Fix the config suggestion in the warning for $ bundle

* `install_or_cli_help` does not exist for older Bundler like Bundler 2
  and so results in a confusing error on Bundler 2:
  ```
  $ bundle
  Could not find command "".
  ```
* See https://github.com/ruby/rubygems/pull/9136/files#r2592366837
* Merge the behavior of `install_or_cli_help` in `install`.

Author: eregon

bundler/lib/bundler/cli.rb

@@ -120,14 +120,6 @@ def cli_help
       self.class.send(:class_options_help, shell)
     end
 
-    desc "install_or_cli_help", "Tries to run bundle install but prints a summary of bundler commands if there is no Gemfile", hide: true
-    def install_or_cli_help
-      invoke_other_command("install")
-    rescue GemfileNotFound => error
-      Bundler.ui.error error.message, wrap: true
-      invoke_other_command("cli_help")
-    end
-
     def self.default_command(meth = nil)
       return super if meth
 
@@ -136,12 +128,12 @@ def self.default_command(meth = nil)
           In a future version of Bundler, running `bundle` without argument will no longer run `bundle install`.
           Instead, the `cli_help` command will be displayed. Please use `bundle install` explicitly for scripts like CI/CD.
           You can use the future behavior now with `bundle config set default_cli_command cli_help --global`,
-          or you can continue to use the current behavior with `bundle config set default_cli_command install_or_cli_help --global`.
+          or you can continue to use the current behavior with `bundle config set default_cli_command install --global`.
           This message will be removed after a default_cli_command value is set.
         MSG
       end
 
-      Bundler.settings[:default_cli_command] || "install_or_cli_help"
+      Bundler.settings[:default_cli_command] || "install"
     end
 
     class_option "no-color", type: :boolean, desc: "Disable colorization in output"
@@ -287,6 +279,9 @@ def install
       Bundler.settings.temporary(no_install: false) do
         Install.new(options).run
       end
+    rescue GemfileNotFound => error
+      invoke_other_command("cli_help")
+      raise error # re-raise to show the error and get a failing exit status
     end
 
     map aliases_for("install")

bundler/spec/bundler/cli_spec.rb

@@ -100,10 +100,11 @@ def out_with_macos_man_workaround
     end
 
     it "runs bundle install when default_cli_command set to install" do
-      bundle "config set default_cli_command install_or_cli_help"
+      bundle "config set default_cli_command install"
       bundle "", raise_on_error: false
       expect(out).to_not include("In a future version of Bundler")
       expect(err).to include("Could not locate Gemfile")
+      expect(exitstatus).to_not be_zero
     end
   end