Fix panic when gathering attribute (#3178)

We set the TF Dynamic type to nil so that we can handle it later:
https://github.com/pulumi/pulumi-terraform-bridge/blob/main/pkg/tfgen/generate.go#L547.

This means we have to ensure that we perform a nil check on the
attribute being processed; we did so in one location but missed this
one. This PR adds the missing check, plus a test to ensure the provider
will not panic.

Add missing nil check when gathering attributes
Add test for panic

Fixes pulumi/pulumi-terraform-provider#88.

Author: guineveresaenger

pkg/tfgen/generate_schema.go

@@ -107,6 +107,9 @@ func (nt *schemaNestedTypes) gatherFromMember(member moduleMember) {
 		nt.gatherFromProperties(p.Results(), member, member.name, member.rets, false)
 	case *variable:
 		contract.Assertf(member.config, `member.config`)
+		if member.typ == nil {
+			return
+		}
 		p := paths.NewProperyPath(paths.NewConfigPath(), member.propertyName)
 		nt.gatherFromPropertyType(p, member, member.name, "", member.typ, false)
 	}

pkg/tfgen/generate_schema_test.go

@@ -34,12 +34,14 @@ import (
 	pschema "github.com/pulumi/pulumi/pkg/v3/codegen/schema"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/diag"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/diag/colors"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/tokens"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	bridgetesting "github.com/pulumi/pulumi-terraform-bridge/v3/internal/testing"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfbridge"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfbridge/info"
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfgen/internal/paths"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfgen/internal/testprovider"
 	sdkv2 "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim/sdk-v2"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/x/muxer"
@@ -725,6 +727,54 @@ func TestRegress1626(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func Test_DynamicAttributeHandling(t *testing.T) {
+	t.Parallel()
+
+	t.Run("should not panic when processing variable with dynamic attribute", func(t *testing.T) {
+		dynamicVar := &variable{
+			name:         "dynamic_attr",
+			config:       true,
+			propertyName: paths.PropertyName{Key: "dynamic_attr", Name: tokens.Name("dynamicAttr")},
+			typ:          nil, // This represents a dynamic attribute
+		}
+
+		nt := &schemaNestedTypes{
+			nameToType: make(map[string]*schemaNestedType),
+		}
+		assert.NotPanics(t, func() { nt.gatherFromMember(dynamicVar) })
+		nt.gatherFromMember(dynamicVar)
+		assert.Empty(t, nt.nameToType, "Dynamic attributes should not generate nested types")
+	})
+
+	t.Run("should handle mixed variable types including dynamic", func(t *testing.T) {
+		strVar := &variable{
+			name:         "string_attr",
+			config:       true,
+			propertyName: paths.PropertyName{Key: "string_attr", Name: tokens.Name("stringAttr")},
+			typ: &propertyType{
+				kind: kindString,
+			},
+		}
+
+		dynamicVar := &variable{
+			name:         "dynamic_attr",
+			config:       true,
+			propertyName: paths.PropertyName{Key: "dynamic_attr", Name: tokens.Name("dynamicAttr")},
+			typ:          nil, // Dynamic attribute
+		}
+
+		// Create a module with both variables
+		mod := &module{
+			members: []moduleMember{strVar, dynamicVar},
+		}
+
+		assert.NotPanics(t, func() { gatherSchemaNestedTypesForModule(mod) })
+		result := gatherSchemaNestedTypesForModule(mod)
+		assert.NotNil(t, result, "Result should not be nil")
+		assert.Empty(t, result, "Dynamic attributes should not generate nested types")
+	})
+}
+
 func TestSinkHclDiagnostics(t *testing.T) {
 	t.Parallel()