json and 'omitempty'

[Alexander Sychev]

Hello!

I have found an unexpected by me behaviour of the 'omitempty' option in

the json package.

http://play.golang.org/p/Flz8unbXnF

The field SomeA of the structure B is the structure with unexported

fields, so SomeA can't be marshaled to JSON. The SomeA has the option

'omitempty' and I expect the SomeA won't appear in resulting JSON. But it

does appear.

This is a bug? Or a feature?

-- 

Best regards,

    santucco

[roger peppe]

i think this is within spec. the docs say:
"The empty values are false, 0, any nil pointer or interface value,
and any array, slice, map, or string of length zero"

that doesn't include structs, so i think the above behaviour is correct.

it could be argued that a zero-valued struct should be considered empty,
especially now that structs are comparable. but that would be an API change.

for the time being, you could use *A instead of A.

[Alexander Sychev]

Thanks!

Actually I found this in GAE, where new option 'omit' is not yet
presented, so I have hoped 'omitempty' for such case can help.

--
Best regards,

Alexander Sychev
Senior Developer
Kaspersky Lab

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