[GitHub] [incubator-daffodil] mbeckerle commented on a change in pull request #468: Fix abort when viewing prefixed length elements in the debugger

[GitBox <gi...@apache.org>]

mbeckerle commented on a change in pull request #468:
URL: https://github.com/apache/incubator-daffodil/pull/468#discussion_r542602538



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File path: daffodil-runtime1-unparser/src/main/scala/org/apache/daffodil/processors/unparsers/SpecifiedLengthUnparsers.scala
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@@ -385,8 +388,11 @@ class SpecifiedLengthPrefixedUnparser(
   override lazy val childProcessors = Vector(prefixedLengthUnparser, eUnparser)
 
   override def unparse(state: UState): Unit = {
-    // create a "detached" element that the prefix length will be used to unparse
-    val plElem = Infoset.newElement(prefixedLengthERD).asInstanceOf[DISimple]
+    // Create a "detached" DIDocument with a single child element that the
+    // prefix length will be parsed to. This creates a completely new
+    // infoset and parses to that, so care is taken to ensure this infoset
+    // is only used for the prefix length parsing and is removed afterwards
+    val plElem = Infoset.newDetachedElement(state, prefixedLengthERD).asInstanceOf[DISimple]

Review comment:
       I'm a bit concerned about the overhead of this added node, but we should deal with that via profiling. There are many many overheads in Daffodil, no reason to think this one will be the most important. 




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