When the chunk option autodep = TRUE, all names of objects created in
a chunk will be saved in a file named __objects and all global objects
used in a chunk will be saved to __globals. This function can analyze
object names in these files to automatically build cache dependencies, which
is similar to the effect of the dependson option. It is supposed to be
used in the first chunk of a document and this chunk must not be cached.
dep_auto(path = opts_chunk$get("cache.path"))NULL. The dependencies are built as a side effect.
Path to the dependency file.
dep_prev