r\branch Expected type DATUM but found FUNCTION

[wojons]

I found this in one of my large MR queries., I will attach the fix i used to a pull request.

[danielmewes]

Thanks for the report and patch @wojons.
According to the query language definition (https://github.com/rethinkdb/rethinkdb/blob/next/src/rdb_protocol/ql2.proto) r\branch can take a function. But it might be wrong. I'll investigate that.

Was one of the arguments to r\branch() actually a function when you encountered this issue or was it triggered by a non-function argument?

[danielmewes]

In the Data Explorer I can actually do something like

r.expr([1, 2, 3]).map(r.branch(r.expr(true), function(x) {return x;}, function(x) {return x;}))

and even

r.expr([1, 2, 3]).map(r.branch(r.expr(true), function(x) {return x;}, 1))

(i.e. mix function and datum arguments in the same r.branch)

@wojons: What are the arguments to branch for which you saw this error? (if they are not too long)

[danielmewes]

Never mind @wojons, I can reproduce it with this query in PHP:

r\expr(array(1,2,3))->map(r\branch(r\expr(true), function ($x) { return $x; }, function ($x) { return $x; }))

[danielmewes]

The problem here is actually map wrapping a dummy function around the branch.

[danielmewes]

@wojons: I just released PHP-RQL 1.12.2 with a fix. It was slightly more complex than what you did, because not supporting functions in r\branch() would have caused other regressions (see df53f81 for the actual changes made).