readr v1.3.1

Breaking Changes

Blank line skipping

readr's blank line skipping has been modified to be more consistent and to
avoid edge cases that affected the behavior in 1.2.0. The skip parameter now
behaves more similar to how it worked previous to readr 1.2.0, but in addition
the parameter skip_blank_rows can be used to control if fully blank lines are
skipped. (#923)

tibble data frame subclass

readr 1.3.0 returns results with a spec_tbl_df subclass. This differs from a
regular tibble only that the spec attribute (which holds the column
specification) is lost as soon as the object is subset (and a normal tbl_df
object is returned).

Historically tbl_df's lost their attributes once they were subset. However
recent versions of tibble retain the attributes when subetting, so the
spec_tbl_df subclass is needed to ensure the previous behavior.

This should only break compatibility if you are explicitly checking the class
of the returned object. A way to get backwards compatible behavior is to
call subset with no arguments on your object, e.g. x[].

Bugfixes

• hms objects with NA values are now written without whitespace padding (#930).
• read_*() functions now return spec_tbl_df objects, which differ from
  regular tbl_df objects only in that the spec attribute is removed (and
  they are demoted to regular tbl_df objects) as soon as they are subset
  (#934).
• write_csv2() now properly respects the na argument (#928)
• Fixes compilation with multiple architectures on linux (#922).
• Fixes compilation with R < 3.3.0