NIL is not of type CHARACTER (w/ commit b5ae82b)

[cdmojoli]

Commit b5ae82b modifies the creation of request objects introducing add-query-with-input, which effectively changes the type of the :path slot from string to QURI.URI:URI.

This triggers an error inside QURI::MAYBE-SLASH, where (char/= (uiop:first-char path) #\/) expects a char but instead gets (UIOP:FIRST-CHAR path) → nil.

To illustrate:

The value
  NIL
is not of type
  CHARACTER
BREAK was entered because of *BREAK-ON-SIGNALS* (now rebound to NIL).
   [Condition of type SIMPLE-CONDITION]

...

Backtrace:
 0: ((FLET QURI::MAYBE-SLASH :IN QURI:RENDER-URI) "dynamodb.us-east-1.amazonaws.com" #<QURI.URI:URI />)
 1: (QURI:RENDER-URI #<error printing URI-HTTPS {1005B00573}> NIL)
 2: (AWS-SDK/API:AWS-REQUEST #<AWS-SDK/SERVICES/DYNAMODB/API:DYNAMODB-REQUEST {1005927583}> :WANT-STREAM NIL)
 3: (AWS-SDK/SERVICES/DYNAMODB/API:GET-ITEM :RETURN-CONSUMED-CAPACITY "TOTAL" :TABLE-NAME "*****" :KEY #<HASH-TABLE :TEST EQL :COUNT 1 {1005ACA3C3}>)

Just changing the result type of add-query-with-input to string should solve this, but I do not know the programmer's intent here, so it's just a suggestion.