From fd1175a70ca1989a6dc15722467e69e7127cca8d Mon Sep 17 00:00:00 2001
From: vulragrag-star <vulragrag@gmail.com>
Date: Mon, 28 Sep 2026 08:54:04 +0800
Subject: [PATCH] jsonio: encode nested none as null

Top-level Write already skips none, and record fields omit none, but
array/map/error paths called writePrimitive on TypeNone and panicked
(unsupported id=30). Emit JSON null for nested none, matching arrowio.

Fixes #7314
---
 sio/jsonio/none_nested_test.go | 63 ++++++++++++++++++++++++++++++++++
 sio/jsonio/writer.go           |  5 +++
 sio/jsonio/ztests/none.yaml    |  6 ++++
 3 files changed, 74 insertions(+)
 create mode 100644 sio/jsonio/none_nested_test.go

diff --git a/sio/jsonio/none_nested_test.go b/sio/jsonio/none_nested_test.go
new file mode 100644
index 000000000..d39e704d4
--- /dev/null
+++ b/sio/jsonio/none_nested_test.go
@@ -0,0 +1,63 @@
+package jsonio
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/brimdata/super"
+	"github.com/brimdata/super/sio"
+	"github.com/brimdata/super/sup"
+)
+
+func TestNestedNoneJSON(t *testing.T) {
+	cases := []struct {
+		in   string
+		want string
+	}{
+		{"none", ""},
+		{"[none]", "[null]\n"},
+		{"{a:[none]}", `{"a":[null]}` + "\n"},
+		{"error(none)", `{"error":null}` + "\n"},
+		{"{a:1,b?:none::int64}", `{"a":1}` + "\n"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.in, func(t *testing.T) {
+			val, err := sup.ParseValue(super.NewContext(), tc.in)
+			if err != nil {
+				t.Fatalf("parse: %v", err)
+			}
+			var buf bytes.Buffer
+			w := NewWriter(sio.NopCloser(&buf), WriterOpts{})
+			if err := w.Write(val); err != nil {
+				t.Fatalf("write: %v", err)
+			}
+			if err := w.Close(); err != nil {
+				t.Fatalf("close: %v", err)
+			}
+			got := buf.String()
+			if got != tc.want {
+				t.Fatalf("got %q want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestNestedNoneNoPanic(t *testing.T) {
+	for _, in := range []string{"[none]", "{a:[none]}", "error(none)", "values none | values len(this)"} {
+		// last case is spq; skip — covered by CLI. Keep value-level only.
+		if strings.Contains(in, "|") {
+			continue
+		}
+		val, err := sup.ParseValue(super.NewContext(), in)
+		if err != nil {
+			t.Fatalf("parse %s: %v", in, err)
+		}
+		var buf bytes.Buffer
+		w := NewWriter(sio.NopCloser(&buf), WriterOpts{})
+		if err := w.Write(val); err != nil {
+			t.Fatalf("write %s: %v", in, err)
+		}
+		_ = w.Close()
+	}
+}
diff --git a/sio/jsonio/writer.go b/sio/jsonio/writer.go
index 701024b06..5720f2bc7 100644
--- a/sio/jsonio/writer.go
+++ b/sio/jsonio/writer.go
@@ -70,6 +70,11 @@ func (w *Writer) Write(val super.Value) error {
 }
 
 func (w *Writer) writeAny(tab int, val super.Value) {
+	// Nested none: emit null (arrowio does the same). Top-level Write still skips none.
+	if val.IsNone() {
+		w.writeColor([]byte("null"), nullColor)
+		return
+	}
 	val = val.Under()
 	if val.IsNull() {
 		w.writeColor([]byte("null"), nullColor)
diff --git a/sio/jsonio/ztests/none.yaml b/sio/jsonio/ztests/none.yaml
index 1f306e665..c4c4c5202 100644
--- a/sio/jsonio/ztests/none.yaml
+++ b/sio/jsonio/ztests/none.yaml
@@ -7,7 +7,13 @@ input: |
   {a:3,b?:none::int64}
   none
   none::int64
+  [none]
+  {a:[none]}
+  error(none)
 
 output: |
   {"a":1,"b":2}
   {"a":3}
+  [null]
+  {"a":[null]}
+  {"error":null}