Issue #20700 has been updated by nobu (Nobuyoshi Nakada). Status changed from Open to Feedback First of all, not all operating systems consider a line that doesn't end with a newline to be a shebang. For example, a file with `"#!/x\n"` fails as "cannot execute: required file not found" both on Linux and macOS. However, a file with `"#!/x"`, no newline, just runs silently on macOS while fails on Linux as well as the above. In addition, prism does not consider a line like macOS. ```shell-session $ echo -ne $'#!ruby -Ex' | ruby -wc ruby: unknown encoding name - x (RuntimeError) bash: exit 1 ``` ```shell-session $ echo -ne $'#!ruby -Ex' | ruby -wc --parser=prism Syntax OK ``` ---------------------------------------- Bug #20700: `warn_cr_in_shebang()` doesn't fire if there's no `\n` https://bugs.ruby-lang.org/issues/20700#change-109546 * Author: AMomchilov (Alexander Momchilov) * Status: Feedback * ruby -v: ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- The `warn_cr_in_shebang()` function looks for `\r\n` together, but the `\r` should emit a warning, regardless if there's also a `\n` or not. ```ruby #!/usr/bin/ruby require "tempfile" require "open3" def run_rb(ruby_src) puts "===== Output of #{ruby_src.inspect}:" Tempfile.create("script.rb") do |f| f.print(ruby_src) f.close stdout_and_stderr_str, status = Open3.capture2e("/opt/rubies/3.3.4/bin/ruby", f.path) raise unless status.success? puts stdout_and_stderr_str end end run_rb("#!ruby") # ✅ no warning run_rb("#!ruby\r") # ❌ no warning! run_rb("#!ruby\r\n") # ✅ warns run_rb("#!ruby -Eutf-8\r\n123") # ✅ warns ``` -- https://bugs.ruby-lang.org/