[duplicate-code] Duplicate Code Pattern: Session Reconnect Telemetry in connection.go

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Part of duplicate code analysis: #3631

Summary

reconnectPlainJSON() and reconnectSDKTransport() in internal/mcp/connection.go contain three identical logger.Log* call sites — one at the start (warn), one on failure (error), one on success (info). This is exact copy-paste duplication across two sibling functions that follow the same reconnect lifecycle.

Duplication Details

Pattern: Identical session reconnect lifecycle log messages

• Severity: High
• Occurrences: 3 unique log lines × 2 functions = 6 duplicated call sites
• Locations:
  • internal/mcp/connection.go — reconnectPlainJSON() lines 312, 316, 322
  • internal/mcp/connection.go — reconnectSDKTransport() lines 333, 368, 376

Code Sample — reconnectPlainJSON (lines 307–325):

func (c *Connection) reconnectPlainJSON() error {
    c.sessionMu.Lock()
    defer c.sessionMu.Unlock()

    logConn.Printf("Session expired, reconnecting plain JSON-RPC for serverID=%s", c.serverID)
    logger.LogWarn("backend", "MCP session expired for %s, attempting to reconnect...", c.serverID)  // ← duplicate

    sessionID, err := c.initializeHTTPSession()
    if err != nil {
        logger.LogError("backend", "Session reconnect failed for %s: %v", c.serverID, err)           // ← duplicate
        return fmt.Errorf("session reconnect failed: %w", err)
    }
    ...
    logger.LogInfo("backend", "Session successfully reconnected for %s", c.serverID)                 // ← duplicate
    return nil
}

Code Sample — reconnectSDKTransport (lines 328–377):

func (c *Connection) reconnectSDKTransport() error {
    c.sessionMu.Lock()
    defer c.sessionMu.Unlock()

    logConn.Printf("Session expired, reconnecting SDK transport for serverID=%s, type=%s", c.serverID, c.httpTransportType)
    logger.LogWarn("backend", "MCP session expired for %s, attempting to reconnect...", c.serverID)  // ← identical

    ...
    session, err := client.Connect(connectCtx, transport, nil)
    if err != nil {
        logger.LogError("backend", "Session reconnect failed for %s: %v", c.serverID, err)           // ← identical
        return fmt.Errorf("session reconnect failed: %w", err)
    }
    ...
    logger.LogInfo("backend", "Session successfully reconnected for %s", c.serverID)                 // ← identical
    return nil
}

Impact Analysis

• Maintainability: If the log format for reconnect events ever needs to change (e.g., adding a field), it must be updated in two separate functions. One is easily missed.
• Bug Risk: Divergence between the two copies has already been shown to be feasible — the logConn.Printf opening line already differs slightly between the two functions, demonstrating that the copies can drift.
• Code Bloat: Minor — 3 extra lines.

Refactoring Recommendations

1. Extract logReconnectStart / logReconnectResult helpers (preferred)

   • Add two small private functions to connection.go:

     func (c *Connection) logReconnectStart() {
         logger.LogWarn("backend", "MCP session expired for %s, attempting to reconnect...", c.serverID)
     }
     func (c *Connection) logReconnectResult(err error) {
         if err != nil {
             logger.LogError("backend", "Session reconnect failed for %s: %v", c.serverID, err)
         } else {
             logger.LogInfo("backend", "Session successfully reconnected for %s", c.serverID)
         }
     }

   • Replace the three duplicate call sites in each function with c.logReconnectStart() and c.logReconnectResult(err).
   • Estimated effort: 30 minutes
   • Benefits: single source of truth for reconnect event log messages; easier to add structured fields later (e.g., reconnect attempt count)

2. Alternatively: introduce a generic withReconnectLogging(serverID string, reconnectFn func() error) error wrapper, but this adds more indirection than is warranted for three log lines.

Implementation Checklist

• Add logReconnectStart() and logReconnectResult(err error) helpers to connection.go
• Replace duplicate log calls in reconnectPlainJSON
• Replace duplicate log calls in reconnectSDKTransport
• Run make test to verify no regressions
• Run make lint to verify formatting

Parent Issue

See parent analysis report: #3631
Related to #3631

Generated by Duplicate Code Detector · ● 1.3M · ◷

• expires on Apr 19, 2026, 6:07 AM UTC