NoMethodError in datablock_storage#set_key_value undefined method `length' for nil:NilClass

[snickell]

https://app.honeybadger.io/projects/3240/faults/106040647/01HTAX4Z0CE2K3SAQDGZX1H837?q=request.url%3A%22%2Adatablock%2A%22

[snickell]

The issue is that in some cases (how?) students are calling set_key_value with no value param set:

  def set_key_value
    raise StudentFacingError, "The value is too large. The maximum allowable size is #{DatablockStorageKvp::MAX_VALUE_LENGTH} bytes" if params[:value].length > DatablockStorageKvp::MAX_VALUE_LENGTH
    value = JSON.parse params[:value]
    DatablockStorageKvp.set_kvp @project_id, params[:key], value

This causes the exception in the raise StudentFacingError line, which checks params[:value].length.

We tried calling set_key_value("key", undefined) (which is a legal value to pass), but this did not trigger the error.

[snickell]

Quick fix, at the start of set_key_value do:
raise StudentFacingError, "key value must be specified" if not params[:value]