"bad array subscript" error

[sanjioh]

Steps to reproduce the behavior

rbenv install 2.7.8

Expected vs. actual behavior

I get the error /usr/local/bin/ruby-build: line 1158: versions: bad array subscript, right after issuing the command, which I suppose should not happen.
The error is not blocking (build completes successfully).

Logs

$ ruby-build --version
ruby-build 20241017

This happens on an Intel Mac with macOS 14.7, ruby-build installed from Homebrew.

[mislav]

Thank you for reporting. This is strange, and I'm glad the error is at least non-fatal.

If you paste the following code into a bash shell, what does it output? (You could paste it into zsh too; it will likely work.)

  brew list 2>/dev/null | grep '^openssl@' | while read -r formula; do
    prefix="$(brew --prefix "$formula" 2>/dev/null || true)"
    [ -n "$prefix" ] || continue
    version="$("$prefix"/bin/openssl version 2>/dev/null | sed -n 's/OpenSSL \([0-9][0-9.]*\).*/\1/p')"
    [ -z "$version" ] || printf '%s %s %s\n' "$formula" "$version" "$prefix"
  done

[sanjioh]

Hi, thanks for replying.

The output is:

openssl@3 3.3.2 /usr/local/opt/openssl@3

[mislav]

Thanks for checking. That looks okay, so I actually don't know what triggers the "bad array subscript" error. However, I do think that ruby-build is trying to access an array at index -1 somehow, so I could add a guard around that, even if I don't understand how that index happened to be.

ruby-build/bin/ruby-build

Lines 1155 to 1158 in 572dd65

	versions=( $(awk '{print $2}' <<<"$brew_installs" | sort_versions) )
	local index="${#versions[@]}"
	while [ $((index--)) -ge 0 ]; do
	homebrew_version="$(normalize_semver "${versions[index]}")"

[mislav]

Another "bad array subscript" error spotted in the wild: #2387 (comment)