Set up support for Multi-Release jars in Error Prone

bnd.bnd

@@ -0,0 +1 @@
+-fixupmessages: "Classes found in the wrong directory"; restrict:=error; is:=warning

check_api/pom.xml

@@ -163,6 +163,30 @@
             </path>
           </annotationProcessorPaths>
         </configuration>
+        <executions>
+          <execution>
+            <id>default-compile</id>
+            <configuration>
+              <jdkToolchain>
+                <version>11</version>
+              </jdkToolchain>
+            </configuration>
+          </execution>
+          <execution>
+            <id>java24</id>
+            <configuration>
+              <jdkToolchain>
+                <version>24</version>
+              </jdkToolchain>
+              <compileSourceRoots>
+                <compileSourceRoot>${basedir}/src/main/java24</compileSourceRoot>
+              </compileSourceRoots>
+              <!-- multiReleaseOutput requires setting release -->
+              <outputDirectory>${project.build.outputDirectory}/META-INF/versions/24</outputDirectory>
+            </configuration>
+          </execution>
+        </executions>
+
       </plugin>
     </plugins>
   </build>

check_api/src/main/java/com/google/errorprone/util/ErrorProneSignatureGenerator.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2024 The Error Prone Authors.
+ *
+ * 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.errorprone.util;
+
+import com.sun.tools.javac.code.Types;
+import com.sun.tools.javac.util.Name;
+import com.sun.tools.javac.util.Names;
+
+class ErrorProneSignatureGenerator extends Types.SignatureGenerator {
+
+  private final com.sun.tools.javac.util.ByteBuffer buffer =
+      new com.sun.tools.javac.util.ByteBuffer();
+
+  private final Names names;
+
+  protected ErrorProneSignatureGenerator(Types types, Names names) {
+    super(types);
+    this.names = names;
+  }
+
+  @Override
+  protected void append(char ch) {
+    buffer.appendByte(ch);
+  }
+
+  @Override
+  protected void append(byte[] ba) {
+    buffer.appendBytes(ba);
+  }
+
+  @Override
+  protected void append(Name name) {
+    buffer.appendName(name);
+  }
+
+  @SuppressWarnings("CatchingUnchecked") // handles InvalidUtfException on JDK 21+
+  @Override
+  public String toString() {
+    try {
+      return buffer.toName(names).toString();
+    } catch (Exception e) {
+      throw new AssertionError(e);
+    }
+  }
+}

check_api/src/main/java/com/google/errorprone/util/Signatures.java

@@ -26,76 +26,26 @@
 import com.sun.tools.javac.code.Types;
 import com.sun.tools.javac.code.Types.DefaultTypeVisitor;
 import com.sun.tools.javac.util.Name;
-import com.sun.tools.javac.util.Names;
 
 /** Signature generation. */
 public final class Signatures {
 
   /** Returns the binary names of the class. */
   public static String classDescriptor(Type type, VisitorState state) {
-    return new Signatures(state).classDescriptor(type);
-  }
-
-  private String classDescriptor(Type type) {
-    SigGen sig = new SigGen();
+    Types types = state.getTypes();
+    ErrorProneSignatureGenerator sig = new ErrorProneSignatureGenerator(types, state.getNames());
     sig.assembleClassSig(types.erasure(type));
     return sig.toString();
   }
 
   /** Returns a JVMS 4.3.3 method descriptor. */
   public static String descriptor(Type type, VisitorState state) {
-    return new Signatures(state).descriptor(type);
-  }
-
-  private String descriptor(Type type) {
-    SigGen sig = new SigGen();
+    Types types = state.getTypes();
+    ErrorProneSignatureGenerator sig = new ErrorProneSignatureGenerator(types, state.getNames());
     sig.assembleSig(types.erasure(type));
     return sig.toString();
   }
 
-  final Types types;
-  final Names names;
-
-  private Signatures(VisitorState state) {
-    this.types = state.getTypes();
-    this.names = state.getNames();
-  }
-
-  private class SigGen extends Types.SignatureGenerator {
-
-    private final com.sun.tools.javac.util.ByteBuffer buffer =
-        new com.sun.tools.javac.util.ByteBuffer();
-
-    protected SigGen() {
-      super(types);
-    }
-
-    @Override
-    protected void append(char ch) {
-      buffer.appendByte(ch);
-    }
-
-    @Override
-    protected void append(byte[] ba) {
-      buffer.appendBytes(ba);
-    }
-
-    @Override
-    protected void append(Name name) {
-      buffer.appendName(name);
-    }
-
-    @SuppressWarnings("CatchingUnchecked") // handles InvalidUtfException on JDK 21+
-    @Override
-    public String toString() {
-      try {
-        return buffer.toName(names).toString();
-      } catch (Exception e) {
-        throw new AssertionError(e);
-      }
-    }
-  }
-
   /**
    * Pretty-prints a method signature for use in diagnostics.
    *
@@ -171,4 +121,6 @@ public String visitType(Type t, Void s) {
           return t.toString();
         }
       };
+
+  private Signatures() {}
 }

check_api/src/main/java24/com/google/errorprone/util/ErrorProneSignatureGenerator.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2024 The Error Prone Authors.
+ *
+ * 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.errorprone.util;
+
+import com.sun.tools.javac.code.Types;
+import com.sun.tools.javac.util.Name;
+import com.sun.tools.javac.util.Names;
+
+class ErrorProneSignatureGenerator extends Types.SignatureGenerator {
+
+  private final com.sun.tools.javac.util.ByteBuffer buffer =
+      new com.sun.tools.javac.util.ByteBuffer();
+
+  private final Names names;
+
+  protected ErrorProneSignatureGenerator(Types types, Names names) {
+    types.super();
+    this.names = names;
+  }
+
+  @Override
+  protected void append(char ch) {
+    buffer.appendByte(ch);
+  }
+
+  @Override
+  protected void append(byte[] ba) {
+    buffer.appendBytes(ba);
+  }
+
+  @Override
+  protected void append(Name name) {
+    buffer.appendName(name);
+  }
+
+  @SuppressWarnings("CatchingUnchecked") // handles InvalidUtfException on JDK 21+
+  @Override
+  public String toString() {
+    try {
+      return buffer.toName(names).toString();
+    } catch (Exception e) {
+      throw new AssertionError(e);
+    }
+  }
+}

pom.xml

@@ -180,7 +180,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.10.1</version>
+        <version>3.13.0</version>
         <configuration>
           <source>11</source>
           <target>11</target>
@@ -264,6 +264,26 @@
           <trimStackTrace>false</trimStackTrace>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-toolchains-plugin</artifactId>
+        <version>3.2.0</version>
+        <configuration>
+          <toolchains>
+            <jdk>
+              <version>11</version>
+              <version>24</version>
+            </jdk>
+          </toolchains>
+        </configuration>
+        <executions>
+          <execution>
+            <goals>
+              <goal>toolchain</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>