build: Move shim directories (#318)

common/pom.xml

@@ -167,6 +167,24 @@ under the License.
         <groupId>net.alchim31.maven</groupId>
         <artifactId>scala-maven-plugin</artifactId>
       </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>add-shim-source</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>src/main/${shims.source}</source>
+              </sources>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
     <resources>
       <resource>

pom.xml

@@ -88,6 +88,7 @@ under the License.
     <argLine>-ea -Xmx4g -Xss4m ${extraJavaTestArgs}</argLine>
     <additional.3_3.test.source>spark-3.3-plus</additional.3_3.test.source>
     <additional.3_4.test.source>spark-3.4</additional.3_4.test.source>
+    <shims.source>spark-3.x</shims.source>
   </properties>
 
   <dependencyManagement>

spark/pom.xml

@@ -250,6 +250,18 @@ under the License.
               </sources>
             </configuration>
           </execution>
+          <execution>
+            <id>add-shim-source</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>src/main/${shims.source}</source>
+              </sources>
+            </configuration>
+          </execution>
         </executions>
       </plugin>
     </plugins>