Both build_node_compilers:entrypoint and firebase_node:nodejs_builder may output node/enter.dart.bootstrap.js
Both build_node_compilers:entrypoint and firebase_node:nodejs_builder may output node/enter.dart.bootstrap.js. Potential outputs must be unique across all builders. See https://github.com/dart-lang/build/blob/master/docs/faq.md#why-do-builders-need-unique-outputsI forked build_node_compilers and updated analyzer to the latest version. I then forked this project and updated the build_node_compiler dependency to my fork's, and then added my firbase_node_dart fork to my project's pubspec.
Running pub run build_runner build --output build in my /functions/ folder yielded that error message.