always_use_return and short_circuit_to_if` bug

[edward-bestx]

I think I have found a bug which I think is related to the combination of two settings:

always_use_return = true
short_circuit_to_if = true

Here is some example code which I subsequently ran the formatter on.

cat ExampleModule2.jl
module ExampleModule2

function __init__()
    global LOGFILEHANDLE = "notset"
    return nothing
end

function write(logfilehandle, something)
    println("writing $(something) to logfilehandle=$(logfilehandle)")
    return 10
end

function exampleFunction()
    LOGFILEHANDLE != "notset" && write(LOGFILEHANDLE, "examplestring")
end

function whatDoesExampleFunctionReturn()
    tmp = exampleFunction()
    println("type: $(typeof(tmp))")
    println(tmp)
end

end

And here is the result of the format. I change the function names so that you can combine both of these into a single Julia file, if you wish to do so.

cat ExampleModule2.jl
module ExampleModule2

function __init__()
    global LOGFILEHANDLE = "notset"
    return nothing
end

function write(logfilehandle, something)
    println("writing $(something) to logfilehandle=$(logfilehandle)")
    return 10
end

function exampleFunction2()
    return if LOGFILEHANDLE != "notset"
        write(LOGFILEHANDLE, "examplestring")
    end
end

function whatDoesExampleFunction2Return()
    tmp = exampleFunction2()
    println("type: $(typeof(tmp))")
    println(tmp)
end

end

Here's the result of running both, combined into a single file ExampleModule2.jl:

julia> using ExampleModule2
[ Info: Precompiling ExampleModule2 [top-level] (cache misses: include_dependency fsize change (2))

julia> ExampleModule2.whatDoesExampleFunctionReturn()
type: Bool
false

julia> ExampleModule2.whatDoesExampleFunction2Return()
type: Nothing
nothing

julia> ExampleModule2.LOGFILEHANDLE = "set"
"set"

julia> ExampleModule2.whatDoesExampleFunctionReturn()
writing examplestring to logfilehandle=set
type: Int64
10

julia> ExampleModule2.whatDoesExampleFunction2Return()
writing examplestring to logfilehandle=set
type: Int64
10

What is important to note is that the formatter changes the behavior of exampleFunction.

• When LOGFILEHANDLE = "notset", exampleFunction returns false.
• After formatting, exampleFunction2 returns nothing instead of false.

Hopefully that is clear?

Maybe the formatter should do this instead?

function exampleFunction2()
    return (
        if LOGFILEHANDLE != "notset"
            write(LOGFILEHANDLE, "examplestring")
        else
            false
        end
    )
end

It's actually kind of hard to say what it should do with

LOGFILEHANDLE != "notset" && write(LOGFILEHANDLE, "examplestring")

because this isn't really a very sensible piece of code. But it does return false if the first condition is false and then it returns the return value of write otherwise.