Every time format, a comma is added.

[Coordinate-Cat]

What version of CUE are you using (cue version)?

$ cue version v0.4.2 darwin/amd64

Does this issue reproduce with the latest release?

yes

What did you do?

At first I thought it was a formatting bug in the vscode extension, but it seems to be reproduced in cue fmt, so I'm reporting it.
johnallen3d/vscode-cue-fmt#8

What did you expect to see?

What did you see instead?

I don't want commas to be added after formatting.

❯ cat test.cue
test: {
	test_list: {
		test_list_arr: [
			{
				name: "hoge"
			},
			{
				name: "fuga"
			},
		]
		// list: [
		//   {
		//     name: "hoge"
		//   }
		// ]
	}
	test_list2: {
		create: [
			{}
			// {
			//   name: "hoge"
			// },
			// {
			//   name: "fuga"
			// },
		]
	}
}

❯ cue fmt test.cue 

❯ cat test.cue
test: {
	test_list: {
		test_list_arr: [
			{
				name: "hoge"
			},
			{
				name: "fuga"
			},
		]
		// list: [
		//   {
		//     name: "hoge"
		//   }
		// ]
	}
	test_list2: {
		create: [
			{}                        <-------- Removing this object will fix it, but I don't want to remove it.
			// {
			//   name: "hoge"
			// },
			// {
			//   name: "fuga"
			// },,,,,,                <------- this
		]
	}
}

[rogpeppe]

Here's a simple testscript reproducer:

exec cue fmt x.cue
cp x.cue x1.cue
exec cue fmt x.cue
cmp x.cue x1.cue

-- x.cue --
[
	{} //
]

This fails for me as follows:

> exec cue fmt x.cue
> cp x.cue x1.cue
> exec cue fmt x.cue
> cmp x.cue x1.cue
--- x.cue
+++ x1.cue
@@ -1,3 +1,3 @@
 [
-	{} //,,
+	{} //,
 ]

FAIL: /tmp/testscript108976944/x.txtar/script.txt:4: x.cue and x1.cue differ
error running /tmp/x.txtar in /tmp/testscript108976944/x.txtar

testscript: exit 1

[mvdan]

I am pretty sure that this is a duplicate of #1478, which is a bit older and has been correctly labelled for some time as well.