internal/core/convert: fix conversion from float

Conversion from Go types big.Float, float32 and
float64 always added an error to the OpContext even
when no error had occured.

Fixes #749

Closes #761
cuelang/cue#761

GitOrigin-RevId: 3476e9fc96bde56801c1cadda0004c529e70af39
Change-Id: I253846087ddaf5dbfd9bd2ade4cf917101e482e5
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8721
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cmd/cue/cmd/testdata/script/issue749.txt

@@ -0,0 +1,13 @@
+cue eval ./float.cue
+cmp stderr expect-stderr
+cmp stdout expect-stdout
+-- float.cue --
+import "strconv"
+
+x : strconv.ParseFloat("3.14", 32)
+y : strconv.ParseFloat("3.14", 64)
+
+-- expect-stderr --
+-- expect-stdout --
+x: 3.140000104904175
+y: 3.14

cue/types_test.go

@@ -978,6 +978,38 @@ func TestFill2(t *testing.T) {
 	}
 }
 
+func TestFillFloat(t *testing.T) {
+	// This tests panics for issue #749
+
+	want := `{
+	x: 3.14
+}`
+
+	filltest := func(x interface{}) {
+		r := &Runtime{}
+		i, err := r.Compile("test", `
+	x: number
+	`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		i, err = i.Fill(x, "x")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		got := fmt.Sprint(i.Value())
+		if got != want {
+			t.Errorf("got:  %s\nwant: %s", got, want)
+		}
+	}
+
+	filltest(float32(3.14))
+	filltest(float64(3.14))
+	filltest(big.NewFloat(3.14))
+}
+
 func TestValue_LookupDef(t *testing.T) {
 	r := &Runtime{}
 

internal/core/convert/go.go

@@ -274,7 +274,9 @@ func convertRec(ctx *adt.OpContext, nilIsTop bool, x interface{}) adt.Value {
 	case *big.Float:
 		n := &adt.Num{Src: src, K: adt.FloatKind}
 		_, _, err := n.X.SetString(v.String())
-		ctx.AddErr(errors.Promote(err, "invalid float"))
+		if err != nil {
+			return ctx.AddErr(errors.Promote(err, "invalid float"))
+		}
 		return n
 
 	case *apd.Decimal:
@@ -355,13 +357,17 @@ func convertRec(ctx *adt.OpContext, nilIsTop bool, x interface{}) adt.Value {
 		return toUint(ctx, uint64(v))
 	case float64:
 		n := &adt.Num{Src: src, K: adt.FloatKind}
-		_, _, err := n.X.SetString(fmt.Sprintf("%g", v))
-		ctx.AddErr(errors.Promote(err, "invalid float"))
+		_, _, err := n.X.SetString(fmt.Sprint(v))
+		if err != nil {
+			return ctx.AddErr(errors.Promote(err, "invalid float"))
+		}
 		return n
 	case float32:
 		n := &adt.Num{Src: src, K: adt.FloatKind}
-		_, _, err := n.X.SetString(fmt.Sprintf("%g", v))
-		ctx.AddErr(errors.Promote(err, "invalid float"))
+		_, _, err := n.X.SetString(fmt.Sprint(v))
+		if err != nil {
+			return ctx.AddErr(errors.Promote(err, "invalid float"))
+		}
 		return n
 
 	case reflect.Value: