Fix NPE in StringSwitchJavacFilter

org.jacoco.core.test/src/org/jacoco/core/internal/analysis/filter/StringSwitchJavacFilterTest.java

@@ -115,6 +115,57 @@ public void should_filter_when_javac_generates_lookupswitch() {
 		assertIgnored(new Range(expectedFromInclusive, expectedToInclusive));
 	}
 
+	/**
+	 * <code><pre>
+	 * int c = -1;
+	 * switch (s.hashCode()) {
+	 * case 0:
+	 *   if (s.equals(""))
+	 *     c = 0;
+	 *   return;
+	 * default:
+	 * }
+	 * switch (c)
+	 *   // ...
+	 * </pre></code>
+	 */
+	@Test
+	public void should_not_filter_when_no_expected_goto() {
+		m.visitInsn(Opcodes.ICONST_M1);
+		m.visitVarInsn(Opcodes.ISTORE, 2);
+
+		m.visitVarInsn(Opcodes.ALOAD, 1);
+		m.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "hashCode",
+				"()I", false);
+
+		final Label secondSwitch = new Label();
+		final Label h1 = new Label();
+		m.visitTableSwitchInsn(0, 0, secondSwitch, h1);
+
+		m.visitLabel(h1);
+		m.visitVarInsn(Opcodes.ALOAD, 1);
+		m.visitLdcInsn("");
+		m.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "equals",
+				"(Ljava/lang/Object;)Z", false);
+		m.visitJumpInsn(Opcodes.IFEQ, secondSwitch);
+		m.visitInsn(Opcodes.ICONST_0);
+		m.visitVarInsn(Opcodes.ISTORE, 2);
+
+		// Something different from the expected by filter
+		// secondSwitch label or GOTO:
+		m.visitInsn(Opcodes.RETURN);
+
+		m.visitLabel(secondSwitch);
+		m.visitVarInsn(Opcodes.ILOAD, 2);
+		final Label defaultCase = new Label();
+		m.visitLookupSwitchInsn(defaultCase, new int[] {}, new Label[] {});
+		m.visitLabel(defaultCase);
+
+		filter.filter(m, context, output);
+
+		assertIgnored();
+	}
+
 	@Test
 	public void should_not_filter_code_generated_by_ECJ() {
 		final Label h1 = new Label();

org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchJavacFilter.java

@@ -87,6 +87,9 @@ boolean match(final AbstractInsnNode start,
 					break;
 				}
 				nextIs(Opcodes.GOTO);
+				if (cursor == null) {
+					return false;
+				}
 				if (((JumpInsnNode) cursor).label != secondSwitchLabel) {
 					return false;
 				}

org.jacoco.doc/docroot/doc/changes.html

@@ -20,6 +20,12 @@ <h1>Change History</h1>
 
 <h2>Snapshot Build @qualified.bundle.version@ (@build.date@)</h2>
 
+<h3>Fixed bugs</h3>
+<ul>
+  <li>Fixed <code>NullPointerException</code> during filtering
+      (GitHub <a href="https://github.com/jacoco/jacoco/issues/1189">#1189</a>).</li>
+</ul>
+
 <h2>Release 0.8.7 (2021/05/04)</h2>
 
 <h3>New Features</h3>