Fix #4994 CoercionConfig for CoercionAction.AsNull not working on empty array deserialization

src/main/java/com/fasterxml/jackson/databind/deser/std/StringArrayDeserializer.java

@@ -179,6 +179,22 @@ public String[] deserialize(JsonParser p, DeserializationContext ctxt) throws IO
         }
         String[] result = buffer.completeAndClearBuffer(chunk, ix, String.class);
         ctxt.returnObjectBuffer(buffer);
+        if (result != null) {
+            if (result.length == 0) {
+                // [databind#4949]: Coercion from empty array not applied
+                result = coerceEmptyArray(result, ctxt);
+            }
+        }
+        return result;
+    }
+
+    private String[] coerceEmptyArray(String[] result, DeserializationContext ctxt)
+            throws JsonMappingException
+    {
+        final CoercionAction act = ctxt.findCoercionAction(logicalType(), handledType(), CoercionInputShape.EmptyArray);
+        if (act == CoercionAction.AsNull) {
+            return null;
+        }
         return result;
     }
 

src/test/java/com/fasterxml/jackson/databind/convert/CoerceEmptyArrayAsNull4994Test.java

@@ -0,0 +1,37 @@
+package com.fasterxml.jackson.databind.convert;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.cfg.CoercionAction;
+import com.fasterxml.jackson.databind.cfg.CoercionInputShape;
+import com.fasterxml.jackson.databind.testutil.DatabindTestUtil;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+// [databind#4994] CoercionConfig for empty arrays not working as expected
+public class CoerceEmptyArrayAsNull4994Test
+    extends DatabindTestUtil
+{
+    public static class Pojo4994 {
+        public String[] value;
+    }
+
+    @Test
+    public void testAsNull()
+        throws Exception
+    {
+        final ObjectMapper MAPPER_TO_NULL = jsonMapperBuilder()
+                .withCoercionConfigDefaults(cfg ->
+                        cfg.setCoercion(CoercionInputShape.EmptyArray, CoercionAction.AsNull))
+                .build();
+
+        String json = "{\"value\": []}";
+
+        Pojo4994 pojo = MAPPER_TO_NULL.readValue(json, Pojo4994.class);
+
+        assertNull(pojo.value); // expected: <null> but was: <[]>
+    }
+
+}