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Pass nil slice when variadic arguments are omitted after regular args. #1150

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Merged
merged 1 commit into from
Sep 18, 2022
Merged

Pass nil slice when variadic arguments are omitted after regular args. #1150

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11 changes: 9 additions & 2 deletions compiler/utils.go
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Original file line number Diff line number Diff line change
Expand Up @@ -140,8 +140,15 @@ func (fc *funcContext) translateArgs(sig *types.Signature, argExprs []ast.Expr,
// If variadic arguments were passed in as individual elements, regroup them
// into a slice and pass it as a single argument.
if sig.Variadic() && !ellipsis {
return append(args[:sigTypes.RequiredParams()],
fmt.Sprintf("new %s([%s])", fc.typeName(sigTypes.VariadicType()), strings.Join(args[sigTypes.RequiredParams():], ", ")))
required := args[:sigTypes.RequiredParams()]
var variadic string
if len(args) == sigTypes.RequiredParams() {
// If no variadic parameters were passed, the slice value defaults to nil.
variadic = fmt.Sprintf("%s.nil", fc.typeName(sigTypes.VariadicType()))
} else {
variadic = fmt.Sprintf("new %s([%s])", fc.typeName(sigTypes.VariadicType()), strings.Join(args[sigTypes.RequiredParams():], ", "))
}
return append(required, variadic)
}
return args
}
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57 changes: 41 additions & 16 deletions tests/compiler_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,25 +5,50 @@ import (
)

func TestVariadicNil(t *testing.T) {
printVari := func(strs ...string) []string {
return strs
}
t.Run("only variadic", func(t *testing.T) {
printVari := func(strs ...string) []string {
return strs
}

if got := printVari(); got != nil {
t.Errorf("printVari(): got: %#v; want %#v.", got, nil)
}

{
var want []string
if got := printVari(want...); got != nil {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, nil)
}
}

if got := printVari(); got != nil {
t.Errorf("printVari(): got: %#v; want %#v.", got, nil)
}
{
want := []string{}
if got := printVari(want...); got == nil || len(got) != len(want) {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, want)
}
}
})
t.Run("mixed", func(t *testing.T) {
printVari := func(_ int, strs ...string) []string {
return strs
}

if got := printVari(0); got != nil {
t.Errorf("printVari(): got: %#v; want %#v.", got, nil)
}

{
var want []string
if got := printVari(want...); got != nil {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, nil)
{
var want []string
if got := printVari(0, want...); got != nil {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, nil)
}
}
}

{
want := []string{}
if got := printVari(want...); got == nil || len(got) != len(want) {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, want)
{
want := []string{}
if got := printVari(0, want...); got == nil || len(got) != len(want) {
t.Errorf("printVari(want...): got: %#v; want %#v.", got, want)
}
}
}
})
}