From c6d33effa03f7d726ffb663d3440b4a713e0f286 Mon Sep 17 00:00:00 2001
From: David Roberts <dave.roberts@elastic.co>
Date: Mon, 12 Nov 2018 16:50:15 +0000
Subject: [PATCH] [ML] Fix find_file_structure NPE with should_trim_fields

The NPE would occur if should_trim_field was overridden to
true and any field value was completely blank.  This change
defends against this situation.

Fixes #35462
---
 .../ml/filestructurefinder/DelimitedFileStructureFinder.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinder.java b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinder.java
index de938d0a9518c..93d440b79d434 100644
--- a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinder.java
+++ b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinder.java
@@ -82,7 +82,7 @@ static DelimitedFileStructureFinder makeDelimitedFileStructureFinder(List<String
             int lineNumber = lineNumbers.get(index);
             Map<String, String> sampleRecord = new LinkedHashMap<>();
             Util.filterListToMap(sampleRecord, columnNames,
-                trimFields ? row.stream().map(String::trim).collect(Collectors.toList()) : row);
+                trimFields ? row.stream().map(field -> (field == null) ? null : field.trim()).collect(Collectors.toList()) : row);
             sampleRecords.add(sampleRecord);
             sampleMessages.add(
                 sampleLines.subList(prevMessageEndLineNumber + 1, lineNumbers.get(index)).stream().collect(Collectors.joining("\n")));