internal/encoding/yaml: canonicalize non-string map keys

We should probably not support non-string map keys at all.

But until that time, at the very least canonicalize non-string
map keys.

Signed-off-by: Marcel van Lohuizen <mpvl@golang.org>

Change-Id: Idf6efb83df61c1d5920c6e1515ed27956723924a
Signed-off-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/527817
Unity-Result: CUEcueckoo <cueckoo@cuelang.org>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Paul Jolly <paul@myitcv.io>

Author: mpvl

internal/third_party/yaml/decode.go

@@ -539,13 +539,35 @@ func (d *decoder) scalar(n *node) ast.Expr {
 }
 
 func (d *decoder) label(n *node) ast.Label {
-	if ast.IsValidIdent(n.value) && !internal.IsDefOrHidden(n.value) {
-		return d.ident(n, n.value)
+	pos := d.pos(n.startPos)
+
+	switch x := d.scalar(n).(type) {
+	case *ast.BasicLit:
+		if x.Kind == token.STRING {
+			if ast.IsValidIdent(n.value) && !internal.IsDefOrHidden(n.value) {
+				return &ast.Ident{
+					NamePos: pos,
+					Name:    n.value,
+				}
+			}
+			ast.SetPos(x, pos)
+			return x
+		}
+
+		return &ast.BasicLit{
+			ValuePos: pos,
+			Kind:     token.STRING,
+			Value:    literal.Label.Quote(x.Value),
+		}
+
+	default:
+		d.p.failf(n.startPos.line, "invalid label: %q", n.value)
 	}
+
 	return &ast.BasicLit{
-		ValuePos: d.start(n),
+		ValuePos: pos,
 		Kind:     token.STRING,
-		Value:    literal.Label.Quote(n.value),
+		Value:    "<invalid>",
 	}
 }
 

internal/third_party/yaml/decode_test.go

@@ -165,7 +165,7 @@ var unmarshalTests = []struct {
 		`"_#foo": 1`,
 	}, {
 		"~: null key",
-		`"~": "null key"`,
+		`"null": "null key"`,
 	}, {
 		`empty:
 apple: "newline"`,
@@ -260,6 +260,15 @@ apple: "newline"`,
 	}, {
 		"{ a: 1, b: {c: 1} }",
 		`a: 1, b: {c: 1}`,
+	}, {
+		`
+True: 1
+Null: 1
+.Inf: 2
+`,
+		`"true": 1
+"null": 1
+"+Inf": 2`,
 	},
 
 	// Some cross type conversions
@@ -736,6 +745,22 @@ func TestUnmarshal(t *testing.T) {
 	}
 }
 
+// For debug purposes: do not delete.
+func TestX(t *testing.T) {
+	y := `
+`
+	y = strings.TrimSpace(y)
+	if len(y) == 0 {
+		t.Skip()
+	}
+
+	expr, err := callUnmarshal(t, y)
+	if _, ok := err.(*yaml.TypeError); !ok && err != nil {
+		t.Fatal(err)
+	}
+	t.Error(cueStr(expr))
+}
+
 // // TODO(v3): This test should also work when unmarshaling onto an interface{}.
 // func (s *S) TestUnmarshalFullTimestamp(c *C) {
 // 	// Full timestamp in same format as encoded. This is confirmed to be