From 9b759f39fcf9fad941c390700358a06ecf96bd72 Mon Sep 17 00:00:00 2001
From: korvahkh <92224397+korvahkh@users.noreply.github.com>
Date: Sat, 11 May 2024 14:36:56 -0500
Subject: [PATCH] encoding/json: Properly marshal `#no_nil` unions

Previously the first variant of a `#no_nil` would always be output as
`null`, and following variants would be treated as the wrong type.
---
 core/encoding/json/marshal.odin | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/core/encoding/json/marshal.odin b/core/encoding/json/marshal.odin
index f45cdb1f1..83c0f8f79 100644
--- a/core/encoding/json/marshal.odin
+++ b/core/encoding/json/marshal.odin
@@ -469,12 +469,15 @@ marshal_to_writer :: proc(w: io.Writer, v: any, opt: ^Marshal_Options) -> (err:
 		case: panic("Invalid union tag type")
 		}
 
-		if v.data == nil || tag == 0 {
-			io.write_string(w, "null") or_return
-		} else {
-			id := info.variants[tag-1].id
-			return marshal_to_writer(w, any{v.data, id}, opt)
+		if !info.no_nil {
+			if tag == 0 {
+				io.write_string(w, "null") or_return
+				return nil
+			}
+			tag -= 1
 		}
+		id := info.variants[tag].id
+		return marshal_to_writer(w, any{v.data, id}, opt)
 
 	case runtime.Type_Info_Enum:
 		if !opt.use_enum_names || len(info.names) == 0 {