moby/buildkit: cmd/buildctl/prune.go; 13 LoC

Found a possible issue in [moby/buildkit](https://www.github.com/moby/buildkit) at [cmd/buildctl/prune.go](https://github.com/moby/buildkit/blob/5efd74b6c055e2920329f875487f4a1d6c243142/cmd/buildctl/prune.go#L57-L69)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to du was used in a composite literal at line 60

[Click here to see the code in its original context.](https://github.com/moby/buildkit/blob/5efd74b6c055e2920329f875487f4a1d6c243142/cmd/buildctl/prune.go#L57-L69)

Click here to show the 13 line(s) of Go which triggered the analyzer.

```go
for du := range ch {
total += du.Size
if clicontext.Bool("verbose") {
printVerbose(tw, []*client.UsageInfo{&du})
} else {
if first {
printTableHeader(tw)
first = false
}
printTableRow(tw, &du)
tw.Flush()
}
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 5efd74b6c055e2920329f875487f4a1d6c243142

Start with cmd/buildctl/prune.go at lines 57-69 and inspect the surrounding use of the range variable du. Determine whether the references passed to printVerbose and printTableRow can point to the wrong value under Go range-loop semantics, then leave the appropriate reaction classification on the issue.

Written by the indexing model from the issue text.