From e918bec740efeba88d96ae551dca3dbe45a19b21 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Fri, 28 Oct 2022 13:50:22 +1100
Subject: [PATCH] fixed leading content logic

---
 cmd/evaluate_all_command.go     | 2 +-
 cmd/evalute_sequence_command.go | 2 +-
 cmd/utils.go                    | 7 ++++---
 pkg/yqlib/decoder_yaml.go       | 9 +++++++--
 pkg/yqlib/yaml.go               | 2 ++
 5 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/cmd/evaluate_all_command.go b/cmd/evaluate_all_command.go
index fc761fdc..63b68871 100644
--- a/cmd/evaluate_all_command.go
+++ b/cmd/evaluate_all_command.go
@@ -75,7 +75,7 @@ func evaluateAll(cmd *cobra.Command, args []string) (cmdError error) {
 		return err
 	}
 
-	decoder, err := configureDecoder()
+	decoder, err := configureDecoder(true)
 	if err != nil {
 		return err
 	}
diff --git a/cmd/evalute_sequence_command.go b/cmd/evalute_sequence_command.go
index 3a352c18..53108165 100644
--- a/cmd/evalute_sequence_command.go
+++ b/cmd/evalute_sequence_command.go
@@ -97,7 +97,7 @@ func evaluateSequence(cmd *cobra.Command, args []string) (cmdError error) {
 
 	printer := yqlib.NewPrinter(encoder, printerWriter)
 
-	decoder, err := configureDecoder()
+	decoder, err := configureDecoder(false)
 	if err != nil {
 		return err
 	}
diff --git a/cmd/utils.go b/cmd/utils.go
index 0d303ff5..c6f5b2ab 100644
--- a/cmd/utils.go
+++ b/cmd/utils.go
@@ -56,7 +56,7 @@ func initCommand(cmd *cobra.Command, args []string) (string, []string, error) {
 	return expression, args, nil
 }
 
-func configureDecoder() (yqlib.Decoder, error) {
+func configureDecoder(evaluateTogether bool) (yqlib.Decoder, error) {
 	yqlibInputFormat, err := yqlib.InputFormatFromString(inputFormat)
 	if err != nil {
 		return nil, err
@@ -73,8 +73,9 @@ func configureDecoder() (yqlib.Decoder, error) {
 	case yqlib.TSVObjectInputFormat:
 		return yqlib.NewCSVObjectDecoder('\t'), nil
 	}
-
-	return yqlib.NewYamlDecoder(yqlib.ConfiguredYamlPreferences), nil
+	prefs := yqlib.ConfiguredYamlPreferences
+	prefs.EvaluateTogether = evaluateTogether
+	return yqlib.NewYamlDecoder(prefs), nil
 }
 
 func configurePrinterWriter(format yqlib.PrinterOutputFormat, out io.Writer) (yqlib.PrinterWriter, error) {
diff --git a/pkg/yqlib/decoder_yaml.go b/pkg/yqlib/decoder_yaml.go
index d5442d77..207ec01e 100644
--- a/pkg/yqlib/decoder_yaml.go
+++ b/pkg/yqlib/decoder_yaml.go
@@ -16,10 +16,11 @@ type yamlDecoder struct {
 	prefs          YamlPreferences
 	leadingContent string
 	readAnything   bool
+	firstFile      bool
 }
 
 func NewYamlDecoder(prefs YamlPreferences) Decoder {
-	return &yamlDecoder{prefs: prefs}
+	return &yamlDecoder{prefs: prefs, firstFile: true}
 }
 
 func (dec *yamlDecoder) processReadStream(reader *bufio.Reader) (io.Reader, string, error) {
@@ -58,7 +59,10 @@ func (dec *yamlDecoder) Init(reader io.Reader) error {
 	readerToUse := reader
 	leadingContent := ""
 	var err error
-	if dec.prefs.LeadingContentPreProcessing {
+	// if we 'evaluating together' - we only process the leading content
+	// of the first file - this ensures comments from subsequent files are
+	// merged together correctly.
+	if dec.prefs.LeadingContentPreProcessing && (!dec.prefs.EvaluateTogether || dec.firstFile) {
 		readerToUse, leadingContent, err = dec.processReadStream(bufio.NewReader(reader))
 		if err != nil {
 			return err
@@ -67,6 +71,7 @@ func (dec *yamlDecoder) Init(reader io.Reader) error {
 	dec.leadingContent = leadingContent
 	dec.readAnything = false
 	dec.decoder = *yaml.NewDecoder(readerToUse)
+	dec.firstFile = false
 	return nil
 }
 
diff --git a/pkg/yqlib/yaml.go b/pkg/yqlib/yaml.go
index 068e1ead..d7c8863a 100644
--- a/pkg/yqlib/yaml.go
+++ b/pkg/yqlib/yaml.go
@@ -4,6 +4,7 @@ type YamlPreferences struct {
 	LeadingContentPreProcessing bool
 	PrintDocSeparators          bool
 	UnwrapScalar                bool
+	EvaluateTogether            bool
 }
 
 func NewDefaultYamlPreferences() YamlPreferences {
@@ -11,6 +12,7 @@ func NewDefaultYamlPreferences() YamlPreferences {
 		LeadingContentPreProcessing: true,
 		PrintDocSeparators:          true,
 		UnwrapScalar:                true,
+		EvaluateTogether:            false,
 	}
 }