JSON serialization assumes Maps aren't iterable

[mikekap]

I'm using the java libraries from Clojure. Clojure native types (maps, vectors, etc) follow all normal java interfaces, except the built-in maps implement Iterable. When using these with BigQuery streaming, the JSON serializer thinks these are collections rather than maps and serializes them incorrectly. It would be nice if it didn't make that assumption and just directly checked for a x instanceof Map.

[garrettjonesgoogle]

• Is the following an accurate way of describing the issue?: "JSON serialization doesn't check to see if Iterables are Maps"
• Is this considered to be a flaw of Clojure that is going to be fixed, or is it permanently baked in?

[garrettjonesgoogle]

No response from filer, so closing this out. Please re-open if you still need a resolution to this problem.

[lvh]

Hi! I filed an identical issue here: #2432 .

It is definitely not a flaw of Clojure's builtin maps, they are simply both Iterable (producing their pairs) and java.util.Map; so Clojure won't be fixing that.

I have a totally gross workaround that creates a proxy type: an object that holds the object implementing multiple interfaces and instead exposing only one. It's awful but it works. I've added a link to that code to the other ticket. Still a very nasty surprise for people using the SDK from Clojure.

[mikekap]

@garrettjonesgoogle Sorry I missed the request for information. To answer:

• Yes - "JSON serialization doesn't check to see if Iterables are Maps" is a valid way of describing the issue.
• This is not considered a flaw in Clojure. It's arguable whether a Map should be iterable or not, Java certainly doesn't prevent you from doing so. Unfortunately even if we all agreed that a Map shouldn't be iterable, it's infeasible at this point to change Clojure maps - a lot of libraries assume maps are iterable as entries.