From 1537af979e2f9e2e11e6002211b8a684793ec34e Mon Sep 17 00:00:00 2001
From: Thomas Pelletier <thomas@pelletier.codes>
Date: Mon, 15 Aug 2022 11:25:32 -0400
Subject: [PATCH] Encode: don't inherit omitempty

Fixes #786.
---
 marshaler.go      | 10 +++++-----
 marshaler_test.go | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/marshaler.go b/marshaler.go
index 76896691..acb28831 100644
--- a/marshaler.go
+++ b/marshaler.go
@@ -346,8 +346,8 @@ func isNil(v reflect.Value) bool {
 	}
 }
 
-func shouldOmitEmpty(ctx encoderCtx, options valueOptions, v reflect.Value) bool {
-	return (ctx.options.omitempty || options.omitempty) && isEmptyValue(v)
+func shouldOmitEmpty(options valueOptions, v reflect.Value) bool {
+	return options.omitempty && isEmptyValue(v)
 }
 
 func (enc *Encoder) encodeKv(b []byte, ctx encoderCtx, options valueOptions, v reflect.Value) ([]byte, error) {
@@ -801,7 +801,7 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 
 	hasNonEmptyKV := false
 	for _, kv := range t.kvs {
-		if shouldOmitEmpty(ctx, kv.Options, kv.Value) {
+		if shouldOmitEmpty(kv.Options, kv.Value) {
 			continue
 		}
 		hasNonEmptyKV = true
@@ -818,7 +818,7 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 
 	first := true
 	for _, table := range t.tables {
-		if shouldOmitEmpty(ctx, table.Options, table.Value) {
+		if shouldOmitEmpty(table.Options, table.Value) {
 			continue
 		}
 		if first {
@@ -850,7 +850,7 @@ func (enc *Encoder) encodeTableInline(b []byte, ctx encoderCtx, t table) ([]byte
 
 	first := true
 	for _, kv := range t.kvs {
-		if shouldOmitEmpty(ctx, kv.Options, kv.Value) {
+		if shouldOmitEmpty(kv.Options, kv.Value) {
 			continue
 		}
 
diff --git a/marshaler_test.go b/marshaler_test.go
index ef444b7d..d7b4e520 100644
--- a/marshaler_test.go
+++ b/marshaler_test.go
@@ -1048,6 +1048,51 @@ func TestIssue786(t *testing.T) {
 	require.NoError(t, err)
 
 	require.Equal(t, "", string(b))
+
+	type General struct {
+		From      string `toml:"from,omitempty" json:"from,omitempty" comment:"from in graphite-web format, the local TZ is used"`
+		Randomize bool   `toml:"randomize" json:"randomize" comment:"randomize starting time with [0,step)"`
+	}
+
+	type Custom struct {
+		Name string `toml:"name" json:"name,omitempty" comment:"names for generator, braces are expanded like in shell"`
+		Type string `toml:"type,omitempty" json:"type,omitempty" comment:"type of generator"`
+		General
+	}
+	type Config struct {
+		General
+		Custom []Custom `toml:"custom,omitempty" json:"custom,omitempty" comment:"generators with custom parameters can be specified separately"`
+	}
+
+	buf := new(bytes.Buffer)
+	config := &Config{General: General{From: "-2d", Randomize: true}}
+	config.Custom = []Custom{{Name: "omit", General: General{Randomize: false}}}
+	config.Custom = append(config.Custom, Custom{Name: "present", General: General{From: "-2d", Randomize: true}})
+	encoder := toml.NewEncoder(buf)
+	encoder.Encode(config)
+
+	expected := `# from in graphite-web format, the local TZ is used
+from = '-2d'
+# randomize starting time with [0,step)
+randomize = true
+
+# generators with custom parameters can be specified separately
+[[custom]]
+# names for generator, braces are expanded like in shell
+name = 'omit'
+# randomize starting time with [0,step)
+randomize = false
+
+[[custom]]
+# names for generator, braces are expanded like in shell
+name = 'present'
+# from in graphite-web format, the local TZ is used
+from = '-2d'
+# randomize starting time with [0,step)
+randomize = true
+`
+
+	require.Equal(t, expected, buf.String())
 }
 
 func TestMarshalNestedAnonymousStructs(t *testing.T) {