style: Addressed PR comments

api/rest/client.go

@@ -98,7 +98,7 @@ func (c *Client) DoRequest(req *http.Request, resp interface{}) (int, error) {
 		}{}
 		body, err := io.ReadAll(httpResp.Body)
 		if err != nil {
-			return httpResp.StatusCode, err
+			return 0, err
 		}
 		err = json.Unmarshal(body, &httpError)
 		if err != nil {

config/api_client.go

@@ -2,16 +2,15 @@ package config
 
 import (
 	"fmt"
+	"net/http"
 	"net/url"
 
 	"github.com/CircleCI-Public/circleci-cli/api/graphql"
 	"github.com/CircleCI-Public/circleci-cli/api/rest"
 	"github.com/CircleCI-Public/circleci-cli/settings"
 )
 
-var (
-	compilePath = "compile-config-with-defaults"
-)
+const compilePath = "compile-config-with-defaults"
 
 type apiClientVersion string
 
@@ -38,17 +37,25 @@ func newAPIClient(config *settings.Config) (APIClient, error) {
 	}
 }
 
+// detectAPIClientVersion returns the highest available version of the config API.
+//
+// To do that it tries to request the `compilePath` API route.
+// If the route returns a 404, this means the route does not exist on the requested host and the function returns
+// `v1_string` indicating that the deprecated GraphQL endpoint should be used instead.
+// Else if the route returns any other status, this means it is available for request and the function returns
+// `v2_string` indicating that the route can be used
 func detectAPIClientVersion(restClient *rest.Client) (apiClientVersion, error) {
 	req, err := restClient.NewRequest("POST", &url.URL{Path: compilePath}, nil)
 	if err != nil {
 		return "", err
 	}
 
-	statusCode, err := restClient.DoRequest(req, nil)
-	if _, ok := err.(*rest.HTTPError); !ok {
+	_, err = restClient.DoRequest(req, nil)
+	httpErr, ok := err.(*rest.HTTPError)
+	if !ok {
 		return "", err
 	}
-	if statusCode == 404 {
+	if httpErr.Code == http.StatusNotFound {
 		return v1_string, nil
 	}
 	return v2_string, nil