Clojure : “java.lang.IllegalArgumentException: No value supplied for key:” when I changed require

Question

I'm getting a java.lang.IllegalArgumentException: No value supplied for key: in my Clojure code.

I know this is what happens when I'm trying to destructure the keys in a mapping passed as an argument.

However, what's odd here is that this function has been working fine for ages, with the same data. And the only thing that seems to be different is how I'm now importing the function

Here's the error:

Caused by: java.lang.IllegalArgumentException: No value supplied for key: 
{:style {:color [255 150 150 255], :stroke-weight 2}, :points [[-1 0] [0 -1] [1 0] [0 1] [-1 0]]}

And here's the function that threw it.

(defn scale
  [val {:keys [style points]}]
  {:style style
   :points (scale-shape val points)})

In other words, I'm asking for the map to contain keys called style and points and it's being given a map which contains keys called style and points.

And this code has been working fine for months.

The difference is that I'm now calling it using sshapes/scale where sshapes was imported with:

 (:require [patterning.sshapes :as sshapes])

whereas previously I was just calling it as scale where scale came into the namespace using

 (:require [patterning.sshapes :refer :all])

Could this cause that kind of error?

Is it possible that :refer :all was pulling in another function that you were using before? (For example, what about scale-shapes?) Now that this other function not being pulled in, maybe you're using a function of the same name from a different namespace, and it's not generating something in the format that sshapes/scale expects. — Mars
Good thought. It can't be exactly that, but it's possible in my rewriting I have mixed up a call to the lower-level scale-shapes and this scale function. Though it's weird because the error message seems to imply I'm sending a map with the right keys. — interstar
The code you have provided is not enough to figure out what's going on - the exception is coming from somewhere else in your program, probably in whatever function calls scale. Please include the relevant code or at least a full stacktrace, if you need help debugging an error message. — amalloy
Got a snippet we can run that reliably reproduces that error? — Brad Koch

interstar interstar · Accepted Answer · 2014-07-08T19:27:00

OK. I changed the code to use

(:require [patterning.sshapes :refer [scale rotate]])

ie. with the required functions named explicitly, did a lein clean, and the problem has disappeared. The function definitions themselves and the code which calls them remain the same.

Weird.

Clojure : “java.lang.IllegalArgumentException: No value supplied for key:” when I changed require

1 Answers