In some terminal emulators, writing a character into the last column on a
row causes the terminal to immediately wrap to the beginning of the next
line, even if the very next character in the stream is a hard newline.
That can then lead to errant blank lines in the final output which make
it harder to navigate the visual hierarchy.
As a compromise to avoid this, we'll format our horizontal rules and
paragraphs to one column less than the terminal width. That does mean that
our horizontal rules won't _quite_ cover the whole terminal width, but
it seems like a good compromise in order to get consistent behavior across
a wider variety of terminal implementations.
We now require the output to accept UTF-8 and we can determine how wide
the terminal (if any) is, so here we begin to make use of that for the
"terraform plan" command.
The horizontal rule is now made of box drawing characters instead of
hyphens and fills the whole terminal width.
The paragraphs of text in the output are now also wrapped to fill the
terminal width, instead of the hard-wrapping we did before.
This is just a start down the road of making better use of the terminal
capabilities. Lots of other commands could benefit from updates like these
too.
Martin Atkins