Error on all .kt files: "TypeError: Cannot read property 'toString' of null"

[zrev2220]

Background

In a project of mine, I recently converted some Java files to Kotlin and installed this plugin to format them. When I next ran prettier, though, this bug appeared. To ensure it wasn't something weird with my project specifically, I created a blank project to reproduce the issue. Below are the steps to reproduce the bug.

Reproduction steps

1. Create a blank npm project

   npm init
   

2. Install prettier and prettier-plugin-kotlin

   npm i prettier prettier-plugin-kotlin
   

3. Create a sample Kotlin file to format, named example.kt (I used the one below from "Example 1" at https://www.tutorialkart.com/kotlin/kotlin-create-file/)

   import java.io.File
   
   fun main(args: Array<String>) {
   
       val fileName = "data.txt"
   
       var file = File(fileName)
   
       // create a new file
       val isNewFileCreated :Boolean = file.createNewFile()
   
       if(isNewFileCreated){
           println("$fileName is created successfully.")
       } else{
           println("$fileName already exists.")
       }
   
       // try creating a file that already exists
       val isFileCreated :Boolean = file.createNewFile()
   
       if(isFileCreated){
           println("$fileName is created successfully.")
       } else{
           println("$fileName already exists.")
       }
   
   }
   

4. Run prettier

   npx prettier --write *
   

Expected behavior

The three files in the project at the moment (package.json, package-lock.json, and example.kt) should be formatted correctly and the command should exit with code 0.

Actual behavior

example.kt is not formatted. The command exits with code 2.

The following output is produced:

$ npx prettier --write *
example.kt
[error] example.kt: TypeError: Cannot read property 'toString' of null
[error]     at Object.module.exports [as parse] (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier-plugin-kotlin\src\parse.js:13:30)
[error]     at Object.parse$a [as parse] (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\index.js:14892:19)
[error]     at coreFormat (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\index.js:16425:16)
[error]     at formatWithCursor$1 (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\index.js:16665:14)
[error]     at Object.formatWithCursor (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\index.js:60922:12)
[error]     at format$1 (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\bin-prettier.js:16107:14)
[error]     at Object.formatFiles$1 [as formatFiles] (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\bin-prettier.js:16218:16)
[error]     at main (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\bin-prettier.js:17989:10)
[error]     at Object.run (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\bin-prettier.js:17932:5)
[error]     at Object.<anonymous> (<REDACTED>\prettier-plugin-kotlin-bug\node_modules\prettier\bin-prettier.js:18000:20)
package.json 23ms
package-lock.json 18ms

Other remarks

The same error will be logged for all Kotlin files Prettier tries to format.

Looks like this line is a place to start looking:

https://github.com/Angry-Potato/prettier-plugin-kotlin/blob/7572ee3d19cea470ec427a79903b23905a8d1677/src/parse.js#L13

I guess child.stderr is null in my case? Not sure if that's a shell issue for me specifically, or if anyone else is having the same problem.

[zrev2220]

Any update on this issue? I have to uninstall prettier-plugin-kotlin and not auto-format *.kt files at all in the meantime.