[native-image] confusing error message when output file name matches existing directory

[tednaleid]

I've got a demo repo that shows this issue with graal 1.0.0-rc3 on OSX: https://github.com/tednaleid/graal-issue Just check that out and run https://github.com/tednaleid/graal-issue/blob/master/show-issue.sh

If I run the following command to try to compile a jar in a subdirectory that has the same name as the jar's base name:

native-image -jar graal-issue-core/build/libs/graal-issue-core.jar

it fails with a confusing error message that says

fatal error: java.lang.RuntimeException: java.lang.RuntimeException: host C compiler or linker does not seem to work: java.lang.RuntimeException: returned 1

Buried in a bunch of other stack traces, it eventually says:

ld: can't open output file for writing: /private/tmp/graal-issue/graal-issue-core, errno=21 for architecture x86_64

Which took me far longer to realize than it should have that it was because it was trying to generate a file with the same path as an existing subdirectory in my current directory.

As far as I can tell, there isn't an option in native-image to output the file to a different name. I think there should be clearer upfront detection that the path it is trying to write the binary to isn't valid.

my environment:

java -version
java version "1.8.0_172"
Java(TM) SE Runtime Environment (build 1.8.0_172-b11)
GraalVM 1.0.0-rc3 (build 25.71-b01-internal-jvmci-0.45, mixed mode)

sw_vers
ProductName:	Mac OS X
ProductVersion:	10.13.5
BuildVersion:	17F77

[tednaleid]

Just discovered that you can customize the output file name with -H:Name=my-native-app

[olpaw]

@tednaleid I agree. I will make this error message more reasonable.

[olpaw]

Fixed in 473c771

[tednaleid]

Thanks for the quick fix! I appreciate that the error message also includes the -H:Name suggestion, I bet that'll save some people some time :).