Update required/ignore constraint behavior (#76)

Changes related to bufbuild/protovalidate#115

Makefile

@@ -15,7 +15,7 @@ ARGS ?= --strict --strict_message --strict_error
 # Set to use a different version of protovalidate-conformance.
 # Should be kept in sync with the version referenced in proto/buf.lock and
 # 'buf.build/gen/go/bufbuild/protovalidate/protocolbuffers/go' in go.mod.
-CONFORMANCE_VERSION ?= v0.5.1
+CONFORMANCE_VERSION ?= v0.5.3
 
 .PHONY: help
 help: ## Describe useful make targets

internal/evaluator/builder.go

@@ -203,9 +203,9 @@ func (bldr *Builder) buildField(
 	cache MessageCache,
 ) (field, error) {
 	fld := field{
-		Descriptor: fieldDescriptor,
-		Required:   fieldConstraints.GetRequired(),
-		Optional:   fieldDescriptor.HasPresence(),
+		Descriptor:  fieldDescriptor,
+		Required:    fieldConstraints.GetRequired(),
+		IgnoreEmpty: fieldDescriptor.HasPresence() || fieldConstraints.GetIgnoreEmpty(),
 	}
 	err := bldr.buildValue(fieldDescriptor, fieldConstraints, false, &fld.Value, cache)
 	return fld, err
@@ -218,15 +218,14 @@ func (bldr *Builder) buildValue(
 	valEval *value,
 	cache MessageCache,
 ) (err error) {
-	valEval.IgnoreEmpty = constraints.GetIgnoreEmpty()
 	steps := []func(
 		fdesc protoreflect.FieldDescriptor,
 		fieldConstraints *validate.FieldConstraints,
 		forItems bool,
 		valEval *value,
 		cache MessageCache,
 	) error{
-		bldr.processZeroValue,
+		bldr.processIgnoreEmpty,
 		bldr.processFieldExpressions,
 		bldr.processEmbeddedMessage,
 		bldr.processWrapperConstraints,
@@ -245,13 +244,20 @@ func (bldr *Builder) buildValue(
 	return nil
 }
 
-func (bldr *Builder) processZeroValue(
+func (bldr *Builder) processIgnoreEmpty(
 	fdesc protoreflect.FieldDescriptor,
-	_ *validate.FieldConstraints,
+	constraints *validate.FieldConstraints,
 	forItems bool,
 	val *value,
 	_ MessageCache,
 ) error {
+	// the only time we need to ignore empty on a value is if it's evaluating a
+	// field item (repeated element or map key/value).
+	val.IgnoreEmpty = forItems && constraints.GetIgnoreEmpty()
+	if !val.IgnoreEmpty {
+		// only need the zero value for checking ignore_empty constraint
+		return nil
+	}
 	val.Zero = fdesc.Default()
 	if forItems && fdesc.IsList() {
 		msg := dynamicpb.NewMessage(fdesc.ContainingMessage())

internal/evaluator/field.go

@@ -29,11 +29,10 @@ type field struct {
 	Descriptor protoreflect.FieldDescriptor
 	// Required indicates that the field must have a set value.
 	Required bool
-	// Optional indicates that the evaluators should not be applied to this field
-	// if the value is unset. Fields that contain messages, are prefixed with
-	// `optional`, or are part of a oneof are considered optional. evaluators
-	// will still be applied if the field is set as the zero value.
-	Optional bool
+	// IgnoreEmpty indicates if a field should skip validation on its zero value.
+	// This field is generally true for nullable fields or fields with the
+	// ignore_empty constraint explicitly set.
+	IgnoreEmpty bool
 }
 
 func (f field) Evaluate(val protoreflect.Value, failFast bool) error {
@@ -49,7 +48,7 @@ func (f field) EvaluateMessage(msg protoreflect.Message, failFast bool) (err err
 		}}}
 	}
 
-	if (f.Optional || f.Value.IgnoreEmpty) && !msg.Has(f.Descriptor) {
+	if f.IgnoreEmpty && !msg.Has(f.Descriptor) {
 		return nil
 	}
 

internal/evaluator/value.go

@@ -21,13 +21,14 @@ import (
 // value performs validation on any concrete value contained within a singular
 // field, repeated elements, or the keys/values of a map.
 type value struct {
-	// Zero is the default or zero-value for this value's type
-	Zero protoreflect.Value
 	// Constraints are the individual evaluators applied to a value
 	Constraints evaluators
 	// IgnoreEmpty indicates that the Constraints should not be applied if the
-	// field is unset or the default (typically zero) value.
+	// value is unset or the default (typically zero) value. This only applies to
+	// repeated elements or map keys/values with an ignore_empty rule.
 	IgnoreEmpty bool
+	// Zero is the default or zero-value for this value's type
+	Zero protoreflect.Value
 }
 
 func (v *value) Evaluate(val protoreflect.Value, failFast bool) error {