Provide encoding for scripts

[someth2say]

Hi there!

I have a situation here, and I could use some help to find the best approach.
I have a JBang script that outputs using unicode emoji, for example:

@Command(name = "sk", mixinStandardHelpOptions = true, ...,  footer = "Made with 💘 by GLS Learning Content Services", ... )

Those unicode emojis are UTF8 encoded.
But now, I have a user whose default encoding is US-ASCII, and things started going bananas.

@Command(name = "sk", mixinStandardHelpOptions = true, ...,  footer = "Made with ???? by GLS Learning Content Services", ... )
                                                                                 ^
/....java:72: error: unmappable character (0x9F) for encoding US-ASCII

In plain java, there are two ways for providing the right encoding:

1. Use java -Dfile.encoding=UTF8
   I assumed that I can pass it to JBang via JBANG_JAVA_OPTIONS="-Dfile.encoding=UTF8", but didn´t work.
   AFAICS, it seems that JBang does not honor those java options when compiling the scripts (despite I failed to find the exact place for that).

2. Use JAVA_TOOL_OPTIONS="-Dfile.encoding=UTF8" environment variable.
   This affects the whole JVM, and indeed works fine.
   But, as per JVM definition, this generates stderr messages:

Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8

Unluckily, I cannot suppress nor ignore the messages, hence the script output gets polluted.

My question is: Is there a way to instruct JBang to use the proper encoding when loading script sources?

[quintesse]

Have you tried jbang -D=file.encoding=UTF8? Not sure if it works but it's worth a try.

[someth2say]

No luck.
jbang -D=file.encoding=UTF8 run ... spits an "unknown option".
jbang run -D=file.encoding=UTF8 ... does not barf, but it seems to ignore the -D.

[quintesse]

Can you try adding the line //JAVAC_OPTIONS -encoding=UTF8 to the source file @someth2say ?

[someth2say]

Almost!
With //JAVAC_OPTIONS -encoding=UTF8 I got a compiler error, but //JAVAC_OPTIONS -encoding UTF8 works!
That solves my problem!

Thanks, @quintesse !

[quintesse]

Oop, yes, that was a typo on my part :-)
Ok, glad that works at least. Which means this issue would be useful too: #1397

[maxandersen]

-D should work.

What does --verbose print ?

[quintesse]

Ah, javac doesn't have a generic -D option 😅

[maxandersen]

Sounds like regression to me but not 100% sure.

[maxandersen]

//JAVAC_OPTIONS -Dfile...

Should work.

[quintesse]

For javac it's actually -encoding

[quintesse]

Sounds like regression to me but not 100% sure.

Yeah, I thought so too for a moment, but javac actually only supports 2 very specific -D options. If you try to do something like -Dfoo it throws an error.

Edit: although you can do javac -J-Dfoo=bar, but I don't think we ever did that. It seems somewhat tricky TBH to be passing the same -D options to both the compiler and the runtime.