The "nonce" CSP feature has been never been properly tested and is not
on track to be enabled at WMF or in MW by default. The use of
nonce-protected eval is not particularly meaningful. It is trivially
bypassed by mw.loader.implement, mw.loader.store, or importScript();
all of which allow any code to be executed directly, or to be stored
and loaded from a first-party origin.
The "nonce" feature is not required for the T208188 roadmap, and with
change I51b8535b2b21a3 there is now also a (small) performance reason
to keep this disabled long-term.
Until and unless there is a plan for enabling this particular aspect
of CSP, we might as well remove it so that we don't waste time our
time building abstraction layers and satisfying dependency injection
through many years for something that might never be used.
Note that this does not remove CSP support from ResourceLoader, and
does not take away from the future of enabling CSP in MediaWiki to
e.g. strictly block third-party scripts, or to require domains to
opt-in by site config or user pref (T208188).
Change-Id: I5a176c41a06a484a11e64bdacdc42b40811fe72e
b28faecb2b