the original issue you should resolve

<issue_title>[duplicate-code] Duplicate Code Pattern: HTTP Connection Error Checking</issue_title>
<issue_description># 🔍 Duplicate Code Pattern: HTTP Connection Error Checking

Part of duplicate code analysis: #739

Summary

Duplicated HTTP connection error detection logic in internal/mcp/connection.go. The same error checking pattern (connection refused, no such host, network unreachable) appears in two methods with identical string matching logic.

Duplication Details

Pattern: HTTP Connection Error Detection

• Severity: Medium

• Occurrences: 2 instances in the same file

• Locations:

  • internal/mcp/connection.go (lines 587-590) - in initializeHTTPSession
  • internal/mcp/connection.go (lines 701-704) - in sendHTTPRequest

• Code Sample:

  // Duplicated in initializeHTTPSession (lines 587-590)
  if strings.Contains(err.Error(), "connection refused") ||
      strings.Contains(err.Error(), "no such host") ||
      strings.Contains(err.Error(), "network is unreachable") {
      return "", fmt.Errorf("cannot connect to HTTP backend at %s: %w", c.httpURL, err)
  }
  
  // Duplicated in sendHTTPRequest (lines 701-704)
  if strings.Contains(err.Error(), "connection refused") ||
      strings.Contains(err.Error(), "no such host") ||
      strings.Contains(err.Error(), "network is unreachable") {
      return nil, fmt.Errorf("cannot connect to HTTP backend at %s: %w", c.httpURL, err)
  }

Impact Analysis

• Maintainability: Adding new error types requires updating multiple locations
• Bug Risk: Inconsistent error handling if one location is updated but not the other
• Code Bloat: ~8 lines of duplicated logic

Refactoring Recommendations

1. Extract to Helper Function

   • Extract to: internal/mcp/connection.go (add helper method)
   • Estimated effort: 15 minutes
   • Benefits: Single source of truth for connection error detection

   // isConnectionError checks if an error indicates a connection failure
   func isConnectionError(err error) bool {
       if err == nil {
           return false
       }
       errStr := err.Error()
       return strings.Contains(errStr, "connection refused") ||
              strings.Contains(errStr, "no such host") ||
              strings.Contains(errStr, "network is unreachable")
   }
   
   // Usage in both methods:
   if isConnectionError(err) {
       return nil, fmt.Errorf("cannot connect to HTTP backend at %s: %w", c.httpURL, err)
   }

Implementation Checklist

• Review duplication findings
• Create isConnectionError helper function in internal/mcp/connection.go
• Replace both duplicated checks with helper calls
• Run make test-all to verify no functionality broken
• Consider adding tests for the new helper function
• Run make agent-finished before completion

Parent Issue

See parent analysis report: #739
Related to #739

AI generated by Duplicate Code Detector

• expires on Feb 13, 2026, 3:07 AM UTC

Comments on the Issue (you are @copilot in this section)

Custom agent used: agentic-workflows
GitHub Agentic Workflows (gh-aw) - Create, debug, and upgrade AI-powered workflows with intelligent prompt routing

• Fixes [duplicate-code] Duplicate Code Pattern: HTTP Connection Error Checking #740

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[Copilot]

Pull request overview

This PR reduces duplication in the MCP HTTP connection logic by extracting repeated “connection error” string-matching checks into a single helper, improving maintainability and consistency in error handling.

Changes:

• Added an isConnectionError(err error) bool helper in internal/mcp/connection.go.
• Updated initializeHTTPSession and sendHTTPRequest to use the helper.
• Added unit tests covering isConnectionError behavior.

Reviewed changes

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

File	Description
internal/mcp/connection.go	Introduces isConnectionError and replaces duplicated inline checks at two HTTP call sites.
internal/mcp/connection_test.go	Adds table-driven tests for the new helper.

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