vimeo/psalm

implode(<non-false-string>, array) should produce non-falsy-string

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#7,055 opened on Dec 4, 2021

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Description

When the first argument is a non-falsy-string and the second argument has at least two elements, then the result is guaranteed to be at least non-falsy-string.

<?php

if(implode(' ', ['',''])) echo 1;

https://psalm.dev/r/19514cf5db

Contributor guide

Research direction
Inspect the type inference for implode() in Psalm's source code, focusing on how the return type is determined from the separator and array arguments. Look at the existing test cases for implode and add a test that demonstrates the expected non falsy string result when the separator is a non falsy string and the array has at least two elements.
Tech stack
php
Domain
developer experiencetooling
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
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PHPGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75