mdbook build flag that doesn't implicitly create files and errors if bad path in SUMMARY.md #253
Description
For rustc's CI, we set the filesystem to be mostly read-only. If a rustc docs contributor accidentally adds in an invalid path, we get these obscure read-only errors because mdbook is trying to create a file even though we don't want it to. It'd be helpful if there was a mdbook build flag like --nocreate or --strict that doesn't attempt to create files from SUMMARY.md if they don't exist and instead results in a build error.
Does this sound alright? If so, I can implement this.