Missing values and blank pages when adjusting prose_margin_bottom alongside a for table column type

[myii]

Related issue

May be related to #926.

Asciidoctor file

= Bug: Using `a` for table column type

.Content is not displayed *and* results in blank page(s)
[format="psv", cols="a"]
|===
|
* abc
|===

Theme

---
extends: default
base:
  font_family: M+ 1mn
  ### For testing with `prose_margin_bottom: 0`
  # line_height: 1
prose:
  ### Can get this working with `base_line_height: 1` but with an extra blank page
  # margin_bottom: 0

  ### Content isn't displayed with the default value of `base_line_height`
  # margin_bottom: 1
  margin_bottom: 2

  ### Content is displayed but an extra blank page is still produced
  # margin_bottom: 3
  # margin_bottom: 4
  # margin_bottom: 5

  ### Lowest value that works without issues using the default `base_line_height`
  # margin_bottom: 6

• Another important factor is the font_family that it used; some are affected more adversely than others.

Command

$ asciidoctor-pdf -a pdf-theme=bug_using-type-a-for-table-column.yml bug_using-type-a-for-table-column.adoc

Result

Workaround

Adjust prose_margin_bottom until a suitable value is found where the content is displayed and no extra page is produced.

[mojavelinux]

This turns out to be two separate bugs. First, prawn-table has some rounding errors that cause it to not reserve enough height for the cell. When that happens, the remainder gets thrown onto the next page. Basically, it's just haywire.

The second problem is that our blank page cleanup routine assumes the cursor is on the last page. There are cases, like this one, when it is not. So that requires an additional check.

[mojavelinux]

Thanks for the detailed error report!

[myii]

As mentioned when discussing the commit, this issue appears to be resolved now.