fix newline not being added correctly when printing to stderr

2 files changed, 4 insertions, 1 deletions

diff --git a/lib/bundler/ui/shell.rb b/lib/bundler/ui/shell.rb
index 24429d1229..81743ede40 100644
--- a/lib/bundler/ui/shell.rb
+++ b/lib/bundler/ui/shell.rb
@@ -105,6 +105,9 @@ module Bundler
       end
 
       def tell_err(message, color = nil, newline = nil)
+        newline = message.to_s !~ /( |\t)\Z/ unless newline
+        message = word_wrap(message) if newline.is_a?(Hash) && newline[:wrap]
+
         buffer = @shell.send(:prepare_message, message, *color)
         buffer << "\n" if newline && !message.to_s.end_with?("\n")
 
diff --git a/spec/bundler/ui/shell_spec.rb b/spec/bundler/ui/shell_spec.rb
index b33cddab86..2db2d28641 100644
--- a/spec/bundler/ui/shell_spec.rb
+++ b/spec/bundler/ui/shell_spec.rb
@@ -42,7 +42,7 @@ RSpec.describe Bundler::UI::Shell do
     context "when stderr flag is enabled" do
       before { bundle "config error_on_stderr true" }
       it "prints to stderr" do
-        expect { subject.error("error!!!") }.to output("\e[31merror!!!\e[0m").to_stderr
+        expect { subject.error("error!!!") }.to output("\e[31merror!!!\e[0m\n").to_stderr
       end
     end
   end