Fix JPMS split package violations and enable documentation generation

Resolves module system conflicts by moving liteproto extension from shared
com.google.common.truth.extensions.proto package to unique
com.google.common.truth.extensions.liteproto namespace. This eliminates
split package violations that prevented proper module boundaries.

Enables aggregated Javadoc generation using legacyMode=true to work around
protobuf dependency conflicts between liteproto (protobuf-lite:3.0.1) and
proto (protobuf-java:4.32.1) extensions that caused module-path failures.

Author: cowwoc

core/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>com.google.truth</groupId>
     <artifactId>truth-parent</artifactId>
-    <version>HEAD-SNAPSHOT</version>
+    <version>999.0.0-SNAPSHOT</version>
   </parent>
   <artifactId>truth</artifactId>
   <name>Truth Core</name>
@@ -98,23 +98,6 @@
             </path>
           </annotationProcessorPaths>
         </configuration>
-        <executions>
-          <execution>
-            <id>compile-java9</id>
-            <goals>
-              <goal>compile</goal>
-            </goals>
-            <configuration>
-              <release>9</release>
-              <compileSourceRoots>
-                <compileSourceRoot>${project.basedir}/src/main/java9</compileSourceRoot>
-              </compileSourceRoots>
-              <multiReleaseOutput>true</multiReleaseOutput>
-              <useIncrementalCompilation>false</useIncrementalCompilation>
-              <moduleVersion>1.0</moduleVersion>
-            </configuration>
-          </execution>
-        </executions>
       </plugin>
       <plugin>
         <artifactId>maven-source-plugin</artifactId>

core/src/main/java9/module-info.java renamed to core/src/main/java/module-info.java

@@ -17,11 +17,13 @@
 module com.google.truth {
     requires com.google.common;
     requires junit;
+    requires java.compiler;
 
     requires static org.jspecify;
     requires static com.google.errorprone.annotations;
     requires static org.objectweb.asm;
     requires static auto.value.annotations;
+    requires static com.google.j2objc.annotations;
 
     exports com.google.common.truth;
 }

extensions/java8/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>com.google.truth.extensions</groupId>
     <artifactId>truth-extensions-parent</artifactId>
-    <version>HEAD-SNAPSHOT</version>
+    <version>999.0.0-SNAPSHOT</version>
   </parent>
   <artifactId>truth-java8-extension</artifactId>
   <name>Obsolete Truth Extension for Java8</name>

extensions/liteproto/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>com.google.truth.extensions</groupId>
     <artifactId>truth-extensions-parent</artifactId>
-    <version>HEAD-SNAPSHOT</version>
+    <version>999.0.0-SNAPSHOT</version>
   </parent>
   <artifactId>truth-liteproto-extension</artifactId>
   <name>Truth Extension for Lite Protocol Buffers</name>
@@ -96,21 +96,6 @@
             </path>
           </annotationProcessorPaths>
         </configuration>
-        <executions>
-          <execution>
-            <id>compile-java9</id>
-            <goals>
-              <goal>compile</goal>
-            </goals>
-            <configuration>
-              <release>9</release>
-              <compileSourceRoots>
-                <compileSourceRoot>${project.basedir}/src/main/java9</compileSourceRoot>
-              </compileSourceRoots>
-              <multiReleaseOutput>true</multiReleaseOutput>
-            </configuration>
-          </execution>
-        </executions>
       </plugin>
       <plugin>
         <artifactId>maven-jar-plugin</artifactId>

extensions/liteproto/src/main/java/com/google/common/truth/extensions/proto/LiteProtoSubject.java renamed to extensions/liteproto/src/main/java/com/google/common/truth/extensions/liteproto/LiteProtoSubject.java

@@ -14,18 +14,19 @@
  * limitations under the License.
  */
 
-package com.google.common.truth.extensions.proto;
+package com.google.common.truth.extensions.liteproto;
 
 import static com.google.common.base.Strings.lenientFormat;
 import static com.google.common.truth.Fact.fact;
 import static com.google.common.truth.Fact.simpleFact;
-import static com.google.common.truth.extensions.proto.Platform.getTrimmedToString;
+import static com.google.common.truth.extensions.liteproto.Platform.getTrimmedToString;
 
 import com.google.common.annotations.GwtIncompatible;
 import com.google.common.annotations.J2ktIncompatible;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.Subject;
+import com.google.common.truth.extensions.liteproto.internal.LiteProtoSubjectAccess;
 import com.google.errorprone.annotations.CheckReturnValue;
 import com.google.j2objc.annotations.J2ObjCIncompatible;
 import com.google.protobuf.MessageLite;
@@ -44,6 +45,16 @@
 @NullMarked
 public class LiteProtoSubject extends Subject {
 
