Fix schema evolution involving maps of non-scalar

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/deser/AvroReaderFactory.java

@@ -289,7 +289,7 @@ protected AvroStructureReader createMapReader(Schema writerSchema, Schema reader
                 String valueTypeId = readerSchema.getValueType().getProp(AvroSchemaHelper.AVRO_SCHEMA_PROP_CLASS);
                 return MapReader.construct(dec, typeId, keyTypeId, valueTypeId);
             }
-            return MapReader.construct(createReader(writerElementType, readerSchema.getElementType()), typeId, keyTypeId);
+            return MapReader.construct(createReader(writerElementType, readerSchema.getValueType()), typeId, keyTypeId);
         }
 
         protected AvroStructureReader createRecordReader(Schema writerSchema, Schema readerSchema)

avro/src/test/java/com/fasterxml/jackson/dataformat/avro/schemaev/RecordEvolutionTest.java

@@ -0,0 +1,161 @@
+package com.fasterxml.jackson.dataformat.avro.schemaev;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.dataformat.avro.*;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+public class RecordEvolutionTest extends AvroTestBase
+{
+	static String SCHEMA_V1 = "{\n"
+        + " \"type\": \"record\",\n"
+        + " \"name\": \"User\",\n"
+        + " \"fields\": [\n"
+        + "     {\n"
+        + "        \"name\": \"name\",\n"
+        + "        \"type\": [\"string\", \"null\"],\n"
+        + "        \"default\": null\n"
+        + "    },\n"
+        + "     {\n"
+        + "        \"name\": \"preferences\", \n"
+        + "        \"type\": {\n"
+        + "            \"type\": \"map\",\n"
+        + "            \"values\": {\n"
+        + "                \"type\": \"array\",\n"
+        + "                \"items\": \"string\"\n"
+        + "            }\n"
+        + "        }\n"
+        + "    }\n"
+        + " ]\n"
+        + "}";
+
+	static String SCHEMA_V2 = "{\n"
+        + " \"type\": \"record\",\n"
+        + " \"name\": \"User\",\n"
+        + " \"fields\": [\n"
+        + "     {\n"
+        + "        \"name\": \"fullName\",\n"
+        + "        \"type\": [\"string\", \"null\"],\n"
+        + "        \"default\": null,\n"
+        + "        \"aliases\": [\"name\"]\n"
+        + "    },\n"
+        + "     {\n"
+        + "        \"name\": \"preferences\", \n"
+        + "        \"type\": {\n"
+        + "            \"type\": \"map\",\n"
+        + "            \"values\": {\n"
+        + "                \"type\": \"array\",\n"
+        + "                \"items\": \"string\"\n"
+        + "            }\n"
+        + "        }\n"
+        + "    }\n"
+        + " ]\n"
+        + "}";
+
+	static class UserV1 {
+		public String name;
+		public Map<String, List<String>> preferences;
+
+		@JsonCreator
+		public UserV1(final String name, final Map<String, List<String>> preferences) {
+			this.name = name;
+			this.preferences = preferences;
+		}
+
+		public boolean equals(final Object object) {
+			if (this == object) {
+				return true;
+			}
+
+			if (!(object instanceof UserV1)) {
+				return false;
+			}
+
+			final UserV1 user = (UserV1) object;
+
+			return name.equals(user.name) &&
+				preferences.equals(user.preferences);
+		}
+
+		public int hashCode() {
+			return Objects.hash(name, preferences);
+		}
+
+		@Override
+		public String toString() {
+			return "UserV1{" +
+				"name='" + name + '\'' +
+				", preferences=" + preferences +
+				'}';
+		}
+	}
+
+	static class UserV2 {
+		public String fullName;
+		public Map<String, List<String>> preferences;
+
+		public UserV2(
+			@JsonProperty("fullName") final String fullName,
+			@JsonProperty("preferences") final Map<String, List<String>> preferences
+		) {
+			this.fullName = fullName;
+			this.preferences = preferences;
+		}
+
+		public boolean equals(final Object object) {
+			if (this == object) {
+				return true;
+			}
+
+			if (!(object instanceof UserV2)) {
+				return false;
+			}
+
+			final UserV2 user = (UserV2) object;
+
+			return fullName.equals(user.fullName) && preferences.equals(user.preferences);
+		}
+
+		public int hashCode() {
+			return Objects.hash(fullName, preferences);
+		}
+
+		@Override
+		public String toString() {
+			return "UserV2{" +
+				"fullName='" + fullName + '\'' +
+				", preferences=" + preferences +
+				'}';
+		}
+	}
+
+	private final AvroMapper MAPPER = getMapper();
+
+	public void testEvolutionInvolvingComplexRecords() throws Exception
+	{
+		final AvroSchema schemaV1 = MAPPER.schemaFrom(SCHEMA_V1);
+		final AvroSchema schemaV2 = MAPPER.schemaFrom(SCHEMA_V2);
+		final AvroSchema combinedSchema = schemaV1.withReaderSchema(schemaV2);
+
+		final Map<String, List<String>> preferences = new HashMap<>();
+		final List<String> list = new ArrayList<>();
+		list.add("yes");
+
+		preferences.put("jackson", list);
+
+		final UserV1 userV1 = new UserV1("foo", preferences);
+
+		final byte[] avro = MAPPER.writer(schemaV1).writeValueAsBytes(userV1);
+
+		final UserV2 userV2 = MAPPER.readerFor(UserV2.class)
+			.with(combinedSchema)
+			.readValue(avro);
+
+		assertEquals(userV2.fullName, userV1.name);
+		assertEquals(userV2.preferences, userV1.preferences);
+	}
+}