withr 2.5.0

• defer() and all local_*() functions now work when run inside of
  a .Rmd. The deferred expressions are executed when knitr exits.

• defer() and local_ functions now work within source().
  The deferred expressions are executed when source() exits.

• with_() and local_() gain a get argument. Supply a getter
  function to create with and local functions that are robust to
  early exits.

  When supplied, this restoration pattern is used:

  old <- get()
  on.exit(set(old))
  set(new)
  action()
  

  Instead of:

  old <- set(new)
  on.exit(set(old))
  action()
  

  This ensures proper restoration of the old state when an early exit
  occurs during set() (for instance when a deprecation warning is
  caught, see #191).

• These with_ and local_ functions are now robust to early exits (see next bullet):

  • _locale()
  • _envvar()
  • _libpaths()
  • _options()
  • _par()
  • _path()
  • _seed()

• with_namespace() and local_namespace() now pass warn.conflicts
  to attach() (@kyleam, #185).

• local_rng_version() and local_seed() no longer warn when
  restoring sample.kind to "Rounding" (#167).

• with_seed() now preserves the current values of RNGkind() (#167).

• with_collate() is no longer affected by the LC_COLLATE
  environment variable set to "C" (#179).

• Local evaluations in the globalenv() (as opposed to top-level
  ones) are now unwound in the same way as regular environments.

• local_tempfile() gains a lines argument so, if desired, you can pre-fill
  the temporary file with some data.