Fix ordering issue in formatter (#1289)

Author: stackoverflow

docs/modules/release-notes/pages/0.30.adoc

@@ -25,7 +25,7 @@ To get started, follow xref:pkl-cli:index.adoc#installation[Installation].#
 [[formatter]]
 === Formatter
 
-Pkl now has a formatter (https://github.com/apple/pkl/pull/1107[#1107], https://github.com/apple/pkl/pull/1208[#1208], https://github.com/apple/pkl/pull/1211[#1211], https://github.com/apple/pkl/pull/1215[#1215], https://github.com/apple/pkl/pull/1217[#1217], https://github.com/apple/pkl/pull/1235[#1235], https://github.com/apple/pkl/pull/1246[#1246], https://github.com/apple/pkl/pull/1247[#1247], https://github.com/apple/pkl/pull/1252[#1252], https://github.com/apple/pkl/pull/1256[#1256], https://github.com/apple/pkl/pull/1259[#1259], https://github.com/apple/pkl/pull/1260[#1260], https://github.com/apple/pkl/pull/1263[#1263], https://github.com/apple/pkl/pull/1265[#1265], https://github.com/apple/pkl/pull/1266[#1266], https://github.com/apple/pkl/pull/1267[#1267], https://github.com/apple/pkl/pull/1268[#1268], https://github.com/apple/pkl/pull/1270[#1270], https://github.com/apple/pkl/pull/1271[#1271], https://github.com/apple/pkl/pull/1272[#1272], https://github.com/apple/pkl/pull/1273[#1273], https://github.com/apple/pkl/pull/1274[#1274], https://github.com/apple/pkl/pull/1280[#1280])!
+Pkl now has a formatter (https://github.com/apple/pkl/pull/1107[#1107], https://github.com/apple/pkl/pull/1208[#1208], https://github.com/apple/pkl/pull/1211[#1211], https://github.com/apple/pkl/pull/1215[#1215], https://github.com/apple/pkl/pull/1217[#1217], https://github.com/apple/pkl/pull/1235[#1235], https://github.com/apple/pkl/pull/1246[#1246], https://github.com/apple/pkl/pull/1247[#1247], https://github.com/apple/pkl/pull/1252[#1252], https://github.com/apple/pkl/pull/1256[#1256], https://github.com/apple/pkl/pull/1259[#1259], https://github.com/apple/pkl/pull/1260[#1260], https://github.com/apple/pkl/pull/1263[#1263], https://github.com/apple/pkl/pull/1265[#1265], https://github.com/apple/pkl/pull/1266[#1266], https://github.com/apple/pkl/pull/1267[#1267], https://github.com/apple/pkl/pull/1268[#1268], https://github.com/apple/pkl/pull/1270[#1270], https://github.com/apple/pkl/pull/1271[#1271], https://github.com/apple/pkl/pull/1272[#1272], https://github.com/apple/pkl/pull/1273[#1273], https://github.com/apple/pkl/pull/1274[#1274], https://github.com/apple/pkl/pull/1280[#1280], https://github.com/apple/pkl/pull/1283[#1283], https://github.com/apple/pkl/pull/1289[#1289], https://github.com/apple/pkl/pull/1290[#1290])!
 
 Pkl's formatter is _canonical_, which means that it has a single set of formatting rules, with (almost) no configuration options.
 The goal is to eliminate the possibility of formatting debates, which can lead to churn and bike-shedding.

pkl-formatter/src/main/kotlin/org/pkl/formatter/Builder.kt

@@ -36,12 +36,10 @@ import org.pkl.parser.syntax.generic.NodeType
 internal class Builder(sourceText: String, private val grammarVersion: GrammarVersion) {
   private var id: Int = 0
   private val source: CharArray = sourceText.toCharArray()
-  private var prevNode: Node? = null
   private var noNewlines = false
 
-  fun format(node: Node): FormatNode {
-    prevNode = node
-    return when (node.type) {
+  fun format(node: Node): FormatNode =
+    when (node.type) {
       NodeType.MODULE -> formatModule(node)
       NodeType.DOC_COMMENT -> Nodes(formatGeneric(node.children, null))
       NodeType.DOC_COMMENT_LINE -> formatDocComment(node)
@@ -164,7 +162,6 @@ internal class Builder(sourceText: String, private val grammarVersion: GrammarVe
       NodeType.PARENTHESIZED_TYPE_ELEMENTS -> formatParenthesizedTypeElements(node)
       else -> throw RuntimeException("Unknown node type: ${node.type}")
     }
-  }
 
   private fun formatModule(node: Node): FormatNode {
     val nodes =
@@ -617,6 +614,7 @@ internal class Builder(sourceText: String, private val grammarVersion: GrammarVe
       val trailingNode = if (endsWithClosingCurlyBrace(lastParam.last())) Empty else line()
       val lastNodes = formatGenericWithGen(lastParam, sep, null)
       if (normalParams.isEmpty()) {
+        val lastNodes = formatGenericWithGen(lastParam, sep, null)
         group(Group(newId(), lastNodes), trailingNode)
       } else {
         val separator = getSeparator(normalParams.last(), lastParam[0], Space)
@@ -1289,7 +1287,7 @@ internal class Builder(sourceText: String, private val grammarVersion: GrammarVe
 
   private fun getBaseSeparator(prev: Node, next: Node): FormatNode? {
     return when {
-      prevNode?.type == NodeType.LINE_COMMENT -> {
+      endsInLineComment(prev) -> {
         if (prev.linesBetween(next) > 1) {
           TWO_NEWLINES
         } else {
@@ -1325,6 +1323,14 @@ internal class Builder(sourceText: String, private val grammarVersion: GrammarVe
     }
   }
 
+  private tailrec fun endsInLineComment(node: Node): Boolean {
+    return when {
+      node.type == NodeType.LINE_COMMENT -> true
+      node.children.isEmpty() -> false
+      else -> endsInLineComment(node.children.last())
+    }
+  }
+
   private fun line(): FormatNode {
     return if (noNewlines) Empty else Line
   }