[ruby/rubygems] Show only error message on attestation failure unless verbose

When auto-attestation fails, the warning previously included
e.full_message with a full backtrace that could be noisy and expose
local paths. Now only e.message is shown by default, and the full
backtrace is included only when Gem.configuration.really_verbose is set.

ruby/rubygems@4a4d9b8911

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

lib/rubygems/commands/push_command.rb

@@ -135,7 +135,13 @@ def send_push_request_with_attestation(name, args)
       request.add_field "Authorization", api_key
     end
   rescue StandardError => e
-    alert_warning "Failed to push with attestation, retrying without attestation.\n#{e.full_message}"
+    message = "Failed to push with attestation, retrying without attestation.\n"
+    message += if Gem.configuration.really_verbose
+      e.full_message
+    else
+      e.message
+    end
+    alert_warning message
     send_push_request_without_attestation(name, args)
   end