File option type doesn't work in native

[wirthi]

Hi,

tl;dr: I believe you are missing native reflection configuration for at least ch.qos.logback.classic.joran.SerializedModelConfigurator for a Spring Shell app to properly work with the native compile feature.

I have used Spring Initializr to create a Spring Boot 3.2.0 app and included Spring Shell as (only) dependency. Java 21, Maven.

demo.zip
demoWithNativeBuildTools.zip (edit: have added this file that includes the proper config in pom.xml)

When the native compile feature is used (GraalVM) on the generated application (without modifications, except adding native-build-tools configuration), an executable is successfully generated. That executable starts, but fails with a NullPointerException (in the constructor of FileInputStream) on e.g. this command:

shell --file AValidFileName

The NPE is not of relevance, it is a consequence of the actual problem: there is incomplete configuration for the reflection at runtime. Using the -H:ThrowMissingRegistrationErrors=true option of GraalVM native-image (23.1 or later) I see the following problem (note: this is print when executing the generated image):
Exception in thread "main" org.graalvm.nativeimage.MissingReflectionRegistrationError: The program tried to reflectively access class ch.qos.logback.classic.joran.SerializedModelConfigurator without it being registered for runtime reflection. Add ch.qos.logback.classic.joran.SerializedModelConfigurator to the reflection metadata to solve this problem. See https://www.graalvm.org/latest/reference-manual/native-image/metadata/#reflection for help.
This message typically means that this dependency is using reflection, but you don't provide reflection configuration, so native-image generates an image that can only fail when this codepath is taken - it throws the NullPointerException.

Note:

• I did add the native-build-tools plugin and metadataRepository config as described in your documentation. This is NOT in the attached file however.
• ./mvnw package -Pnative as listed in the documentation does not trigger a native compile for me. I am using ./mvnw -Pnative native:compile instead.

(discussed in https://graalvm.slack.com/archives/GPEQFN084/p1703162180614929)

Thanks,
Christian Wirth
GraalVM Native Image

[jvalkeal]

That slack link(is it on channel I don't have access?) is not working for me so I can't see what is the discussion. Looks like actual code giving some trouble is not part of the zips you included.

[sdeleuze]

It is on GraalVM Slack, I will share with you the related discussion.

[jvalkeal]

I got more details from a slack thread. It was referring to built-in script command.

[jvalkeal]

I was looking the root cause of this which seems to be a failure of spring's ConversionServicefrom String to a File. spring-shell currently relies on FormattingConversionService and goes to ObjectToObjectConverter and creates File based on a given option value. This doesn't seem to work out-of-the-box with spring-boot with graal.

If I replace to use boot's ApplicationConversionService which registers its own StringToFileConverter this String to File conversion starts to work just fine under graal.

Essentially under graal:

DefaultConversionService cs = new DefaultConversionService();
// canConvert is false
boolean canConvert = cs.canConvert(String.class, File.class);