fix: check if resp is nil on error for initialize methods

pottekkat · pottekkat · commit 95201f2130c5 · 2025-07-16T22:08:37.000+05:30
diff --git a/client/transport/streamable_http.go b/client/transport/streamable_http.go
@@ -252,7 +252,12 @@ func (c *StreamableHTTP) SendRequest(
 			return nil, fmt.Errorf("failed to send request: %w", err)
 		}
 	}
-	defer resp.Body.Close()
+	// When sendHTTP fails and resp is nil but method is mcp.MethodInitialize
+	// defer resp.Body.Close() fails with nil pointer dereference.
+	// TODO: Restructure this fallthrough logic properly.
+	if resp != nil {
+		defer resp.Body.Close()
+	}
 
 	// Check if we got an error response
 	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {

Original file line number	Diff line number	Diff line change
`@@ -252,7 +252,12 @@ func (c *StreamableHTTP) SendRequest(`
`252`	`252`	`return nil, fmt.Errorf("failed to send request: %w", err)`
`253`	`253`	`}`
`254`	`254`	`}`
`255`		`- defer resp.Body.Close()`
	`255`	`+ // When sendHTTP fails and resp is nil but method is mcp.MethodInitialize`
	`256`	`+ // defer resp.Body.Close() fails with nil pointer dereference.`
	`257`	`+ // TODO: Restructure this fallthrough logic properly.`
	`258`	`+ if resp != nil {`
	`259`	`+ defer resp.Body.Close()`
	`260`	`+ }`
`256`	`261`
`257`	`262`	`// Check if we got an error response`
`258`	`263`	`if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {`