clues: Fix three step cryptic clue getLocations NPE

Prior to this commit, ThreeStepCrypticClue simply returned a
concatenation of the active step locations without filtering the mapped
locations in any way. This could lead to NPEs in the plugin as some
cryptic clues have null locations for steps which have no specific
location or have a variable location. This commit addresses this by
making CrypticClue's location field `@Nullable`, filtering null
locations from ThreeStepCrypticClue's getLocations stream, and by adding
a test to ensure ThreeStepCrypticClue's getLocations method cannot yield
any null entries in its return value.

runelite-client/src/main/java/net/runelite/client/plugins/cluescrolls/clues/CrypticClue.java

@@ -330,6 +330,7 @@ public class CrypticClue extends ClueScroll implements TextClueScroll, NpcClueSc
 	private final String text;
 	private final String npc;
 	private final int objectId;
+	@Nullable
 	private final WorldPoint location;
 	private final String solution;
 	@Nullable
@@ -371,7 +372,7 @@ public class CrypticClue extends ClueScroll implements TextClueScroll, NpcClueSc
 		this(text, npc, objectId, location, solution, null);
 	}
 
-	private CrypticClue(String text, String npc, int objectId, WorldPoint location, String solution, @Nullable String questionText)
+	private CrypticClue(String text, String npc, int objectId, @Nullable WorldPoint location, String solution, @Nullable String questionText)
 	{
 		this.text = text;
 		this.npc = npc;

runelite-client/src/main/java/net/runelite/client/plugins/cluescrolls/clues/ThreeStepCrypticClue.java

@@ -30,6 +30,7 @@ import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import net.runelite.api.InventoryID;
@@ -167,6 +168,7 @@ public class ThreeStepCrypticClue extends ClueScroll implements TextClueScroll,
 		return clueSteps.stream()
 			.filter(s -> !s.getValue())
 			.map(s -> s.getKey().getLocation())
+			.filter(Objects::nonNull)
 			.toArray(WorldPoint[]::new);
 	}
 

runelite-client/src/test/java/net/runelite/client/plugins/cluescrolls/clues/ThreeStepCrypticClueTest.java

@@ -24,6 +24,10 @@
  */
 package net.runelite.client.plugins.cluescrolls.clues;
 
+import com.google.common.base.Joiner;
+import net.runelite.api.coords.WorldPoint;
+import net.runelite.client.util.Text;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import org.junit.Test;
 
@@ -34,4 +38,17 @@ public class ThreeStepCrypticClueTest
 	{
 		assertNull(ThreeStepCrypticClue.forText("", ""));
 	}
+
+	@Test
+	public void nonNullLocations()
+	{
+		final String clueText = Joiner.on("<br><br>").join(CrypticClue.CLUES.stream().map(CrypticClue::getText).toArray());
+		final ThreeStepCrypticClue clue = ThreeStepCrypticClue.forText(Text.sanitizeMultilineText(clueText).toLowerCase(), clueText);
+
+		assertNotNull(clue);
+		for (final WorldPoint location : clue.getLocations())
+		{
+			assertNotNull(location);
+		}
+	}
 }