Describe the problem as clearly as you can

When Ruby is installed via mise (or any setup that compiles Ruby with --enable-load-relative), running bundle exec <command> fails with:

No such file or directory - <command> (Errno::ENOENT)

This happens when BUNDLE_PATH is set to vendor/bundle (e.g. via bundle config set path vendor/bundle).

Root cause

When Ruby is built with --enable-load-relative, RubyGems generates binstubs with a #!/bin/sh wrapper instead of #!/usr/bin/env ruby:

#!/bin/sh
# -*- ruby -*-
_=_\
=begin
bindir="${0%/*}"
exec "$bindir/ruby" "-x" "$0" "$@"
=end

When BUNDLE_PATH=vendor/bundle, Bundler::SharedHelpers#set_path prepends vendor/bundle/ruby/X.Y.Z/bin to PATH. During bundle exec, Bundler.which finds the binstub under that vendor bin directory first. Because its shebang is #!/bin/sh, ruby_shebang? returns false and Bundler falls back to Kernel.exec. The OS then runs the shell wrapper, which tries to find ruby at $bindir/ruby — i.e. inside vendor/bundle/.../bin/ — where no ruby binary exists, and the command fails.

Steps to reproduce

1. Install Ruby via mise (or compile Ruby with --enable-load-relative)
2. Create a Rails (or any Bundler-managed) project with a bin/ directory containing binstubs (e.g. bin/rails)
3. Configure BUNDLE_PATH=vendor/bundle:

   bundle config set path vendor/bundle
   

4. Run bundle install
5. Run bundle exec rails (or any binstubbed command)

What were you expecting to happen?

bundle exec rails should run successfully.

What happened instead?

Errno::ENOENT: No such file or directory - rails

Why the project bin/ directory fixes it

Project binstubs under bin/ (generated by bundle binstubs) use #!/usr/bin/env ruby, so ruby_shebang? returns true and Bundler uses load-based execution instead of falling back to kernel_exec. Prepending the project bin/ to PATH before the vendor bin path ensures Bundler.which finds the correct binstub first.

Environment

$ mise --version
# (any recent version)
$ ruby --version
# Ruby built with --enable-load-relative
$ bundle --version
# Bundler 2.x or later
$ bundle config path
# vendor/bundle

Related

• Related to Bundler tries to use wrong version of ruby #8441 (different distro, same shebang class of issue)
• Previous --enable-load-relative binstub issue: Binstub installation conflicts when ruby configured with --enable-load-relative #2955