From 4d4d76d65bc45d49117cf85fd086ad5401a69fda Mon Sep 17 00:00:00 2001
From: Hitalo Souza <63821277+enghitalo@users.noreply.github.com>
Date: Mon, 10 Apr 2023 12:57:02 -0300
Subject: [PATCH] json2: fix encoding of nested maps like
 map[string]map[string]int (#17924)

---
 vlib/x/json2/encode_struct_test.v | 14 +++++------
 vlib/x/json2/encoder.v            | 40 +++++++++++++++++--------------
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/vlib/x/json2/encode_struct_test.v b/vlib/x/json2/encode_struct_test.v
index bcc942a6f9..a1274285bd 100644
--- a/vlib/x/json2/encode_struct_test.v
+++ b/vlib/x/json2/encode_struct_test.v
@@ -265,11 +265,11 @@ fn test_maps() {
 			'1': 1
 		}
 	}) == '{"val":{"1":1}}'
-	// assert json.encode(StructType[map[string]map[string]int]{
-	// 	val: {
-	// 		'a': {
-	// 			'1': 1
-	// 		}
-	// 	}
-	// }) == '{"val":{"a":{"1":1}}}'
+	assert json.encode(StructType[map[string]map[string]int]{
+		val: {
+			'a': {
+				'1': 1
+			}
+		}
+	}) == '{"val":{"a":{"1":1}}}'
 }
diff --git a/vlib/x/json2/encoder.v b/vlib/x/json2/encoder.v
index 2b200e172e..4014c181a9 100644
--- a/vlib/x/json2/encoder.v
+++ b/vlib/x/json2/encoder.v
@@ -124,6 +124,26 @@ fn (e &Encoder) encode_any(val Any, level int, mut wr io.Writer) ! {
 	}
 }
 
+fn (e &Encoder) encode_map[T](value T, level int, mut wr io.Writer) ! {
+	wr.write(json2.curly_open)!
+	mut idx := 0
+	for k, v in value {
+		e.encode_newline(level, mut wr)!
+		e.encode_string(k.str(), mut wr)!
+		wr.write(json2.colon_bytes)!
+		if e.newline != 0 {
+			wr.write(json2.space_bytes)!
+		}
+		e.encode_value_with_level(v, level + 1, mut wr)!
+		if idx < value.len - 1 {
+			wr.write(json2.comma_bytes)!
+		}
+		idx++
+	}
+	e.encode_newline(level, mut wr)!
+	wr.write(json2.curly_close)!
+}
+
 fn (e &Encoder) encode_value_with_level[T](val T, level int, mut wr io.Writer) ! {
 	$if T is string {
 		e.encode_string(val, mut wr)!
@@ -133,7 +153,7 @@ fn (e &Encoder) encode_value_with_level[T](val T, level int, mut wr io.Writer) !
 		// weird quirk but val is destructured immediately to Any
 		e.encode_any(val, level, mut wr)!
 	} $else $if T is $map {
-		// FIXME - `e.encode_struct` can not encode `map[string]map[string]int` type
+		e.encode_map(val, level, mut wr)!
 	} $else $if T is []Any {
 		e.encode_any(val, level, mut wr)!
 	} $else $if T is Encodable {
@@ -261,23 +281,7 @@ fn (e &Encoder) encode_struct[U](val U, level int, mut wr io.Writer) ! {
 			} $else $if field.typ is $struct {
 				e.encode_struct(value, level + 1, mut wr)!
 			} $else $if field.is_map {
-				wr.write(json2.curly_open)!
-				mut idx := 0
-				for k, v in value {
-					e.encode_newline(level, mut wr)!
-					e.encode_string(k.str(), mut wr)!
-					wr.write(json2.colon_bytes)!
-					if e.newline != 0 {
-						wr.write(json2.space_bytes)!
-					}
-					e.encode_value_with_level(v, level + 1, mut wr)!
-					if idx < value.len - 1 {
-						wr.write(json2.comma_bytes)!
-					}
-					idx++
-				}
-				e.encode_newline(level, mut wr)!
-				wr.write(json2.curly_close)!
+				e.encode_map(value, level + 1, mut wr)!
 			} $else $if field.is_enum {
 				// TODO - replace for `field.typ is $enum`
 				wr.write(int(val.$(field.name)).str().bytes())!