disable seq indent option

emitterc.go

@@ -226,7 +226,7 @@ func yaml_emitter_append_tag_directive(emitter *yaml_emitter_t, value *yaml_tag_
 }
 
 // Increase the indentation level.
-func yaml_emitter_increase_indent(emitter *yaml_emitter_t, flow, indentless bool) bool {
+func yaml_emitter_increase_indent(emitter *yaml_emitter_t, flow, indentless bool, seq bool) bool {
 	emitter.indents = append(emitter.indents, emitter.indent)
 	if emitter.indent < 0 {
 		if flow {
@@ -243,6 +243,9 @@ func yaml_emitter_increase_indent(emitter *yaml_emitter_t, flow, indentless bool
 			// Everything else aligns to the chosen indentation.
 			emitter.indent = emitter.best_indent*((emitter.indent+emitter.best_indent)/emitter.best_indent)
 		}
+		if seq {
+			emitter.indent = emitter.indent - 2
+		}
 	}
 	return true
 }
@@ -534,7 +537,7 @@ func yaml_emitter_emit_flow_sequence_item(emitter *yaml_emitter_t, event *yaml_e
 		if !yaml_emitter_write_indicator(emitter, []byte{'['}, true, true, false) {
 			return false
 		}
-		if !yaml_emitter_increase_indent(emitter, true, false) {
+		if !yaml_emitter_increase_indent(emitter, true, false, false) {
 			return false
 		}
 		emitter.flow_level++
@@ -617,7 +620,7 @@ func yaml_emitter_emit_flow_mapping_key(emitter *yaml_emitter_t, event *yaml_eve
 		if !yaml_emitter_write_indicator(emitter, []byte{'{'}, true, true, false) {
 			return false
 		}
-		if !yaml_emitter_increase_indent(emitter, true, false) {
+		if !yaml_emitter_increase_indent(emitter, true, false, false) {
 			return false
 		}
 		emitter.flow_level++
@@ -728,7 +731,9 @@ func yaml_emitter_emit_flow_mapping_value(emitter *yaml_emitter_t, event *yaml_e
 // Expect a block item node.
 func yaml_emitter_emit_block_sequence_item(emitter *yaml_emitter_t, event *yaml_event_t, first bool) bool {
 	if first {
-		if !yaml_emitter_increase_indent(emitter, false, false) {
+		seq := emitter.mapping_context && (emitter.column == 0 || !emitter.indention) &&
+			emitter.disable_sequence_indent
+		if !yaml_emitter_increase_indent(emitter, false, false, seq){
 			return false
 		}
 	}
@@ -764,7 +769,7 @@ func yaml_emitter_emit_block_sequence_item(emitter *yaml_emitter_t, event *yaml_
 // Expect a block key node.
 func yaml_emitter_emit_block_mapping_key(emitter *yaml_emitter_t, event *yaml_event_t, first bool) bool {
 	if first {
-		if !yaml_emitter_increase_indent(emitter, false, false) {
+		if !yaml_emitter_increase_indent(emitter, false, false, false) {
 			return false
 		}
 	}
@@ -896,7 +901,7 @@ func yaml_emitter_emit_scalar(emitter *yaml_emitter_t, event *yaml_event_t) bool
 	if !yaml_emitter_process_tag(emitter) {
 		return false
 	}
-	if !yaml_emitter_increase_indent(emitter, true, false) {
+	if !yaml_emitter_increase_indent(emitter, true, false, false) {
 		return false
 	}
 	if !yaml_emitter_process_scalar(emitter) {

encode_test.go

@@ -656,6 +656,37 @@ func (s *S) TestSetIndent(c *C) {
 	c.Assert(buf.String(), Equals, "a:\n        b:\n                c: d\n")
 }
 
+func (s *S) TestDisableSeqIndentDefault(c *C) {
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
+	enc.DisableSeqIndent()
+	err := enc.Encode(map[string]interface{}{"a": []string{"b", "c"}})
+	c.Assert(err, Equals, nil)
+	err = enc.Close()
+	c.Assert(err, Equals, nil)
+	// The default indent is 4, so these sequence elements get 2 indents as before
+	c.Assert(buf.String(), Equals, `a:
+  - b
+  - c
+`)
+}
+
+func (s *S) TestDisableSequenceWithSetIndent(c *C) {
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
+	enc.DisableSeqIndent()
+	enc.SetIndent(2)
+	err := enc.Encode(map[string]interface{}{"a": []string{"b", "c"}})
+	c.Assert(err, Equals, nil)
+	err = enc.Close()
+	c.Assert(err, Equals, nil)
+	// The sequence indent is 2, so these sequence elements don't get indented at all
+	c.Assert(buf.String(), Equals, `a:
+- b
+- c
+`)
+}
+
 func (s *S) TestSortedOutput(c *C) {
 	order := []interface{}{
 		false,

go.mod

@@ -2,4 +2,4 @@ module "gopkg.in/yaml.v3"
 
 require (
 	"gopkg.in/check.v1" v0.0.0-20161208181325-20d25e280405
-)
+)

go.sum

@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

yaml.go

@@ -278,6 +278,11 @@ func (e *Encoder) SetIndent(spaces int) {
 	e.encoder.indent = spaces
 }
 
+// DisableSeqIndent disables the indentation for sequence items.
+func (e *Encoder) DisableSeqIndent() {
+	e.encoder.emitter.disable_sequence_indent = true
+}
+
 // Close closes the encoder by writing any remaining data.
 // It does not write a stream terminating string "...".
 func (e *Encoder) Close() (err error) {

yamlh.go

@@ -742,6 +742,8 @@ type yaml_emitter_t struct {
 
 	indent int // The current indentation level.
 
+	disable_sequence_indent bool // Disable the indentation for sequence items
+
 	flow_level int // The current flow level.
 
 	root_context       bool // Is it the document root context?