vimeo/psalm

implode(<string>, non-empty-list<string>) doesn't always result in non-empty-string

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#6,866 opened on Nov 8, 2021

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 (5 comments) (0 reactions) (0 assignees)PHP (668 forks)batch import
Help wantedbugeasy problemsgood first issueinternal stubs/callmap

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Description

https://psalm.dev/r/9b7a45c338

The weird edge case of implode('asdf', ['']); can result in an empty string. Similarly if the first argument is an empty string then an array of any amount of empty strings will also produce an empty string

Contributor guide

Research direction
Investigate how Psalm handles the return type of implode, particularly the edge case where implode with a non empty separator and an array containing an empty string returns an empty string. Examine the type inference logic and test with the provided example.
Tech stack
php
Domain
tooling
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
PHPPsalm
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70