`:via` is empty when instrumentation fails on `:ret` spec

[bhb]

Using [orchestra "2017.07.04-1"]

My environment is a lein REPL: lein repl.

(require '[orchestra.spec.test :as st1])

(s/def :example/age pos-int?)
(s/fdef foobar
        :args (s/cat :x :example/age)
        :ret :example/age)
(defn foobar [x] -10)
(st1/instrument `foobar)
;; Try an instrumentation failure for `:args`
(foobar -1)
;; Prints failure message including this `explain-data`:
;; {:clojure.spec.alpha/problems [{:path [:args :x], :pred clojure.core/pos-int?, :val -1, :via [:example/age :example/age], :in [0]}], :clojure.spec.alpha/spec #object[clojure.spec.alpha$regex_spec_impl$reify__1200 0xac00133 "clojure.spec.alpha$regex_spec_impl$reify__1200@ac00133"], :clojure.spec.alpha/value (-1), :clojure.spec.alpha/args (-1), :clojure.spec.alpha/failure :instrument, :orchestra.spec.test/caller {:file "form-init5213886586620856240.clj", :line 256, :var-scope expound.alpha/eval36771}}
;; Note the 

;; Try an instrumentation failure for `:ret`
(foobar 10)
;; Prints failure message including this `explain-data`:
;; {:clojure.spec.alpha/problems [{:path [:ret], :pred clojure.core/pos-int?, :val -10, :via [], :in []}], :clojure.spec.alpha/spec #object[clojure.spec.alpha$spec_impl$reify__751 0x2c9a79fd "clojure.spec.alpha$spec_impl$reify__751@2c9a79fd"], :clojure.spec.alpha/value -10, :clojure.spec.alpha/ret -10, :clojure.spec.alpha/failure :instrument, :orchestra.spec.test/caller {:file "form-init5213886586620856240.clj", :line 259, :var-scope expound.alpha/eval36773}}

Expected: The :via value should be populated (namely, it should include [:example/age :example/age].

[jeaye]

Hm, I'm not sure what :via actually represents, but I think it's certainly an inconsistency between :args and the :ret and :fn which orchestra add; good find!

I'll get this fixed.

[jeaye]

When I look at the instrumentation source, there's no trace of :via, so this must be coming from higher up in clojure.spec, meaning outside the instrumentation code.

This is only after a cursor search, and I'm not yet certain of the meaning of :via, but it looks like either this needs to be addressed in clojure.spec or it needs to be subsequently accounted for in orchestra.

[bhb]

AIUI, :via is the set of specs that were followed to get to the failing predicate.

For example, note the following three spec failures. All three have the same predicate since 123 is not a string, but they arrive at that predicate via different specs:

(require '[clojure.spec.alpha :as s])

(s/def :example/name string?)
(s/def :example/person (s/keys :req-un [:example/name]))

(-> (s/explain-data string? 123) ::s/problems first (select-keys [:via :pred]))
;; {:via [], :pred :clojure.spec.alpha/unknown}
;; I'm actually not 100% sure why the above is unknown

(-> (s/explain-data :example/name 123) ::s/problems first (select-keys [:via :pred]))
;; {:via [:example/name], :pred clojure.core/string?}

(-> (s/explain-data :example/person {:name 123}) ::s/problems first (select-keys [:via :pred]))
;; {:via [:example/person :example/name], :pred clojure.core/string?}

[jeaye]

Thanks a great explanation of :via, thank you. I've found the cause of the empty :via in orchestra to be here: https://github.com/jeaye/orchestra/blob/master/src/clj/orchestra/spec/test.clj#L102 Looks like s/explain-data* is expecting [spec path via in x].

I'll work to get a fix for this in the next few days.

[jeaye]

I've pushed a fix for this and I've tested this new orchestra version with your expound snapshot as well. The only thing missing is the "relevant specs" section on :ret failures, which should now be possible.

Please let me know if you have any more troubles with this. Thanks for the help!

[bhb]

@jeaye It works great! Thank for the quick fix.