Fix :map-of :min and unreachable generator, explain such-that failures #1029
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src/malli/generator.cljc
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| (gen/return (f [])) | ||
| (-never-gen options)) | ||
| (gen/fmap f (gen/vector-distinct gen {:min-elements min, :max-elements max, :max-tries 100 | ||
| :ex-fn #(ex-info (str "Could not generate enough distinct elements for schema " |
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Malli follow a "fail fast with data, pretty errors in dev-mode" philosophy. This enables both smaller bundle sizes on ClojureScript and fast runtime in prod (things like pr-str are really slow).
e.g.
(m/schema :enum)fails with just enough data, while:
((requiring-resolve 'malli.dev/start!))
(m/schema :enum)pretty prints the proper text of what happened.
Would it be possible to do same here? Currently, the malli.dev/start! hi-jacks actual throwing of error, I guess you can't control that here, just generating the exception, to be throwed by test.check?
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Thanks for the feedback.
I think it's just a matter of calling m/-exception, I'll look into it.
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Could you take another look?
| @@ -412,11 +427,21 @@ | |||
| (defmethod -schema-generator :< [schema options] (-double-gen {:max (-> schema (m/children options) first dec)})) | |||
| (defmethod -schema-generator :<= [schema options] (-double-gen {:max (-> schema (m/children options) first)})) | |||
| (defmethod -schema-generator := [schema options] (gen/return (first (m/children schema options)))) | |||
| (defmethod -schema-generator :not= [schema options] (gen/such-that #(not= % (-> schema (m/children options) first)) gen/any-printable 100)) | |||
| (defmethod -schema-generator :not= [schema options] (gen/such-that #(not= % (-> schema (m/children options) first)) gen/any-printable | |||
| {:max-tries 100 | |||
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some of these have :max-tries, but not all, is there a reason for this?
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My best guess is that the ones without :max-tries always succeed in practice.
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Thanks! Calling the |
The
:map-ofgenerator should use(gen/vector-distinct-by first ..)in order to satisfy:min, otherwise it can generate less than the minimum number of entries by generating the same key multiple times with different vals.such-thatand functions built on it accept a custom error message on generation failures. It's very helpful to have the precise schema that failed in the error message.The unreachable elements case for
:map-ofdisallows generating the empty map if:maxwas non-zero. It's perfectly fine to generate empty regardless of:max. Other collection generators almost made this mistake by checking(<= (or min 0) 0 (or max 0)), which is technically correct but simplifiable to(= 0 (or min 0)).coll-distinct-gennested generators incorrectly in the unreachable elements case. We want(-never-gen options), not(gen/fmap f (-never-gen options))which defeats our simplification logic of checking for-never-gen's metadata.