From 48f5a9a18c1ffc33a9be31d8f26b384c267f336f Mon Sep 17 00:00:00 2001
From: Juan Font Alonso <juanfontalonso@gmail.com>
Date: Sun, 10 Oct 2021 23:55:03 +0200
Subject: [PATCH] Fix error 500 when deleting shared node (fixes #133)

---
 machine.go | 11 +++++++++++
 sharing.go | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/machine.go b/machine.go
index ecea378f..2fa4d9e0 100644
--- a/machine.go
+++ b/machine.go
@@ -179,6 +179,11 @@ func (h *Headscale) UpdateMachine(m *Machine) error {
 
 // DeleteMachine softs deletes a Machine from the database
 func (h *Headscale) DeleteMachine(m *Machine) error {
+	err := h.RemoveSharedMachineFromAllNamespaces(m)
+	if err != nil && err != errorMachineNotShared {
+		return err
+	}
+
 	m.Registered = false
 	namespaceID := m.NamespaceID
 	h.db.Save(&m) // we mark it as unregistered, just in case
@@ -191,10 +196,16 @@ func (h *Headscale) DeleteMachine(m *Machine) error {
 
 // HardDeleteMachine hard deletes a Machine from the database
 func (h *Headscale) HardDeleteMachine(m *Machine) error {
+	err := h.RemoveSharedMachineFromAllNamespaces(m)
+	if err != nil && err != errorMachineNotShared {
+		return err
+	}
+
 	namespaceID := m.NamespaceID
 	if err := h.db.Unscoped().Delete(&m).Error; err != nil {
 		return err
 	}
+
 	return h.RequestMapUpdates(namespaceID)
 }
 
diff --git a/sharing.go b/sharing.go
index 93c299c7..83ce5260 100644
--- a/sharing.go
+++ b/sharing.go
@@ -4,6 +4,7 @@ import "gorm.io/gorm"
 
 const errorSameNamespace = Error("Destination namespace same as origin")
 const errorMachineAlreadyShared = Error("Node already shared to this namespace")
+const errorMachineNotShared = Error("Machine not shared to this namespace")
 
 // SharedMachine is a join table to support sharing nodes between namespaces
 type SharedMachine struct {
@@ -35,3 +36,13 @@ func (h *Headscale) AddSharedMachineToNamespace(m *Machine, ns *Namespace) error
 
 	return nil
 }
+
+// RemoveSharedMachineFromAllNamespaces removes a machine as a shared node from all namespaces
+func (h *Headscale) RemoveSharedMachineFromAllNamespaces(m *Machine) error {
+	sharedMachine := SharedMachine{}
+	if result := h.db.Where("machine_id = ?", m.ID).Unscoped().Delete(&sharedMachine); result.Error != nil {
+		return result.Error
+	}
+
+	return nil
+}