zoo kcl lint --show-code panics on multi-line and non-ASCII findings; zoo kcl lint always exits 0

[sneg55]

zoo kcl lint --show-code panics on multi-line or non-ASCII findings, and zoo kcl lint always exits 0

Context: API Makeathon participant. Found while reviewing the lint command (which runs fully locally, no engine).

1. --show-code panics

src/cmd_kcl.rs:1739-1755:

if self.show_code {
    if start.line != end.line {
        unimplemented!()                          // raw panic, exit 101
    }
    let printable_line = code.lines().collect::<Vec<&str>>()[start.line as usize];
    println!("...", &printable_line[..(start.character as usize)], ...);  // byte-slice by char offset

Two problems:

• Any finding whose span crosses a line boundary hits unimplemented!(), a raw Rust panic with a backtrace, instead of an error or a degraded rendering. The lint engine can produce multi-line spans and nothing upstream filters them.
• start.character / end.character come from to_lsp_range (character offsets), but they are used to byte-slice printable_line. On a line with any multi-byte character before the finding (Ø, µ, a degree sign in a comment), the slice lands mid-codepoint and panics with "byte index is not a char boundary", or underlines the wrong columns.

2. lint always exits 0

CmdKclLint::run returns Ok(()) regardless of how many findings it printed (src/cmd_kcl.rs:1712-1759), so zoo kcl lint always exits 0 and cannot gate CI on lint findings.

Concrete failure

zoo kcl lint --show-code file.kcl on a file with a non-ASCII comment preceding a same-line finding aborts with a panic (exit 101, "please report this" backtrace), reading as a CLI crash rather than a lint result. And a CI job running zoo kcl lint passes even when findings exist.

Verify

Construct a KCL file where a lint finding sits after a // °C comment on the same line and run with --show-code, or code-review that unimplemented!() is reachable. Run zoo kcl lint on a file with findings and check $? (it is 0).

Suggested fix

Handle multi-line spans without panicking, slice by character (or convert LSP offsets to byte offsets) for the underline, and return a nonzero exit when findings are present (or behind a --deny flag).

Environment

Zoo CLI v0.2.184 (33534cd). Reviewed against the current main of KittyCAD/cli.