fix(resources): improve custom_field attribute handling to avoid permanent diffs

netbox/custom_fields.go

@@ -1,6 +1,8 @@
 package netbox
 
 import (
+	"context"
+
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
 
@@ -9,17 +11,77 @@ const customFieldsKey = "custom_fields"
 var customFieldsSchema = &schema.Schema{
 	Type:     schema.TypeMap,
 	Optional: true,
+	Computed: true,
 	Default:  nil,
 	Elem: &schema.Schema{
 		Type:    schema.TypeString,
 		Default: nil,
 	},
 }
 
-func getCustomFields(cf interface{}) map[string]interface{} {
-	cfm, ok := cf.(map[string]interface{})
-	if !ok || len(cfm) == 0 {
-		return nil
+var customFieldsSchemaRead = &schema.Schema{
+	Type:     schema.TypeMap,
+	Computed: true,
+	Elem: &schema.Schema{
+		Type: schema.TypeString,
+	},
+}
+
+func normalizeCustomFields(cfm map[string]interface{}) map[string]interface{} {
+	newcfm := make(map[string]interface{})
+
+	for k, v := range cfm {
+		if v != nil && v != "" {
+			newcfm[k] = v
+		}
+	}
+
+	return newcfm
+}
+
+func mergeCustomFields(oldcfm, newcfm map[string]interface{}) map[string]interface{} {
+	if newcfm == nil {
+		newcfm = make(map[string]interface{})
+	}
+
+	for k, v := range newcfm {
+		if v == nil {
+			newcfm[k] = ""
+		}
+	}
+
+	for k := range oldcfm {
+		if _, ok := newcfm[k]; !ok {
+			newcfm[k] = ""
+		}
+	}
+
+	return newcfm
+}
+
+func customFieldsDiff(ctx context.Context, d *schema.ResourceDiff, meta interface{}) error {
+	cfg := d.GetRawConfig().GetAttr(customFieldsKey)
+	cfm, ok := d.Get(customFieldsKey).(map[string]interface{})
+
+	if cfg.IsNull() || !ok {
+		d.SetNew(customFieldsKey, nil)
+	} else {
+		newcfm := normalizeCustomFields(cfm)
+		d.SetNew(customFieldsKey, newcfm)
 	}
-	return cfm
+
+	return nil
+}
+
+func computeCustomFieldsAttr(cf interface{}) map[string]interface{} {
+	cfm, _ := cf.(map[string]interface{})
+	return normalizeCustomFields(cfm)
+}
+
+func computeCustomFieldsModel(d *schema.ResourceData) interface{} {
+	oldcf, newcf := d.GetChange(customFieldsKey)
+
+	oldcfm, _ := oldcf.(map[string]interface{})
+	newcfm, _ := newcf.(map[string]interface{})
+	return mergeCustomFields(oldcfm, newcfm)
 }

netbox/custom_fields_test.go

@@ -0,0 +1,185 @@
+package netbox
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCustomFields_normalize(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    map[string]interface{}
+		expected map[string]interface{}
+	}{
+		{
+			name:     "MapNil",
+			input:    nil,
+			expected: map[string]interface{}{},
+		},
+		{
+			name:     "MapEmpty",
+			input:    map[string]interface{}{},
+			expected: map[string]interface{}{},
+		},
+		{
+			name: "MapFull",
+			input: map[string]interface{}{
+				"key1": "value1",
+				"key2": "value2",
+			},
+			expected: map[string]interface{}{
+				"key1": "value1",
+				"key2": "value2",
+			},
+		},
+		{
+			name: "MapMixed",
+			input: map[string]interface{}{
+				"key1": "value1",
+				"key2": "",
+				"key3": nil,
+			},
+			expected: map[string]interface{}{
+				"key1": "value1",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := normalizeCustomFields(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestCustomFields_merge(t *testing.T) {
+	tests := []struct {
+		name     string
+		state    map[string]interface{}
+		input    map[string]interface{}
+		expected map[string]interface{}
+	}{
+		{
+			name:     "MapNilBoth",
+			state:    nil,
+			input:    nil,
+			expected: map[string]interface{}{},
+		},
+		{
+			name:     "MapNilNew",
+			state:    map[string]interface{}{},
+			input:    nil,
+			expected: map[string]interface{}{},
+		},
+		{
+			name:     "MapNilOld",
+			state:    nil,
+			input:    map[string]interface{}{},
+			expected: map[string]interface{}{},
+		},
+		{
+			name: "MapUnsetWithMissing",
+			state: map[string]interface{}{
+				"key1": "value1",
+			},
+			input: map[string]interface{}{},
+			expected: map[string]interface{}{
+				"key1": "",
+			},
+		},
+		{
+			name: "MapUnsetWithNil",
+			state: map[string]interface{}{
+				"key1": "value1",
+			},
+			input: map[string]interface{}{
+				"key1": nil,
+			},
+			expected: map[string]interface{}{
+				"key1": "",
+			},
+		},
+		{
+			name: "MapUnsetWithEmpty",
+			state: map[string]interface{}{
+				"key1": "value1",
+			},
+			input: map[string]interface{}{},
+			expected: map[string]interface{}{
+				"key1": "",
+			},
+		},
+		{
+			name:  "MapUnsetWithNilNotSet",
+			state: map[string]interface{}{},
+			input: map[string]interface{}{
+				"key1": nil,
+			},
+			expected: map[string]interface{}{
+				"key1": "",
+			},
+		},
+		{
+			name:  "MapUnsetWithEmptyNotSet",
+			state: map[string]interface{}{},
+			input: map[string]interface{}{
+				"key1": "",
+			},
+			expected: map[string]interface{}{
+				"key1": "",
+			},
+		},
+		{
+			name:  "MapSetNew",
+			state: map[string]interface{}{},
+			input: map[string]interface{}{
+				"key1": "test",
+			},
+			expected: map[string]interface{}{
+				"key1": "test",
+			},
+		},
+		{
+			name: "MapSetExisting",
+			state: map[string]interface{}{
+				"key1": " test",
+			},
+			input: map[string]interface{}{
+				"key1": "testnew",
+			},
+			expected: map[string]interface{}{
+				"key1": "testnew",
+			},
+		},
+		{
+			name: "MapMixed",
+			state: map[string]interface{}{
+				"key1": "value1",
+				"key2": "value2",
+				"key3": "",
+				"key4": nil,
+			},
+			input: map[string]interface{}{
+				"key1":   "valuenew1",
+				"key2":   nil,
+				"keynew": "valuenew2",
+			},
+			expected: map[string]interface{}{
+				"key1":   "valuenew1",
+				"key2":   "",
+				"key3":   "",
+				"key4":   "",
+				"keynew": "valuenew2",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := mergeCustomFields(tt.state, tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}

