ravivooda/gofor

Go For Range Copy checks if code uses range assigned variable for editing purposes

Go For - Range Copy - Editing

A GoLand plugin to help developers detect an edge case: editing a range assigned variable.

Motivation

Go dictates range clause to copy collection before iterating.

Consider the following go code

package main
import "fmt"
type Editable struct{ i int }

func pumpUp(e *Editable)  {
 e.i = 100
}

func main() {
 es := []Editable { { i : 1 }, { i : 2 }, { i : 3 }, { i : 4 } }
 for _, e := range es {
 	pumpUp(&e)
 }
 fmt.Printf("%v", es)
}

below outlines the output in Go, Swift, Objective-C, Java (keeping the semantics same)

Language	Output
Go	[{1} {2} {3} {4}]
Swift	[{100} {100} {100} {100}]
Java	[{100} {100} {100} {100}]
Objective-C	[{100} {100} {100} {100}]

This plugin tries to catch such use cases and highlight them for the developer to reconsider the logic

Supported

1. Detect usages of pointer references of assigned variable in a for block
2. Detect editable method references of assigned variable in the block

To be supported

1. Assigned variable is predeclared before the range clause
2. Direct assignment of the struct's properties

* please see issues for more

Output

References

Assigned Variable = e in the above go for block

Gradle Scan: https://scans.gradle.com/s/vywyvtekrzqfg

Reference: Plugin Extension Points in IntelliJ SDK Docs

gofor's Issues

Remove debug logs from the project

Specifically, need to remove 'PsiViewer:201.6251.22-EAP-SNAPSHOT.1' from the build.Gradle file. This is only needed for my debugging purposes