From d1ca5fa6cd03cdf3588e2ced1bf36e835511f3d3 Mon Sep 17 00:00:00 2001
From: Evgeny Mandrikov <mandrikov@gmail.com>
Date: Sun, 22 Sep 2019 01:22:42 +0200
Subject: [PATCH 1/3] (WIP) add test

---
 .../filter/StringSwitchEcjFilterTest.java      | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilterTest.java b/org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilterTest.java
index 3f726185bf..a13ea8f047 100644
--- a/org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilterTest.java
+++ b/org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilterTest.java
@@ -155,4 +155,22 @@ public void should_filter_when_default_is_first() {
 		assertIgnored(new Range(switchNode.getNext(), expectedToInclusive));
 	}
 
+	@Test
+	public void should_not_filter_empty_lookup_switch() {
+		final MethodNode m = new MethodNode(InstrSupport.ASM_API_VERSION, 0,
+				"name", "(Ljava/lang/String;)V", null, null);
+		m.visitVarInsn(Opcodes.ALOAD, 1);
+		m.visitVarInsn(Opcodes.ASTORE, 2);
+		m.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "hashCode",
+				"()I", false);
+		final Label defaultCase = new Label();
+		m.visitLookupSwitchInsn(defaultCase, null, new Label[] {});
+		m.visitLabel(defaultCase);
+		m.visitInsn(Opcodes.RETURN);
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
 }

From 14dead119084e4d273487fa6ce1d3138990d7589 Mon Sep 17 00:00:00 2001
From: Evgeny Mandrikov <mandrikov@gmail.com>
Date: Sun, 22 Sep 2019 01:35:51 +0200
Subject: [PATCH 2/3] (WIP) fix

---
 .../core/internal/analysis/filter/StringSwitchEcjFilter.java  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilter.java
index e0aba35d89..0e2c1e4d72 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilter.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchEcjFilter.java
@@ -70,6 +70,10 @@ public void match(final AbstractInsnNode start,
 			final Set<AbstractInsnNode> replacements = new HashSet<AbstractInsnNode>();
 			replacements.add(skipNonOpcodes(defaultLabel));
 
+			if (hashCodes == 0) {
+				return;
+			}
+
 			for (int i = 0; i < hashCodes; i++) {
 				while (true) {
 					nextIsVar(Opcodes.ALOAD, "s");

From 6f446fd961e01ff1a878682ba4787683977c05d6 Mon Sep 17 00:00:00 2001
From: Evgeny Mandrikov <mandrikov@gmail.com>
Date: Sun, 22 Sep 2019 14:33:59 +0200
Subject: [PATCH 3/3] (WIP) update changelog

---
 org.jacoco.doc/docroot/doc/changes.html | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/org.jacoco.doc/docroot/doc/changes.html b/org.jacoco.doc/docroot/doc/changes.html
index c1f5bf722c..6197c56d99 100644
--- a/org.jacoco.doc/docroot/doc/changes.html
+++ b/org.jacoco.doc/docroot/doc/changes.html
@@ -48,7 +48,8 @@ <h3>Fixed bugs</h3>
       that source references are actually files
       (GitHub <a href="https://github.com/jacoco/jacoco/issues/941">#941</a>).</li>
   <li><code>NullPointerException</code> during filtering
-      (GitHub <a href="https://github.com/jacoco/jacoco/issues/942">#942</a>).</li>
+      (GitHub <a href="https://github.com/jacoco/jacoco/issues/942">#942</a>,
+      <a href="https://github.com/jacoco/jacoco/issues/944">#944</a>).</li>
 </ul>
 
 <h3>Non-functional Changes</h3>