From a417884173df32d27e489b418d26101085de81bd Mon Sep 17 00:00:00 2001
From: Max Schaefer <max@semmle.com>
Date: Thu, 20 Jun 2019 17:01:43 +0100
Subject: [PATCH] JavaScript: Fix potential null-pointer exception in YAML
 extractor.

`ScalarEvent.getStyle()` is documented as returning `null` for plain
scalars, so we need to handle that specially (cf
https://github.com/Semmle/ql/blob/master/javascript/ql/src/semmle/javascript/YAML.qll#L100
for the corresponding code in the library, which expects plain style to
be encoded as zero).
---
 .../extractor/src/com/semmle/js/extractor/YAMLExtractor.java  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/javascript/extractor/src/com/semmle/js/extractor/YAMLExtractor.java b/javascript/extractor/src/com/semmle/js/extractor/YAMLExtractor.java
index 0fa9f2a371b..c1917492fb2 100644
--- a/javascript/extractor/src/com/semmle/js/extractor/YAMLExtractor.java
+++ b/javascript/extractor/src/com/semmle/js/extractor/YAMLExtractor.java
@@ -166,8 +166,10 @@ public class YAMLExtractor implements IExtractor {
                 NodeId.scalar,
                 scalar.getValue(),
                 scalar.getImplicit().canOmitTagInPlainScalar());
+        Character style = scalar.getStyle();
+        int styleCode = style == null ? 0 : (int) style;
         trapWriter.addTuple(
-            YAMLTables.YAML_SCALARS, label, (int) scalar.getStyle(), scalar.getValue());
+            YAMLTables.YAML_SCALARS, label, styleCode, scalar.getValue());
       } else if (start.is(Event.ID.SequenceStart)) {
         kind = NodeKind.SEQUENCE;
         SequenceStartEvent sequenceStart = (SequenceStartEvent) start;