NullPointerException when a >defn calls another >defn with invalid arguments

[whmountains]

I accidentally hit enter before I was ready, so apologies to anyone who may have gotten a confusing email notification.

I am getting a NullPointerException related to clojure.string/split-lines when a >defn is being generatively tested, and calls another function with arguments that don't match the spec. I find myself constantly hitting this. Instead of a concise error message I get pages and pages of nested stack traces.

Here is my minimal reproduction.

(>defn inner
       [input]
       [int? => string?]
       (str input))

(>defn outer
       [input]
       [string? => string?]
       (inner input))

(g/check)

It appears the error is coming from line 180 in reporting.cljc. Here is a snippet of the stack trace:

{:file "Matcher.java",
 :line 1770,
 :type :error,
 :expected
 (clojure.core/and
  (clojure.core/every?
   (fn*
    [p1__2441__2443__auto__]
    (clojure.core/->
     p1__2441__2443__auto__
     :clojure.spec.test.check/ret
     :pass?))
   spec-checks__2442__auto__)
  true
  true),
 :actual #error {
 :cause nil
 :via
 [{:type java.lang.NullPointerException
   :message nil
   :at [java.util.regex.Matcher getTextLength "Matcher.java" 1770]}]
 :trace
 [[java.util.regex.Matcher getTextLength "Matcher.java" 1770]
  [java.util.regex.Matcher reset "Matcher.java" 416]
  [java.util.regex.Matcher <init> "Matcher.java" 253]
  [java.util.regex.Pattern matcher "Pattern.java" 1135]
  [java.util.regex.Pattern split "Pattern.java" 1263]
  [java.util.regex.Pattern split "Pattern.java" 1336]
  [clojure.string$split invokeStatic "string.clj" 224]
  [clojure.string$split_lines invokeStatic "string.clj" 228]
  [clojure.string$split_lines invoke "string.clj" 228]
  [ghostwheel.reporting$report_spec_check invokeStatic "reporting.c
ljc" 180]
  [ghostwheel.reporting$report_spec_check invoke "reporting.cljc" 163]
  [ghostwheel.reporting$eval2004$fn__2005 invoke "reporting.cljc" 208]
  [clojure.lang.MultiFn invoke "MultiFn.java" 229]
  [clojure.test$do_report invokeStatic "test.clj" 357]
  [clojure.test$do_report invoke "test.clj" 351]
  [ghostwheel_repr.core$fn__11380 invokeStatic "core.clj" 12]
;; stack trace continues into clojure internals...
]
;; other properties elided
}

[gnl]

Project update July 2023: DO NOT PANIC – this is not a eulogy