netbox/data_source_netbox_cluster.go

@@ -53,11 +53,8 @@ func dataSourceNetboxCluster() *schema.Resource {
 				Computed: true,
 				Optional: true,
 			},
-			"custom_fields": {
-				Type:     schema.TypeMap,
-				Computed: true,
-			},
-			tagsKey: tagsSchemaRead,
+			customFieldsKey: customFieldsSchemaRead,
+			tagsKey:         tagsSchemaRead,
 		},
 	}
 }
@@ -116,10 +113,10 @@ func dataSourceNetboxClusterRead(d *schema.ResourceData, m interface{}) error {
 	} else {
 		d.Set("site_id", nil)
 	}
-	if result.CustomFields != nil {
-		d.Set("custom_fields", result.CustomFields)
-	}
+
+	d.Set(customFieldsKey, result.CustomFields)
 
 	d.Set(tagsKey, getTagListFromNestedTagList(result.Tags))
+
 	return nil
 }

netbox/data_source_netbox_prefix.go

@@ -27,7 +27,6 @@ func dataSourceNetboxPrefix() *schema.Resource {
 				ValidateFunc:  validation.IsCIDR,
 				AtLeastOneOf:  []string{"description", "family", "prefix", "vlan_vid", "vrf_id", "vlan_id", "tenant_id", "site_id", "role_id", "cidr", "tag", "status"},
 			},
-			customFieldsKey: customFieldsSchema,
 			"description": {
 				Type:         schema.TypeString,
 				Optional:     true,
@@ -100,7 +99,8 @@ for more information on available lookup expressions.`,
 				Optional:     true,
 				AtLeastOneOf: []string{"description", "family", "prefix", "vlan_vid", "vrf_id", "vlan_id", "tenant_id", "site_id", "role_id", "cidr", "tag", "status"},
 			},
-			"tags": tagsSchemaRead,
+			customFieldsKey: customFieldsSchemaRead,
+			tagsKey:         tagsSchemaRead,
 		},
 	}
 }
@@ -189,12 +189,11 @@ func dataSourceNetboxPrefixRead(d *schema.ResourceData, m interface{}) error {
 	d.Set("status", result.Status.Value)
 	d.Set("description", result.Description)
 	d.Set("family", int(*result.Family.Value))
-	d.Set("tags", getTagListFromNestedTagList(result.Tags))
 
-	cf := getCustomFields(result.CustomFields)
-	if cf != nil {
-		d.Set(customFieldsKey, cf)
-	}
+	d.Set(customFieldsKey, result.CustomFields)
+
+	d.Set(tagsKey, getTagListFromNestedTagList(result.Tags))
+
 	if result.Role != nil {
 		d.Set("role_id", result.Role.ID)
 	}

netbox/data_source_netbox_racks.go

@@ -67,7 +67,6 @@ func dataSourceNetboxRacks() *schema.Resource {
 							Type:     schema.TypeInt,
 							Computed: true,
 						},
-						tagsKey: tagsSchemaRead,
 						"tenant_id": {
 							Type:     schema.TypeInt,
 							Computed: true,
@@ -136,10 +135,8 @@ func dataSourceNetboxRacks() *schema.Resource {
 							Type:     schema.TypeString,
 							Computed: true,
 						},
-						"custom_fields": {
-							Type:     schema.TypeMap,
-							Computed: true,
-						},
+						customFieldsKey: customFieldsSchemaRead,
+						tagsKey:         tagsSchemaRead,
 					},
 				},
 			},
@@ -246,7 +243,6 @@ func dataSourceNetboxRacksRead(d *schema.ResourceData, m interface{}) error {
 			mapping["width"] = v.Width.Value
 		}
 		mapping["u_height"] = v.UHeight
-		mapping["tags"] = getTagListFromNestedTagList(v.Tags)
 		if v.Tenant != nil {
 			mapping["tenant_id"] = v.Tenant.ID
 		}
@@ -273,7 +269,10 @@ func dataSourceNetboxRacksRead(d *schema.ResourceData, m interface{}) error {
 		mapping["mounting_depth"] = v.MountingDepth
 		mapping["description"] = v.Description
 		mapping["comments"] = v.Comments
-		mapping["custom_fields"] = getCustomFields(v.CustomFields)
+
+		mapping[customFieldsKey] = v.CustomFields
+
+		mapping[tagsKey] = getTagListFromNestedTagList(v.Tags)
 
 		s = append(s, mapping)
 	}