metosin/malli

Function generators return constant function if seed provided

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#1,039 opened on Apr 16, 2024

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Description

This is because we use mg/generate to generate the return value, which always returns the same thing with the same seed.

(repeatedly 10 (mg/generate [:=> :cat :int]))
;=> (-480372 -103 7423 229 83 7937941 -4610 24 -1 21924979)
(repeatedly 10 (mg/generate [:=> :cat :int] {:seed 0}))
;=> (1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201)

;; even for different inputs
(mapv (mg/generate [:=> [:cat :int] :int] {:seed 0}) (range 10))
;=> [1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201 1784201]

Contributor guide

Research direction
Investigate the `mg/generate` function to understand why it returns a constant function when a seed is provided. Look at how the seed is used and consider modifying the generation to incorporate fresh randomness per invocation.
Tech stack
clojure
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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Active
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Clear
Prerequisites
ClojureGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70