Use relocated protobuf runtime

Generated protobuf code must be run with the protobuf runtime using the exact same version as the generator used. This is currently a soft constraint, but it is likely that protobuf will enforce that in future protobuf versions. Using a different version of the protobuf runtime can (and does) lead to issues at runtime, see [this issue for an example](protocolbuffers/protobuf#11986).

This change adds a new Nessie artifact `nessie-protobuf-relocated` which contains a relocated protobuf runtime that is used by all other Nessie artifacts.

Also:
* Move `*.proto` files into the directories corresponding to the Java package names.
* Remove the `ProtobufHelperPlugin`, as the underlying issue (not exposing the generated java source folders in IDEs) has been fixed.
* Do not apply checkstyle to Gradle projects that just generate protobuf code (the `ProtobufHelperPlugin` did that before).

Side note: CEL-Java heavily depends on protobuf itself via its API and not just as a runtime/compile-only dependency. As long as no generated protobuf code is being used, it _should_ be okay to use a different protobuf version at runtime, but there is and will be no guarantee.

buildSrc/build.gradle.kts

@@ -30,7 +30,6 @@ dependencies {
   implementation(baselibs.jandex)
   implementation(baselibs.idea.ext)
   implementation(baselibs.shadow)
-  implementation(baselibs.protobuf)
   implementation(baselibs.errorprone)
   implementation(baselibs.nessie.buildsupport.reflectionconfig)
 

buildSrc/src/main/kotlin/Checkstyle.kt

@@ -29,6 +29,10 @@ import org.gradle.kotlin.dsl.withType
 class NessieCheckstylePlugin : Plugin<Project> {
   override fun apply(project: Project): Unit =
     project.run {
+      if (project.name.endsWith("-proto")) {
+        return
+      }
+
       apply<CheckstylePlugin>()
       configure<CheckstyleExtension> {
         toolVersion = libsRequiredVersion("checkstyle")

gradle/baselibs.versions.toml

@@ -5,7 +5,6 @@ errorpronePlugin = "3.0.1"
 jandexPlugin = "1.87"
 junit = "5.9.2"
 nessieBuildPlugins = "0.2.21"
-protobufPlugin = "0.9.2"
 shadowPlugin = "8.1.1"
 spotlessPlugin = "6.17.0"
 
@@ -21,4 +20,3 @@ junit-jupiter-params = { module = "org.junit.jupiter:junit-jupiter-params" }
 nessie-buildsupport-reflectionconfig = { module = "org.projectnessie.buildsupport:reflection-config", version.ref = "nessieBuildPlugins" }
 shadow = { module = "com.github.johnrengelman:shadow", version.ref = "shadowPlugin" }
 spotless = { module = "com.diffplug.spotless:spotless-plugin-gradle", version.ref = "spotlessPlugin" }
-protobuf = { module = "com.google.protobuf:protobuf-gradle-plugin", version.ref = "protobufPlugin" }

gradle/libs.versions.toml

@@ -226,4 +226,5 @@ jmh = { id = "me.champeau.jmh", version = "0.7.0" }
 nessie-run = { id = "org.projectnessie", version = "0.29.0" }
 nexus-publish-plugin = { id = "io.github.gradle-nexus.publish-plugin", version = "1.3.0" }
 node-gradle = { id = "com.github.node-gradle.node", version = "3.5.1" }
+protobuf = { id = "com.google.protobuf", version = "0.9.2" }
 quarkus = { id = "io.quarkus", version.ref = "quarkus" }

gradle/projects.main.properties

@@ -26,6 +26,7 @@ nessie-services=servers/services
 nessie-server-store=servers/store
 nessie-server-store-proto=servers/store-proto
 nessie-content-generator=tools/content-generator
+nessie-protobuf-relocated=tools/protobuf-relocated
 nessie-ui=ui
 nessie-versioned-persist-adapter=versioned/persist/adapter
 nessie-versioned-persist-bench=versioned/persist/bench

tools/protobuf-relocated/build.gradle.kts

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2023 Dremio
+ *
+ * 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 com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+plugins {
+  `java-library`
+  `maven-publish`
+  signing
+  id("org.projectnessie.buildsupport.reflectionconfig")
+  `nessie-conventions`
+}
+
+apply<NessieShadowJarPlugin>()
+
+extra["maven.name"] = "Nessie - Relocated Protobuf ${libs.protobuf.java.get().version}"
+
+dependencies { implementation(libs.protobuf.java) }
+
+reflectionConfig {
+  // Consider classes that extend one of these classes...
+  classExtendsPatterns.set(
+    listOf(
+      "com.google.protobuf.GeneratedMessageV3",
+      "com.google.protobuf.GeneratedMessageV3.Builder"
+    )
+  )
+  // ... and classes the implement this interface.
+  classImplementsPatterns.set(listOf("com.google.protobuf.ProtocolMessageEnum"))
+  // Also include generated classes (e.g. google.protobuf.Empty) via the "runtimeClasspath",
+  // which contains the the "com.google.protobuf:protobuf-java" dependency.
+  includeConfigurations.set(listOf("runtimeClasspath"))
+  relocations.put("com[.]google[.]protobuf[.]", "org.projectnessie.nessie.relocated.protobuf.$1")
+}
+
+tasks.named<ShadowJar>("shadowJar") {
+  dependsOn("generateReflectionConfig")
+  relocate("com.google.protobuf", "org.projectnessie.nessie.relocated.protobuf")
+  manifest { attributes["Google-Protobuf-Version"] = libs.protobuf.java.get().version }
+}