Trailing comma gets removed if there is only one parameter and it is formatted to be on its own line

[hongping-quora]

Using the ktfmt IntelliJ plugin 1.1.0.47 in Android Studio, setting "Code style" to "Google (internal)"

1. The following code with a single parameter will get the trailing comma removed.

import android.content.SharedPreferences

private class AllowlistedDiskReadsSharedPreferences(
  private val wrappedPreferences: SharedPreferences,
) : SharedPreferences by wrappedPreferences

2. This code with two parameters will not.

import android.content.SharedPreferences

private class AllowlistedDiskReadsSharedPreferences(
  private val wrappedPreferences: SharedPreferences,
  private val wrappedPreferences2: SharedPreferences,
) : SharedPreferences by wrappedPreferences 

Since one of the reasons of using trailing comma is to avoid having to modify an existing line when adding another parameter (https://kotlinlang.org/docs/coding-conventions.html#trailing-commas), perhaps even when there is only one parameter but it has to be on its own line, it should also have a trailing comma?

Thanks!

[hick209]

@nreid260, do you think this is a bug or within your expectations?

[nreid260]

This is working as intended, at least for now. The Google Kotlin style committee preferred that single-element lists never got trailing commas. However, there's no technical reason to do this, only aesthetic, so they could be convinced otherwise.

One technical constraint was that I explicitly wanted to remove the "hinting" behaviour or trailing commas. --google-style totally manages trailing commas, based on the rest of the code. If you really want to force a line-break, // is still available.