From 291e2f6df08a8fb35ed1bb1d0a6864822fce1f72 Mon Sep 17 00:00:00 2001
From: Matthew Nibecker <hello@mattnibecker.com>
Date: Fri, 11 Sep 2026 12:58:37 -0700
Subject: [PATCH] sfmt: Support optional fields in record expressions

---
 compiler/sfmt/ast.go                     |  3 +++
 compiler/sfmt/dag.go                     |  3 +++
 compiler/sfmt/ztests/optional-field.yaml | 13 +++++++++++++
 3 files changed, 19 insertions(+)
 create mode 100644 compiler/sfmt/ztests/optional-field.yaml

diff --git a/compiler/sfmt/ast.go b/compiler/sfmt/ast.go
index 81e927ce5..28c70bc97 100644
--- a/compiler/sfmt/ast.go
+++ b/compiler/sfmt/ast.go
@@ -185,6 +185,9 @@ func (c *canon) expr(e ast.Expr, parent string) {
 			switch e := elem.(type) {
 			case *ast.FieldElem:
 				c.write(sup.QuotedName(e.Name.Text))
+				if e.Opt {
+					c.write("?")
+				}
 				c.write(":")
 				c.expr(e.Value, "")
 			case *ast.ExprElem:
diff --git a/compiler/sfmt/dag.go b/compiler/sfmt/dag.go
index 5af4bd7a5..f5db9b0af 100644
--- a/compiler/sfmt/dag.go
+++ b/compiler/sfmt/dag.go
@@ -220,6 +220,9 @@ func (c *canonDAG) recordElems(elems []dag.RecordElem) {
 		switch e := elem.(type) {
 		case *dag.Field:
 			c.write(sup.QuotedName(e.Name))
+			if e.Opt {
+				c.write("?")
+			}
 			c.write(":")
 			c.expr(e.Value, "")
 		case *dag.Spread:
diff --git a/compiler/sfmt/ztests/optional-field.yaml b/compiler/sfmt/ztests/optional-field.yaml
new file mode 100644
index 000000000..fb28e96ce
--- /dev/null
+++ b/compiler/sfmt/ztests/optional-field.yaml
@@ -0,0 +1,13 @@
+script: |
+  super compile -C 'values {x?:1}'
+  echo ===
+  super compile -dag -C 'values {x?:1}'
+
+outputs:
+  - name: stdout
+    data: |
+      values {x?:1}
+      ===
+      null
+      | values {x?:1}
+      | output main