To add a bit more context: the issue is arising while using Yarn v2's PnP functionality, which also patches fs. As I understand it, Yarn does this in order to transparently support its zipped-up (i.e., non-node_modules) storage of dependencies, while allowing arbitrary packages to read the zipped-up files using normal fs calls. Since those Yarn-internal implementations of copyFile (and other functions) use other fs methods directly (bypassing graceful-fs), they can run into EMFILE errors. See @yarnpkg/fslib for details.

Wrapping the "outer" copyFile call in graceful-fs would provide an opportunity to handle the EMFILE errors and retry.

@ramosbugs @isaacs The API fs.copyFile has 4 parameters, see:
https://nodejs.org/docs/latest-v8.x/api/fs.html#fs_fs_copyfile_src_dest_flags_callback
Fix at #202 .