From 1598bb20431e5b96e43880c65b2212782a2b3537 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lars=20Tobias=20Skjong-B=C3=B8rsting?=
 <larstobi@relatime.no>
Date: Tue, 2 Aug 2022 19:52:48 +0200
Subject: [PATCH] Fix nil pointer dereference accessing CPUS String() (#11)

* fixes #10

* Also fixes changes when an optional attribute is omitted
---
 internal/provider/resource_instance.go |  9 +++++-
 internal/provider/utils.go             | 45 +++++++++++++++-----------
 2 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/internal/provider/resource_instance.go b/internal/provider/resource_instance.go
index 808970b..6b48c7f 100644
--- a/internal/provider/resource_instance.go
+++ b/internal/provider/resource_instance.go
@@ -119,10 +119,17 @@ func (r instanceResource) Create(ctx context.Context, req tfsdk.CreateResourceRe
         "name": plan.Name.String(),
     })
 
+    var cpus string
+    if plan.CPUS.Null {
+        cpus = ""
+    } else {
+        cpus = plan.CPUS.Value.String()
+    }
+
     _, err := multipass.LaunchV2(&multipass.LaunchReqV2{
         Name:          plan.Name.Value,
         Image:         plan.Image.Value,
-        CPUS:          plan.CPUS.Value.String(),
+        CPUS:          cpus,
         Memory:        plan.Memory.Value,
         Disk:          plan.Disk.Value,
         CloudInitFile: plan.CloudInitFile.Value,
diff --git a/internal/provider/utils.go b/internal/provider/utils.go
index e5a790f..64fff20 100644
--- a/internal/provider/utils.go
+++ b/internal/provider/utils.go
@@ -18,32 +18,39 @@ func QueryInstance(state Instance) (*Instance, error) {
 	}
 
 	// Check CPUS
-	cpus := new(big.Float)
-	cpus.SetString(out.CPUS)
-
-	// Check Memory
-	if state.Memory.Null {
-		state.Memory = types.String{Value: "0MiB"}
+	current_cpus := state.CPUS
+	// If CPUS is not specified, then ignore changes
+	if !state.CPUS.Null {
+		cpus := new(big.Float)
+		cpus.SetString(out.CPUS)
+		if cpus != state.CPUS.Value {
+			current_cpus = types.Number{Value: cpus}
+		}
 	}
 
+	// Check Memory
 	current_memory := state.Memory
-	if equal, err := CompareDataSizes(out.Memory, state.Memory.Value); err != nil {
-		return nil, errors.New("Error comparing memory size: " + err.Error())
-	} else {
-		if !*equal {
-			current_memory = types.String{Value: RemoveZeroDecimalAndSpaces(out.Memory)}
+	// If Memory is not specified, then ignore changes
+	if !state.Memory.Null {
+		if equal, err := CompareDataSizes(out.Memory, state.Memory.Value); err != nil {
+			return nil, errors.New("Error comparing memory size: " + err.Error())
+		} else {
+			if !*equal {
+				current_memory = types.String{Value: RemoveZeroDecimalAndSpaces(out.Memory)}
+			}
 		}
 	}
 
 	// Check Disk
-	var current_disk types.String
-	if equal, err := CompareDataSizes(out.Disk, state.Disk.Value); err != nil {
-		return nil, errors.New("Error comparing disk size: " + err.Error())
-	} else {
-		if *equal {
-			current_disk = state.Disk
+	current_disk := state.Disk
+	// If Disk is not specified, then ignore changes
+	if !state.Disk.Null {
+		if equal, err := CompareDataSizes(out.Disk, state.Disk.Value); err != nil {
+			return nil, errors.New("Error comparing disk size: " + err.Error())
 		} else {
-			current_disk = types.String{Value: RemoveZeroDecimalAndSpaces(out.Disk)}
+			if !*equal {
+				current_disk = types.String{Value: RemoveZeroDecimalAndSpaces(out.Disk)}
+			}
 		}
 	}
 
@@ -51,7 +58,7 @@ func QueryInstance(state Instance) (*Instance, error) {
 	var result = Instance{
 		Name:          state.Name,
 		Image:         state.Image,
-		CPUS:          types.Number{Value: cpus},
+		CPUS:          current_cpus,
 		Memory:        current_memory,
 		Disk:          current_disk,
 		CloudInitFile: state.CloudInitFile,