Change v8n context.Type and Parent on typedefs

I did an audit of how we are handling pointerness and aliases in
validators.  In a word - inconsistent.

I went through each validator and added test cases where they were
missing (previous commits). This commit changes how Context.Type is
defined for typedefs. Previously Context.Type was the potentially
aliased and potentially pointerful type for struct fields, but the
"real" concrete type for typedefs.  Now it is consistent, and validators
need to unalias and unpointer types (which they had to do anyway because
it was inconsistent.

Author: thockin

staging/src/k8s.io/code-generator/cmd/validation-gen/validation.go

@@ -461,13 +461,10 @@ func (td *typeDiscoverer) discover(t *types.Type, fldPath *field.Path) (*typeNod
 	// This should only ever hit Struct and Alias types, since that is the only
 	// opportunity to have type-attached comments to process.
 	context := validators.Context{
-		Scope: validators.ScopeType,
-		Type:  t,
-		Path:  fldPath,
-	}
-	if t.Kind == types.Alias {
-		context.Parent = t
-		context.Type = t.Underlying
+		Scope:  validators.ScopeType,
+		Type:   t,
+		Parent: nil,
+		Path:   fldPath,
 	}
 	if validations, err := td.validator.ExtractValidations(context, t.CommentLines); err != nil {
 		return nil, fmt.Errorf("%v: %w", fldPath, err)

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/each.go

@@ -76,10 +76,9 @@ func (listTypeTagValidator) ValidScopes() sets.Set[Scope] {
 }
 
 func (lttv listTypeTagValidator) GetValidations(context Context, _ []string, payload string) (Validations, error) {
-	t := context.Type
-	if t.Kind == types.Alias {
-		t = t.Underlying
-	}
+	// We don't support pointers to lists, but other validators use realType()
+	// for this sort of check, so let's be consistent.
+	t := realType(context.Type)
 	if t.Kind != types.Slice && t.Kind != types.Array {
 		return Validations{}, fmt.Errorf("can only be used on list types")
 	}
@@ -88,6 +87,7 @@ func (lttv listTypeTagValidator) GetValidations(context Context, _ []string, pay
 	case "atomic", "set":
 		// Allowed but no special handling.
 	case "map":
+		// NOTE: maps of pointers are not supported, and that is enforced way before this point.
 		if realType(t.Elem).Kind != types.Struct {
 			return Validations{}, fmt.Errorf("only lists of structs can be list-maps")
 		}
@@ -135,10 +135,9 @@ func (listMapKeyTagValidator) ValidScopes() sets.Set[Scope] {
 }
 
 func (lmktv listMapKeyTagValidator) GetValidations(context Context, _ []string, payload string) (Validations, error) {
-	t := context.Type
-	if t.Kind == types.Alias {
-		t = t.Underlying
-	}
+	// We don't support pointers to lists, but other validators use realType()
+	// for this sort of check, so let's be consistent.
+	t := realType(context.Type)
 	if t.Kind != types.Slice && t.Kind != types.Array {
 		return Validations{}, fmt.Errorf("can only be used on list types")
 	}
@@ -218,10 +217,9 @@ var (
 )
 
 func (evtv eachValTagValidator) GetValidations(context Context, _ []string, payload string) (Validations, error) {
-	t := context.Type
-	if t.Kind == types.Alias {
-		t = t.Underlying
-	}
+	// We don't support pointers to lists, but other validators use realType()
+	// for this sort of check, so let's be consistent.
+	t := realType(context.Type)
 	switch t.Kind {
 	case types.Slice, types.Array, types.Map:
 	default:
@@ -353,10 +351,9 @@ var (
 )
 
 func (ektv eachKeyTagValidator) GetValidations(context Context, _ []string, payload string) (Validations, error) {
-	t := context.Type
-	if t.Kind == types.Alias {
-		t = t.Underlying
-	}
+	// We don't support pointers to lists, but other validators use realType()
+	// for this sort of check, so let's be consistent.
+	t := realType(context.Type)
 	if t.Kind != types.Map {
 		return Validations{}, fmt.Errorf("can only be used on map types")
 	}

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/limits.go

@@ -55,6 +55,8 @@ var (
 func (minimumTagValidator) GetValidations(context Context, _ []string, payload string) (Validations, error) {
 	var result Validations
 
+	// This tag can apply to value and pointer fields, as well as typedefs
+	// (which should never be pointers). We need to check the concrete type.
 	if t := realType(context.Type); !types.IsInteger(t) {
 		return result, fmt.Errorf("can only be used on integer types (%s)", rootTypeString(context.Type, t))
 	}

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/subfield.go

@@ -54,6 +54,8 @@ var (
 )
 
 func (stv subfieldTagValidator) GetValidations(context Context, args []string, payload string) (Validations, error) {
+	// This tag can apply to value and pointer fields, as well as typedefs
+	// (which should never be pointers). We need to check the concrete type.
 	t := realType(context.Type)
 	if t.Kind != types.Struct {
 		return Validations{}, fmt.Errorf("can only be used on struct types")

staging/src/k8s.io/code-generator/cmd/validation-gen/validators/validators.go

@@ -133,25 +133,21 @@ type Context struct {
 	Scope Scope
 
 	// Type provides details about the type being validated.  When Scope is
-	// ScopeType, this is the underlying type.  When Scope is ScopeField, this
-	// is the field's type (including any pointerness).  When Scope indicates a
-	// list-value, map-key, or map-value, this is the type of that key or
-	// value.
+	// ScopeType, this is the newly defined type.  When Scope is ScopeField,
+	// this is the field's type (which may be a pointer, an alias, or both).
+	// When Scope indicates a list-value, map-key, or map-value, this is the
+	// type of that key or value (which, again, may be a pointer, and alias, or
+	// both).
 	Type *types.Type
 
-	// Parent provides details about the logical parent type of the type being
-	// validated, when applicable.  When Scope is ScopeType, this is the
-	// newly-defined type (when it exists - gengo handles struct-type
-	// definitions differently that other "alias" type definitions).  When
-	// Scope is ScopeField, this is the field's parent struct's type.  When
-	// Scope indicates a list-value, map-key, or map-value, this is the type of
-	// the whole list or map.
-	//
-	// Because of how gengo handles struct-type definitions, this field may be
-	// nil in those cases.
+	// Parent provides details about the logical parent type of the object
+	// being validated, when applicable.  When Scope is ScopeField, this is the
+	// containing struct's type.  When Scope indicates a list-value, map-key,
+	// or map-value, this is the type of the whole list or map. When Scope is
+	// ScopeType, this is nil.
 	Parent *types.Type
 
-	// Member provides details about a field within a struct, when Scope is
+	// Member provides details about a field within a struct when Scope is
 	// ScopeField.  For all other values of Scope, this will be nil.
 	Member *types.Member