short-circuit formatted_text routine and log error if fragments in first line cannot fit on a new page

3 files changed, 38 insertions, 5 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 717332b0..3d9d39c2 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -5,6 +5,12 @@
 This document provides a high-level view of the changes to the {project-name} by release.
 For a detailed view of what has changed, refer to the {url-repo}/commits/main[commit history] on GitHub.
 
+== Unreleased
+
+Bug Fixes::
+
+* short-circuit formatted_text routine and log error if fragments in first line cannot fit on a new page
+
 == 2.0.0 (2022-05-18) - @mojavelinux
 
 Improvements::
diff --git a/lib/asciidoctor/pdf/ext/prawn/extensions.rb b/lib/asciidoctor/pdf/ext/prawn/extensions.rb
index 141dc5aa..3ec04c5f 100644
--- a/lib/asciidoctor/pdf/ext/prawn/extensions.rb
+++ b/lib/asciidoctor/pdf/ext/prawn/extensions.rb
@@ -431,15 +431,19 @@ module Asciidoctor
 
       # NOTE: override built-in fill_formatted_text_box to insert leading before second line when :first_line is true
       def fill_formatted_text_box text, options
-        if (initial_gap = options[:initial_gap]) && (first_text = text[0]) && first_text[:from_page] != page_number
+        if (initial_gap = options[:initial_gap]) && !text.empty? && text[0][:from_page] != page_number
           self.y -= initial_gap
         end
         merge_text_box_positioning_options options
         box = ::Prawn::Text::Formatted::Box.new text, options
-        remaining_text = box.render
+        remaining_fragments = box.render
         @no_text_printed = box.nothing_printed?
         @all_text_printed = box.everything_printed?
-        remaining_text[0][:from_page] = page_number unless remaining_text.empty?
+        unless remaining_fragments.empty? || (remaining_fragments[0][:from_page] ||= page_number) == page_number
+          log :error, %(cannot fit formatted text on page: #{remaining_fragments.map {|it| it[:image_path] || it[:text] }.join})
+          page.tare_content_stream
+          remaining_fragments = {}
+        end
 
         if @final_gap || (options[:first_line] && !(@no_text_printed || @all_text_printed))
           self.y -= box.height + box.line_gap + box.leading
@@ -447,7 +451,7 @@ module Asciidoctor
           self.y -= box.height
         end
 
-        remaining_text
+        remaining_fragments
       end
 
       # NOTE: override built-in draw_indented_formatted_line to set first_line flag
@@ -483,7 +487,13 @@ module Asciidoctor
         else
           remaining_fragments = box.render dry_run: true
         end
-        remaining_fragments.empty? ? (remaining_fragments = nil) : (remaining_fragments[0][:from_page] = page_number)
+        if remaining_fragments.empty?
+          remaining_fragments = nil
+        elsif (remaining_fragments[0][:from_page] ||= page_number) != page_number
+          log :error, %(cannot fit formatted text on page: #{remaining_fragments.map {|it| it[:image_path] || it[:text] }.join})
+          page.tare_content_stream
+          remaining_fragments = nil
+        end
         if first_line_text_transform
           # NOTE: applying text transform here could alter the wrapping, so isolate first line and shrink it to fit
           first_line_text = (box.instance_variable_get :@printed_lines)[0]
diff --git a/spec/converter_spec.rb b/spec/converter_spec.rb
index 563181df..58c111e8 100644
--- a/spec/converter_spec.rb
+++ b/spec/converter_spec.rb
@@ -500,6 +500,23 @@ describe Asciidoctor::PDF::Converter do
       (expect actual_column).to eql 0
       (expect last_visited_column).to eql 1
     end
+
+    it 'should short-circuit formatted_text and log error if text cannot not fit on new page' do
+      doc = Asciidoctor.load 'text', backend: :pdf
+      last_page = last_page_number = nil
+      (expect do
+        doc.converter.instance_exec do
+          init_pdf doc
+          start_new_page
+          ink_prose 'before'
+          formatted_text [{ text: 'x', ascender: bounds.height, descender: font.descender }]
+          last_page = page
+          last_page_number = page_number
+        end
+      end).to log_message severity: :ERROR, message: 'cannot fit formatted text on page: x'
+      (expect last_page).to be_empty
+      (expect last_page_number).to eql 2
+    end
   end
 
   describe '#next_enclosed_block' do