saveourtool/diktat

[`INVERSE_FUNCTION_PREFERRED`] should not replace `!ClosedRange.isEmpty()`

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#1,699 opened on Jun 22, 2023

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buggood first issue

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Description

Describe the bug

Given the following code:

val range: ClosedRange<Int> = 0..1
check(!range.isEmpty())

Diktat suggests replacing this with the nonexistent ClosedRange.isNotEmpty() function:

[INVERSE_FUNCTION_PREFERRED] it is better to use inverse function: isNotEmpty() instead of !isEmpty() (diktat-ruleset:inverse-method)

Expected behavior

Rule should not be triggered when the isNotEmpty function does not exist.

Environment information

  • diktat version: 1.2.5
  • how is diktat run (CLI, plugin, etc.): CLI

Contributor guide

Research direction
Investigate the INVERSE FUNCTION PREFERRED rule implementation to add a check that the suggested inverse function (e.g., isNotEmpty()) actually exists in the standard library before triggering the warning.
Tech stack
kotlin
Domain
devtools
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.
Under 1 hour
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
Kotlin
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70