Force java_generic_services to false for protos gathered from depende…

…ncies

docs/src/main/asciidoc/grpc-getting-started.adoc

@@ -118,6 +118,8 @@ message HelloReply {
 
 This `proto` file defines a simple service interface with a single method (`SayHello`), and the exchanged messages (`HelloRequest` containing the name and `HelloReply` containing the greeting message).
 
+NOTE: Your `proto` file must not contain `option java_generic_services = true;`. https://developers.google.com/protocol-buffers/docs/reference/java-generated?hl=en#service[Generic services are deprecated] and are not compatible with Quarkus code generation plugins.
+
 Before coding, we need to generate the classes used to implement and consume gRPC services.
 In a terminal, run:
 
@@ -178,6 +180,8 @@ quarkus.generate-code.grpc.scan-for-proto=<groupId>:<artifactId>
 ----
 The value of the property may be `none`, which is the default value, or a comma separated list of `groupId:artifactId` coordinates.
 
+NOTE: `option java_generic_services = true;` will automatically be removed from proto file containing it.
+
 == Different gRPC implementations / types
 
 Another thing to take note as well is that Quarkus' gRPC support currently includes 3 different types of gRPC usage:

extensions/grpc/codegen/src/main/java/io/quarkus/grpc/deployment/GrpcCodeGen.java

@@ -146,6 +146,35 @@ public boolean trigger(CodeGenContext context) throws CodeGenException {
         return false;
     }
 
+    private static void copySanitizedProtoFile(ResolvedDependency artifact, Path protoPath, Path outProtoPath)
+            throws IOException {
+        boolean genericServicesFound = false;
+
+        try (var reader = Files.newBufferedReader(protoPath);
+                var writer = Files.newBufferedWriter(outProtoPath)) {
+
+            String line = reader.readLine();
+            while (line != null) {
+                // filter java_generic_services to avoid "Tried to write the same file twice"
+                // when set to true. Generic services are deprecated and replaced by classes generated by
+                // this plugin
+                if (!line.contains("java_generic_services")) {
+                    writer.write(line);
+                    writer.newLine();
+                } else {
+                    genericServicesFound = true;
+                }
+
+                line = reader.readLine();
+            }
+        }
+
+        if (genericServicesFound) {
+            log.infof("Ignoring option java_generic_services in %s:%s%s.", artifact.getGroupId(), artifact.getArtifactId(),
+                    protoPath);
+        }
+    }
+
     private void postprocessing(CodeGenContext context, Path outDir) {
         if (TRUE.toString().equalsIgnoreCase(System.getProperties().getProperty(POST_PROCESS_SKIP, "false"))
                 || context.config().getOptionalValue(POST_PROCESS_SKIP, Boolean.class).orElse(false)) {
@@ -179,7 +208,7 @@ private Collection<Path> gatherProtosFromDependencies(Path workDir, Set<String>
             if (scanAll
                     || dependenciesToScan.contains(
                             String.format("%s:%s", artifact.getGroupId(), artifact.getArtifactId()))) {
-                extractProtosFromArtifact(workDir, protoFilesFromDependencies, protoDirectories, artifact);
+                extractProtosFromArtifact(workDir, protoFilesFromDependencies, protoDirectories, artifact, true);
             }
         }
         return protoFilesFromDependencies;
@@ -215,14 +244,14 @@ private Collection<String> gatherDirectoriesWithImports(Path workDir, CodeGenCon
             if (scanAll
                     || dependenciesToScan.contains(
                             String.format("%s:%s", artifact.getGroupId(), artifact.getArtifactId()))) {
-                extractProtosFromArtifact(workDir, new ArrayList<>(), importDirectories, artifact);
+                extractProtosFromArtifact(workDir, new ArrayList<>(), importDirectories, artifact, false);
             }
         }
         return importDirectories;
     }
 
     private void extractProtosFromArtifact(Path workDir, Collection<Path> protoFiles,
-            Set<String> protoDirectories, ResolvedDependency artifact) throws CodeGenException {
+            Set<String> protoDirectories, ResolvedDependency artifact, boolean isDependency) throws CodeGenException {
 
         try {
             artifact.getContentTree().walk(
@@ -250,7 +279,11 @@ private void extractProtosFromArtifact(Path workDir, Collection<Path> protoFiles
                                 }
                                 try {
                                     Files.createDirectories(outPath.getParent());
-                                    Files.copy(path, outPath, StandardCopyOption.REPLACE_EXISTING);
+                                    if (isDependency) {
+                                        copySanitizedProtoFile(artifact, path, outPath);
+                                    } else {
+                                        Files.copy(path, outPath, StandardCopyOption.REPLACE_EXISTING);
+                                    }
                                     protoFiles.add(outPath);
                                 } catch (IOException e) {
                                     throw new GrpcCodeGenException("Failed to extract proto file" + path + " to target: "

integration-tests/grpc-external-proto/src/main/resources/dir/proto-with-java_generic_services.proto

@@ -0,0 +1,14 @@
+syntax = "proto3";
+
+option java_package = "com.test";
+
+// codegen will ignore the line below
+option java_generic_services = true;
+
+package com.test;
+
+service MyJavaGenericServicesTest {
+  rpc DoTest(JavaGenericServices) returns (JavaGenericServices);
+}
+
+message JavaGenericServices {}