"Goland bug", not Golang.
On Monday, September 8, 2025 at 6:10:43 PM UTC+2 TheDiveO wrote:
> There is no shadowing, this is a Golang reporting bug.
>
> On Monday, September 8, 2025 at 5:09:42 AM UTC+2 Mike Schinkel wrote:
>
>> Hi Gophers,
>>
>> I have some code that is not working as I expect it to and wanted to see
>> if I was misunderstanding something or if there is in fact a bug in the
>> compiler. I have tried this in v1.24.5 and 1.25.1.
>>
>> Here is a version of the code — heavily cut down to provide a minimal
>> example — that is not acting as I expect it to:
>>
>> func ensureRootConfig(cs cfgutil.ConfigStore) (root *RootConfigV1, err
>> error) {
>> if cs != nil {
>> root = &RootConfigV1{}
>> err = cs.LoadJSON(&root)
>> } else {
>> root = NewRootConfigV1(RootConfigV1Args{})
>> err = cs.SaveJSON(root)
>> }
>> return root, err
>> }
>>
>> When I run the above code the assignment to `root` gets shadowed and the
>> return variable is null. I have confirmed this using Goland and the Delve
>> debugger.
>>
>> The following does not shadow `root`:
>>
>> func ensureRootConfig(cs cfgutil.ConfigStore) (*RootConfigV1, error) {
>> var root *RootConfigV1
>> var err error
>> if cs != nil {
>> root = &RootConfigV1{}
>> err = cs.LoadJSON(&root)
>> } else {
>> root = NewRootConfigV1(RootConfigV1Args{})
>> err = cs.SaveJSON(root)
>> }
>> return root, err
>> }
>>
>>
>> This code, of course also works, too, but with multiple returns is not
>> the style of code we want use:
>>
>> func ensureRootConfig(cs cfgutil.ConfigStore) (*RootConfigV1, error) {
>> if cs != nil {
>> root := &RootConfigV1{}
>> err := cs.LoadJSON(&root)
>> return root, err
>> }
>> root := NewRootConfigV1(RootConfigV1Args{})
>> err := cs.SaveJSON(root)
>> return root, err
>> }
>>
>>
>> I do understand that some might want to say “just use the other
>> approaches” but if this is a bug it still needs to be reported and ideally
>> fixed given how the language should allow this, right? That is unless I
>> misunderstand something about how named return variables work with
>> shadowing.
>>
>> -Mike
>>
>>
>>
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