Sadly I am now finding this rather irritating when trying to work on jruby-rack, since I need to change warbler version constraints to verify if warbler works OK with unreleased jruby-rack 1.3. Pointing examples to a warbler git branch was convenient.

For some reason I can't get warbler to work within bundler off either a local path or a locally built gem either (failures either during bundle exec due to missing executable, or at runtime), so running out of options. :-/

Edit: OK, I see part of the the problem now; need to structure Gemfile differently to avoid require of local gems during Rails startup, as warbler doesn't "fix" these kinds of issues in your Gemfile for you, or warn you about problems with the generated war when referring to git and path sourced gems. Broadly related to #165 and a number of duplicates.

But still get the below when trying to use off a locally built warbler gem (rather than a local git reference)

bundler: failed to load command: warble (/Users/chad/.local/share/mise/installs/ruby/jruby-10.0.2.0/lib/ruby/gems/shared/bin/warble)
Gem::Exception: can't find executable warble for gem warbler
      replace_bin_path at /Users/chad/.local/share/mise/installs/ruby/jruby-10.0.2.0/lib/ruby/stdlib/bundler/rubygems_integration.rb:241
     activate_bin_path at /Users/chad/.local/share/mise/installs/ruby/jruby-10.0.2.0/lib/ruby/stdlib/rubygems.rb:288
                <main> at /Users/chad/.local/share/mise/installs/ruby/jruby-10.0.2.0/lib/ruby/gems/shared/bin/warble:25
                  load at org/jruby/RubyKernel.java:1212

Edit 2: OK, second mystery solved, this is a bundler problem due to bundling into a non-vendor directory, and getting confused across multiple jruby versions. :-/