GH-299: Add reproduction for GH-299 dependency issue

Adds a dependency on the latest version of ehcache at the time
of writing which references an invalid version of JAXB internally
which is unavailable on most modern JDKs.

protobuf-maven-plugin/src/it/gh-299-ehcache-jaxb-resolution-failure/invoker.properties

@@ -0,0 +1,17 @@
+#
+# Copyright (C) 2023 - 2024, Ashley Scopes.
+#
+# 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.
+#
+
+invoker.goals = clean package

protobuf-maven-plugin/src/it/gh-299-ehcache-jaxb-resolution-failure/pom.xml

@@ -0,0 +1,95 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    Copyright (C) 2023 - 2024, Ashley Scopes.
+
+    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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>@project.groupId@</groupId>
+    <artifactId>protobuf-maven-plugin-parent</artifactId>
+    <version>@project.version@</version>
+    <relativePath>../../../../pom.xml</relativePath>
+  </parent>
+
+  <groupId>gh-299-ehcache-jaxb-resolution-failure</groupId>
+  <artifactId>gh-299-ehcache-jaxb-resolution-failure</artifactId>
+
+  <properties>
+    <protobuf.version>4.27.2</protobuf.version>
+    <ehcache.version>3.10.8</ehcache.version>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.protobuf</groupId>
+      <artifactId>protobuf-java</artifactId>
+      <version>${protobuf.version}</version>
+    </dependency>
+
+    <dependency>
+      <!-- This version of ehcache pulls in an invalid system-path JAXB dependency that does not
+           exist on newer JDKs. In GH-299, we were erroneously trying to resolve that dependency,
+           despite it only being marked with the `runtime' scope, which we should have been
+           ignoring.
+
+           If this build succeeds, it means we no longer have an issue with this specific dependency
+           and that GH-299 has been fixed. -->
+      <groupId>org.ehcache</groupId>
+      <artifactId>ehcache</artifactId>
+      <version>${ehcache.version}</version>
+      <classifier>jakarta</classifier>
+
+      <exclusions>
+        <exclusion>
+          <!-- This points to blocked repositories. -->
+          <groupId>org.glassfish.jaxb</groupId>
+          <artifactId>jaxb-runtime</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+      </plugin>
+
+      <plugin>
+        <groupId>@project.groupId@</groupId>
+        <artifactId>@project.artifactId@</artifactId>
+        <version>@project.version@</version>
+
+        <configuration>
+          <protocVersion>${protobuf.version}</protocVersion>
+        </configuration>
+
+        <executions>
+          <execution>
+            <goals>
+              <goal>generate</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

protobuf-maven-plugin/src/it/gh-299-ehcache-jaxb-resolution-failure/selector.groovy

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2023 - 2024, Ashley Scopes.
+ *
+ * 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.
+ */
+if ("uname -o".execute().text =~ /Android.*/) {
+  println("Skipping test as it uses incompatible binaries for Android")
+  return false
+} else {
+  return true
+}

protobuf-maven-plugin/src/it/gh-299-ehcache-jaxb-resolution-failure/src/main/protobuf/org/example/helloworld.proto

@@ -0,0 +1,27 @@
+//
+// Copyright (C) 2023 - 2024, Ashley Scopes.
+//
+// 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.
+//
+
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.example.helloworld";
+
+package org.example.helloworld;
+
+message GreetingRequest {
+  string name = 1;
+}
+

protobuf-maven-plugin/src/it/gh-299-ehcache-jaxb-resolution-failure/test.groovy

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2023 - 2024, Ashley Scopes.
+ *
+ * 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.
+ */
+
+import java.nio.file.Path
+
+import static org.assertj.core.api.Assertions.assertThat
+
+Path expectedClass = basedir.toPath().toAbsolutePath().resolve("target")
+    .resolve("classes")
+    .resolve("org")
+    .resolve("example")
+    .resolve("helloworld")
+    .resolve("GreetingRequest.class")
+
+// Verify compilation succeeded.
+assertThat(expectedClass)
+    .isRegularFile()
+
+return true