Ensure the `read_to_end` buffer always has enough room to fit a single UTF-8 code point - #142872

ChrisDenton wants to merge 1 commit into

Ensure the `read_to_end` buffer always has enough room to fit a single UTF-8 code point#142872
ChrisDenton wants to merge 1 commit into
rust-lang:mainfrom
ChrisDenton:fixup

Avoid unnecessarily short reads in `read_to_end`