fix(err,test): preserve argument quoting and exit codes in rtk err/test

[albatrossflyon-coder]

Summary

Fixes #2985.

rtk err <cmd> and rtk test <cmd> build their sh -c/cmd /C command string with argv.join(" "). The OS already splits argv into correct elements by the time this process sees them, but the naive join discards that boundary information. An argument containing shell metacharacters — node -e 'console.log("a")', python3 -c "print(...)" — gets flattened into the join, and the shell re-splits it on those same characters when re-parsing the string.

On the exit-code half: I don't think exit-code propagation itself is actually broken — run_streaming correctly reads and returns the child's real exit status (verified this is the same code path I already fixed for #2994 in #2997). The exit-0 symptom in the issue's repro is what happens when there's no child failure to propagate: the shell's own syntax-error diagnostic looks like a command failure, but the target command was never actually invoked in a form the shell could execute — there's nothing non-zero to report because nothing that ran actually failed. Fixing the quoting fixes this too, verified below.

Fix

Added quote_shell_arg/shell_quote_join to re-quote each argument before joining, so the shell reconstructs the original argument boundaries instead of re-splitting a flattened string.

Windows needed one extra step beyond quoting. std::process::Command's own argument-escaping was re-escaping the already-quoted command string a second time when spawning cmd.exe — corrupting it before cmd.exe ever saw it. Using raw_arg (passes the string through untouched, no extra escaping layer) for the Windows /C invocation fixes that. Without it I could reproduce a different broken-quoting failure than the one reported — same root cause, different platform-specific escaping bug.

Verified live

$ rtk err node -e 'console.log("a")'
[ok] Command completed successfully (no errors)
$ echo $?
0

A genuinely failing command with quotes, semicolons, and parens all in one argument:

$ rtk err node -e 'console.log("before"); process.exit(3)'
[FAIL] Command failed (exit code: 3)
  before
$ echo $?
3

Also confirmed python -c "print('hello world')" and that legitimate shell features (a plain rtk err invocation without special characters) are unaffected.

Testing

• New unit tests: quote_shell_arg leaves safe args unquoted / quotes args with metacharacters / quotes args with spaces; shell_quote_join preserves argument boundaries (the exact regression scenario) / handles empty argv
• cargo test: 2449 passed, 8 ignored, 0 failed
• cargo clippy --all-targets -- -D warnings: clean

Note

I tested this on Windows (not the macOS environment in the original report), so I can't directly confirm the POSIX sh -c branch against a real POSIX shell — quote_shell_arg's non-Windows path uses the standard single-quote-wrap-with-'\''-escape technique, which is the textbook-correct approach for this, but flagging that a maintainer with a Unix box handy might want to double check it directly.

[tapheret2]

Review: fix(err,test): preserve argument quoting and exit codes in rtk err/test

Files: src/cmds/rust/runner.rs, src/main.rs
Size: +118 / -20

Notes

• Static pass on the patch: no obvious blockers from the diff alone.

Thanks @albatrossflyon-coder — independent review on the patch.