resolves #607 don't crash if table is empty and warn (PR #1538)

CHANGELOG.adoc

@@ -26,6 +26,7 @@ For a detailed view of what has changed, refer to the {uri-repo}/commits/master[
 * if path of missing font is absolute, don't suggest that it was not found in the fontsdir
 * allow use of style "regular" as alias for "normal" when defining font
 * emit warning in verbose mode if glyph cannot be found in fallback font (#1529)
+* don't crash if table is empty and warn (#607)
 * only emit warning when non-WINANSI character is used with AFM font if verbose mode is enabled
 * do not emit warning when non-WINANSI character is used with AFM font inside scratch document
 * do not emit log messages from scratch document

lib/asciidoctor/pdf/converter.rb

@@ -2039,7 +2039,10 @@ def convert_table node
         end
 
         # NOTE: Prawn aborts if table data is empty, so ensure there's at least one row
-        table_data = ::Array.new(node.columns.size) { { 'content' => '' } } if table_data.empty?
+        if table_data.empty?
+          logger.warn message_with_context 'no rows found in table', source_location: node.source_location
+          table_data << ::Array.new([node.columns.size, 1].max) { { content: '' } }
+        end
 
         border_width = {}
         table_border_color = theme.table_border_color || theme.table_grid_color || theme.base_border_color

lib/asciidoctor/pdf/ext/asciidoctor/logging_shim.rb

@@ -25,5 +25,9 @@ module Logging
     def logger
       StubLogger
     end
+
+    def message_with_context text, _context = {}
+      text
+    end
   end
 end

spec/spec_helper.rb

@@ -613,11 +613,14 @@ def compute_image_differences reference, actual, difference = nil
     result = false
     if (messages = logger.messages).size == 1
       if (message = messages[0])[:severity] == expected[:severity]
+        if Hash === (message_text = message[:message])
+          message_text = message_text[:text]
+        end
         if Regexp === (expected_message = expected[:message])
-          result = true if expected_message.match? message[:message]
+          result = true if expected_message.match? message_text
         elsif expected_message.start_with? '~'
-          result = true if message[:message].include? expected_message[1..-1]
-        elsif message[:message] === expected_message
+          result = true if message_text.include? expected_message[1..-1]
+        elsif message_text === expected_message
           result = true
         end
       end

spec/table_spec.rb

@@ -3,6 +3,30 @@
 require_relative 'spec_helper'
 
 describe 'Asciidoctor::PDF::Converter - Table' do
+  it 'should not crash if table has no rows' do
+    (expect do
+      pdf = to_pdf <<~'EOS', analyze: :line
+      |===
+      |===
+      EOS
+
+      (expect pdf.lines).to have_size 4
+    end).to not_raise_exception & (log_message severity: :WARN, message: 'no rows found in table')
+  end
+
+  it 'should not crash if cols and table cells are mismatched' do
+    (expect do
+      pdf = to_pdf <<~'EOS', analyze: :line
+      [cols="1,"]
+      |===
+      | cell
+      |===
+      EOS
+
+      (expect pdf.lines).to have_size 8
+    end).to not_raise_exception & (log_message severity: :WARN, message: 'no rows found in table')
+  end
+
   context 'Decoration' do
     it 'should apply frame all and grid all by default' do
       pdf = to_pdf <<~'EOS', analyze: :line