+  // Static initializer to register SharedSecrets accessor
+  static {
+    LiteProtoSubjectAccess.setAccessor(new LiteProtoSubjectAccess.Accessor() {
+      @Override
+      public String getCustomStringRepresentation(LiteProtoSubject subject) {
+        return subject.actualCustomStringRepresentationForProtoPackageMembersToCall();
+      }
+    });
+  }
+
   /**
    * Returns a {@code Subject.Factory} for {@link MessageLite} subjects which you can use to assert
    * things about Lite Protobuf properties.

extensions/liteproto/src/main/java/com/google/common/truth/extensions/proto/LiteProtoTruth.java renamed to extensions/liteproto/src/main/java/com/google/common/truth/extensions/liteproto/LiteProtoTruth.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.google.common.truth.extensions.proto;
+package com.google.common.truth.extensions.liteproto;
 
 import static com.google.common.truth.Truth.assertAbout;
 

extensions/liteproto/src/main/java/com/google/common/truth/extensions/proto/Platform.java renamed to extensions/liteproto/src/main/java/com/google/common/truth/extensions/liteproto/Platform.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.google.common.truth.extensions.proto;
+package com.google.common.truth.extensions.liteproto;
 
 import static com.google.common.base.Strings.lenientFormat;
 

extensions/liteproto/src/main/java/com/google/common/truth/extensions/liteproto/internal/LiteProtoSubjectAccess.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2024 Google, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.common.truth.extensions.liteproto.internal;
+
+import com.google.common.truth.extensions.liteproto.LiteProtoSubject;
+
+/**
+ * Provides access to package-private methods in LiteProtoSubject for use by
+ * other Truth extensions.
+ *
+ * <p><b>This is an internal API and should not be used by client code.</b>
+ * This class may be removed or changed at any time without notice.
+ */
+public final class LiteProtoSubjectAccess {
+
+  /**
+   * Accessor interface for LiteProtoSubject internal methods.
+   * Set by LiteProtoSubject during class initialization.
+   */
+  public interface Accessor {
+    String getCustomStringRepresentation(LiteProtoSubject subject);
+  }
+
+  private static Accessor accessor;
+
+  /**
+   * Sets the accessor. This is called by LiteProtoSubject during class initialization.
+   *
+   * @param accessor the accessor implementation
+   * @throws IllegalStateException if the accessor is already set
+   */
+  public static void setAccessor(Accessor accessor) {
+    if (LiteProtoSubjectAccess.accessor != null) {
+      throw new IllegalStateException("Accessor already set");
+    }
+    LiteProtoSubjectAccess.accessor = accessor;
+  }
+
+  /**
+   * Gets the custom string representation for the given LiteProtoSubject.
+   *
+   * @param subject the LiteProtoSubject instance
+   * @return the custom string representation
+   * @throws IllegalStateException if no accessor has been set
+   */
+  public static String getCustomStringRepresentation(LiteProtoSubject subject) {
+    if (accessor == null) {
+      throw new IllegalStateException("No accessor set");
+    }
+    return accessor.getCustomStringRepresentation(subject);
+  }
+
+  private LiteProtoSubjectAccess() {}
+}

extensions/liteproto/src/main/java/com/google/common/truth/extensions/proto/package-info.java

@@ -17,10 +17,14 @@
 module com.google.truth.extensions.liteproto {
     requires com.google.truth;
     requires com.google.common;
+    requires java.compiler;
 
     requires static org.jspecify;
     requires static com.google.errorprone.annotations;
-    requires static com.google.protobuf.lite;
+    requires static protobuf.lite;
+    requires static auto.value.annotations;
+    requires static com.google.j2objc.annotations;
 
-    exports com.google.common.truth.extensions.proto;
+    exports com.google.common.truth.extensions.liteproto;
+    exports com.google.common.truth.extensions.liteproto.internal to com.google.truth.extensions.proto;
 }