Things I Hate - Go Edition

June 3, 2020

Cyclical dependencies

Go disallows circular dependencies between packages.

In Java this is allowed:

package b;

import a.A;

public class B {
    public static void main(String[] args) {
	System.out.println("A.main");
	A.doA();
    }
    
    public static void doB() {
	System.out.println("B.doB");
    }
}

---
package a;

import b.B;

public class A {
    public static void main(String[] args) {
	System.out.println("A.main");
	B.doB();
    }

    public static void doA() {
	System.out.println("A.doA");
    }
}

Similar code is forbidden in Go. If you want to have test utilities, you often run into circular dependencies, leading to practices like https://golang.org/src/net/http/main_test.go, where a file packaged as foo_test lives in the same directory as files named foo.

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package http_test

import (
	"fmt"
	"io/ioutil"
...

What an ugly hack.