Correctly parse stream signatures (#26659) (#26669)

That were spread over multiple lines since switching to scalafmt

project/ParadoxSupport.scala

@@ -13,6 +13,7 @@ import org.pegdown.ast._
 import sbt.Keys._
 import sbt._
 
+import scala.annotation.tailrec
 import scala.io.{Codec, Source}
 import scala.collection.JavaConverters._
 
@@ -52,9 +53,9 @@ object ParadoxSupport {
           } else new File(page.file.getParentFile, source)
 
         val Signature = """\s*((def|val|type) (\w+)(?=[:(\[]).*)(\s+\=.*)""".r // stupid approximation to match a signature
-        //println(s"Looking for signature regex '$Signature'")
+
         val text =
-          Source.fromFile(file)(Codec.UTF8).getLines.collect {
+          getDefs(file).collect {
             case line@Signature(signature, kind, l, definition) if labels contains l.replaceAll("Mat$", "").toLowerCase() =>
               //println(s"Found label '$l' with sig '$full' in line $line")
               if (kind == "type") signature + definition
@@ -62,11 +63,9 @@ object ParadoxSupport {
           }.mkString("\n")
 
         if (text.trim.isEmpty) {
-          logWarn(
+          throw new IllegalArgumentException(
-            s"Did not find any signatures with one of those names [${labels.mkString(", ")}] in ${node.source} " +
+            s"Did not find any signatures with one of those names [${labels.mkString(", ")}] in $source " +
             s"(was referenced from [${page.path}])")
-
-          new HtmlBlockNode(s"""<div style="color: red;">[Broken signature inclusion [${labels.mkString(", ")}] to [${node.source}]</div>""").accept(visitor)
         } else {
           val lang = Option(node.attributes.value("type")).getOrElse(Snippet.language(file))
           new VerbatimNode(text, lang).accept(visitor)
@@ -77,4 +76,19 @@ object ParadoxSupport {
       }
   }
 
+  def getDefs(file: File): Seq[String] = {
+    val Indented = "(\\s*)(.*)".r
+
+    @tailrec
+    def rec(lines: Iterator[String], currentDef: Option[String], defIndent: Integer, soFar: Seq[String]): Seq[String] = {
+      if (!lines.hasNext) soFar ++ currentDef
+      else lines.next() match {
+        case Indented(indent, line) =>
+          if (line.startsWith("def")) rec(lines, Some(line), indent.length, soFar ++ currentDef)
+          else if (indent.length == defIndent + 4) rec(lines, currentDef.map(_ ++ line), defIndent, soFar)
+          else rec(lines, None, 0, soFar ++ currentDef)
+      }
+    }
+    rec(Source.fromFile(file)(Codec.UTF8).getLines, None, 0, Nil)
+  }
 }