quarkusio/quarkus · error · CodeGenException

Failed to create a wrapper script for quarkus-grpc plugin

Error message

Failed to create a wrapper script for quarkus-grpc plugin

What it means

To run the Quarkus protoc plugin, writeScript creates a temporary wrapper file in the build directory, writes the shebang and the java -cp invocation, and wraps any IOException from temp-file creation or writing in this CodeGenException. The build's code-gen phase then fails.

Source

Thrown at extensions/grpc/codegen/src/main/java/io/quarkus/grpc/codegen/GrpcCodeGen.java:596

        }

        if (OS.current() != OS.WINDOWS) {
            return writeScript(buildDir, pluginPath, "#!/bin/sh\n", ".sh");
        } else {
            return writeScript(buildDir, pluginPath, "@echo off\r\n", ".cmd");
        }
    }

    private static Path writeScript(Path buildDir, Path pluginPath, String shebang, String suffix) throws CodeGenException {
        Path script;
        try {
            script = Files.createTempFile(buildDir, "quarkus-grpc", suffix);
            try (BufferedWriter writer = Files.newBufferedWriter(script)) {
                writer.write(shebang);
                writePluginExeCmd(pluginPath, writer);
            }
        } catch (IOException e) {
            throw new CodeGenException("Failed to create a wrapper script for quarkus-grpc plugin", e);
        }
        if (!script.toFile().setExecutable(true)) {
            throw new CodeGenFailureException("failed to set file: " + script + " executable. Protoc invocation may fail");
        }
        return script;
    }

    private static void writePluginExeCmd(Path pluginPath, BufferedWriter writer) throws IOException {
        writer.write("\"" + io.smallrye.common.process.ProcessUtil.pathOfJava().toString() + "\" -cp \"" +
                pluginPath.toAbsolutePath() + "\" " + quarkusProtocPluginMain);
        writer.newLine();
    }

    private static boolean containsQuarkusKotlin(Collection<ResolvedDependency> dependencies) {
        return dependencies.stream().anyMatch(new Predicate<ResolvedDependency>() {
            @Override
            public boolean test(ResolvedDependency rd) {
                return rd.getGroupId().equalsIgnoreCase("io.quarkus")

View on GitHub (pinned to e1c734241f)

Solutions

Ensure the build output directory (target/) is writable and has free disk space
Run mvn clean / gradle clean and rebuild to remove stale state
Shorten the project path on Windows or enable long-path support
Avoid running parallel builds that clean the same target directory concurrently

Example fix

# before: read-only workspace
ci: ./mvnw clean verify  # target/ mounted ro
# after: use a writable build dir
mvn -Dproject.build.directory=/tmp/build clean verify

Defensive patterns

Strategy: validation

Validate before calling

if (!Files.isWritable(buildDir) || Files.getFileStore(buildDir).getUsableSpace() < 64 * 1024 * 1024) {
    throw new IllegalStateException("Build dir not writable or low on disk: " + buildDir);
}

Try / catch

try {
    build.run();
} catch (CodeGenException e) {
    if (e.getMessage().contains("Failed to create a wrapper script")) {
        exec("mvn clean");
        ensureWritableAndSpace(buildDir);
        build.run();
    }
}

Prevention

Keep the build output directory writable for the build user with free disk space
Avoid concurrent builds that clean the same target directory
Keep project paths short on Windows or enable long-path support
On CI, mount a writable workspace volume for build output

When it happens

Trigger: Code generation where a temp file cannot be created or written under the build directory: read-only build dir, disk full, path too long on Windows, or the directory removed mid-build.

Common situations: Read-only CI workspaces; full disks; Windows MAX_PATH limits from deep project paths; parallel builds that clean target/ while another build writes scripts; restrictive umask or container user mismatch.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/30648df9216e617d. Report an issue: GitHub.