fix: terraform-plugin-sdk zeros *int fields (#123)

Author: mtojek

Diff for: docs/data-sources/parameter.md

@@ -63,4 +63,9 @@ Optional:
 - `monotonic` (String) Number monotonicity, either increasing or decreasing.
 - `regex` (String) A regex for the input parameter to match against.
 
+Read-Only:
+
+- `max_disabled` (Boolean) Helper field to check if max is present
+- `min_disabled` (Boolean) Helper field to check if min is present
+
 

Diff for: provider/decode_test.go

@@ -3,10 +3,11 @@ package provider_test
 import (
 	"testing"
 
-	"github.com/coder/terraform-provider-coder/provider"
 	"github.com/mitchellh/mapstructure"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/coder/terraform-provider-coder/provider"
 )
 
 func TestDecode(t *testing.T) {
@@ -23,11 +24,12 @@ func TestDecode(t *testing.T) {
 		"display_name":         displayName,
 		"legacy_variable":      legacyVariable,
 		"legacy_variable_name": legacyVariableName,
-		"min":                  nil,
 		"validation": []map[string]interface{}{
 			{
-				"min": nil,
-				"max": 5,
+				"min":          nil,
+				"min_disabled": false,
+				"max":          5,
+				"max_disabled": true,
 			},
 		},
 	}
@@ -38,6 +40,8 @@ func TestDecode(t *testing.T) {
 	assert.Equal(t, displayName, param.DisplayName)
 	assert.Equal(t, legacyVariable, param.LegacyVariable)
 	assert.Equal(t, legacyVariableName, param.LegacyVariableName)
-	assert.Equal(t, (*int)(nil), param.Validation[0].Min)
-	assert.Equal(t, 5, *param.Validation[0].Max)
+	assert.Equal(t, 5, param.Validation[0].Max)
+	assert.True(t, param.Validation[0].MaxDisabled)
+	assert.Equal(t, 0, param.Validation[0].Min)
+	assert.False(t, param.Validation[0].MinDisabled)
 }

Diff for: provider/parameter.go

@@ -28,8 +28,11 @@ type Option struct {
 }
 
 type Validation struct {
-	Min       *int
-	Max       *int
+	Min         int
+	MinDisabled bool `mapstructure:"min_disabled"`
+	Max         int
+	MaxDisabled bool `mapstructure:"max_disabled"`
+
 	Monotonic string
 
 	Regex string
@@ -288,11 +291,21 @@ func parameterDataSource() *schema.Resource {
 							Optional:    true,
 							Description: "The minimum of a number parameter.",
 						},
+						"min_disabled": {
+							Type:        schema.TypeBool,
+							Computed:    true,
+							Description: "Helper field to check if min is present",
+						},
 						"max": {
 							Type:        schema.TypeInt,
 							Optional:    true,
 							Description: "The maximum of a number parameter.",
 						},
+						"max_disabled": {
+							Type:        schema.TypeBool,
+							Computed:    true,
+							Description: "Helper field to check if max is present",
+						},
 						"monotonic": {
 							Type:        schema.TypeString,
 							Optional:    true,
@@ -363,13 +376,8 @@ func fixValidationResourceData(rawConfig cty.Value, validation interface{}) (int
 		return nil, xerrors.New("validation rule should be a map")
 	}
 
-	// Fix the resource data
-	if rawValidationRule["min"].IsNull() {
-		validationRule["min"] = nil
-	}
-	if rawValidationRule["max"].IsNull() {
-		validationRule["max"] = nil
-	}
+	validationRule["min_disabled"] = rawValidationRule["min"].IsNull()
+	validationRule["max_disabled"] = rawValidationRule["max"].IsNull()
 	return vArr, nil
 }
 
@@ -401,10 +409,10 @@ func valueIsType(typ, value string) diag.Diagnostics {
 
 func (v *Validation) Valid(typ, value string) error {
 	if typ != "number" {
-		if v.Min != nil {
+		if !v.MinDisabled {
 			return fmt.Errorf("a min cannot be specified for a %s type", typ)
 		}
-		if v.Max != nil {
+		if !v.MaxDisabled {
 			return fmt.Errorf("a max cannot be specified for a %s type", typ)
 		}
 	}
@@ -437,11 +445,11 @@ func (v *Validation) Valid(typ, value string) error {
 		if err != nil {
 			return fmt.Errorf("value %q is not a number", value)
 		}
-		if v.Min != nil && num < *v.Min {
-			return fmt.Errorf("value %d is less than the minimum %d", num, *v.Min)
+		if !v.MinDisabled && num < v.Min {
+			return fmt.Errorf("value %d is less than the minimum %d", num, v.Min)
 		}
-		if v.Max != nil && num > *v.Max {
-			return fmt.Errorf("value %d is more than the maximum %d", num, *v.Max)
+		if !v.MaxDisabled && num > v.Max {
+			return fmt.Errorf("value %d is more than the maximum %d", num, v.Max)
 		}
 		if v.Monotonic != "" && v.Monotonic != ValidationMonotonicIncreasing && v.Monotonic != ValidationMonotonicDecreasing {
 			return fmt.Errorf("number monotonicity can be either %q or %q", ValidationMonotonicIncreasing, ValidationMonotonicDecreasing)