panic invalid sdk diagnostics when building out proto diagnostics

Author: appilon

diag/diagnostic.go

@@ -1,6 +1,8 @@
 package diag
 
 import (
+	"fmt"
+
 	"github.com/zclconf/go-cty/cty"
 )
 
@@ -22,6 +24,23 @@ type Diagnostic struct {
 	AttributePath cty.Path
 }
 
+func (d Diagnostic) Validate() error {
+	var validSev bool
+	for _, sev := range severities {
+		if d.Severity == sev {
+			validSev = true
+			break
+		}
+	}
+	if !validSev {
+		return fmt.Errorf("invalid severity: %v", d.Severity)
+	}
+	if d.Summary == "" {
+		return fmt.Errorf("empty detail")
+	}
+	return nil
+}
+
 func FromErr(err error) Diagnostic {
 	return Diagnostic{
 		Severity: Error,
@@ -35,3 +54,5 @@ const (
 	Error Severity = iota
 	Warning
 )
+
+var severities = []Severity{Error, Warning}

internal/plugin/convert/diagnostics.go

@@ -1,6 +1,8 @@
 package convert
 
 import (
+	"fmt"
+
 	"github.com/hashicorp/go-cty/cty"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
@@ -65,6 +67,9 @@ func ProtoToDiags(ds []*proto.Diagnostic) diag.Diagnostics {
 func DiagsToProto(diags diag.Diagnostics) []*proto.Diagnostic {
 	var ds []*proto.Diagnostic
 	for _, d := range diags {
+		if err := d.Validate(); err != nil {
+			panic(fmt.Errorf("Invalid diagnostic: %s. This is always a bug in the provider implementation", err))
+		}
 		protoDiag := &proto.Diagnostic{
 			Summary:   d.Summary,
 			Detail:    d.Detail,