Evaluate $output: false after $merge/$replace

output.go

@@ -5,12 +5,12 @@ import (
 )
 
 func findOutputs(obj any) (any, []any, error) {
-	switch objType := obj.(type) {
+	switch obj2 := obj.(type) {
 	case map[string]any:
-		return findOutputsMap(objType)
+		return findOutputsMap(obj2)
 
 	case []any:
-		return findOutputsList(objType)
+		return findOutputsList(obj2)
 
 	default:
 		return obj, []any{}, nil
@@ -69,3 +69,60 @@ func findOutputsList(obj []any) (any, []any, error) {
 
 	return ret, outs, nil
 }
+
+func filterOutput(obj any) (any, error) {
+	switch obj2 := obj.(type) {
+	case map[string]any:
+		return filterOutputMap(obj2)
+
+	case []any:
+		return filterOutputList(obj2)
+
+	default:
+		return obj, nil
+	}
+}
+
+func filterOutputMap(obj map[string]any) (any, error) {
+	output, obj := popMapBoolValue(obj, "$output", false)
+	if output {
+		return nil, nil
+	}
+
+	return filterMap(obj, func(k string, v any) (map[string]any, error) {
+		v2, err := filterOutput(v)
+		if err != nil {
+			return nil, err
+		}
+
+		if v2 == nil {
+			return nil, nil
+		}
+
+		return map[string]any{k: v2}, nil
+	})
+}
+
+func filterOutputList(obj []any) (any, error) {
+	output, obj, err := popListMapBoolValue(obj, "$output", false)
+	if err != nil {
+		return nil, err
+	}
+
+	if output {
+		return nil, nil
+	}
+
+	return filterList(obj, func(v any) ([]any, error) {
+		v2, err := filterOutput(v)
+		if err != nil {
+			return nil, err
+		}
+
+		if v2 == nil {
+			return nil, nil
+		}
+
+		return []any{v2}, nil
+	})
+}

parser.go

@@ -39,12 +39,12 @@ import (
 //
 // Output phase 1 (process)
 //   - $merge
+//   - $replace: map
 //   - $replace: string
-//   - $output: false
 //   - $encode
 //
 // Output phase 2 (output)
-//   - $output: true
+//   - $output
 type Parser struct {
 	docs  []any
 	debug bool
@@ -240,7 +240,24 @@ func (p *Parser) OutputDocumentsIndex(index int) ([]any, error) {
 		outs = append(outs, obj)
 	}
 
-	err = validate(obj)
+	outs, err = filterList(outs, func(v any) ([]any, error) {
+		v2, err := filterOutput(v)
+		if err != nil {
+			return nil, err
+		}
+
+		if v2 == nil {
+			return nil, nil
+		}
+
+		err = validate(v2)
+		if err != nil {
+			return nil, err
+		}
+
+		return []any{v2}, nil
+	})
+
 	if err != nil {
 		return nil, err
 	}

process.go

@@ -44,11 +44,6 @@ func processMap(obj map[string]any, mergeFrom any, mergeFromDocs []any, depth in
 		return processMapReplace(mergeFrom, mergeFromDocs, m, depth)
 	}
 
-	output, found := getMapBoolValue(obj, "$output")
-	if found && !output {
-		return nil, nil
-	}
-
 	encode := getMapStringValue(obj, "$encode")
 	if encode != "" {
 		delete(obj, "$encode")
@@ -138,10 +133,6 @@ func processList(obj []any, mergeFrom any, mergeFromDocs []any, depth int) (any,
 		return processListReplace(mergeFrom, mergeFromDocs, m, depth)
 	}
 
-	if hasListMapBoolValue(obj, "$output", false) {
-		return nil, nil
-	}
-
 	encode, obj, err := popListMapStringValue(obj, "$encode")
 	if err != nil {
 		return nil, err

tests/process-replace-before-output/a.yaml

@@ -0,0 +1,5 @@
+a:
+  b: 2
+  $output: false
+c:
+  $replace: a.b

tests/process-replace-before-output/cmd

@@ -0,0 +1 @@
+bkl a.yaml

tests/process-replace-before-output/expected

@@ -0,0 +1 @@
+c: 2

util.go

@@ -233,7 +233,12 @@ func popListMapStringValue(l []any, k string) (string, []any, error) {
 func filterMap(m map[string]any, filter func(string, any) (map[string]any, error)) (map[string]any, error) {
 	ret := map[string]any{}
 
-	for k, v := range m {
+	ks := polyfill.MapsKeys(m)
+	polyfill.SlicesSort(ks)
+
+	for _, k := range ks {
+		v := m[k]
+
 		m2, err := filter(k, v)
 		if err != nil {
 			return nil, err