Support `jar` as executable

[koppor]

Currently, gg.cmd does not download a .jar file and executes it with a JDK.

Currently:

c:\Users\olive\bin>.\gg.cmd gh/blazmrak/veles --help
Prep failed: No matching download found for OS: Windows, Arch: X86_64

Expectation: gg.cmd sees that there is only a jar available. Then downloads latest JRE-LTS and executes the jar with that JRE.

Interestingly, at the first call, gg.cmd seems to try to download Java:

c:\Users\olive\bin>.\gg.cmd gh/blazmrak/veles --help
java 25.0.0   Done [00:00:01] [###############################################################################################] 219.46 MiB/219.46 MiB (0.0s)
Prep failed: No matching download found for OS: Windows, Arch: X86_64

(This is kind of sub-issue of #212)

[eirikb]

It should detect Java based on repo language: https://github.com/eirikb/gg/blob/main/src/stage4/src/executors/github.rs#L55
But it seems it doesn't work. On my machine it detect it requires java, but is unable to execute correctly.
Looking at .jar file should also help, at least if it can see the .jar file in the list of assets.

[koppor]

It would be also nice if run supported .jar links. I know that this wish is caused by a bad release management, but I think, its nice for enabling to try out something quickly. Example:

gg.cmd run https://github.com/fredoverflow/karel/raw/refs/heads/release/karel.jar

Current result:

thread 'main' panicked at src\main.rs:509:18:
called `Result::unwrap()` on an `Err` value: "Error: Unable to find executable for custom_command. The tool may not be properly installed or the binary name doesn't match expected patterns."
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The current repository is https://github.com/fredoverflow/karel

[eirikb]

Yeah definitely. I'll look into this soon. I bet fixing the bug is not hard, and pointing to .jar files should be no problem as well.

[eirikb]

@koppor You can test now with latest version