Bring back silencing of errors in blank nodes for backwards compatibility (#1292)

lib/liquid/block_body.rb

@@ -77,7 +77,10 @@ module Liquid
       raise
     rescue ::StandardError => e
       line_number = node.is_a?(String) ? nil : node.line_number
-      output << context.handle_error(e, line_number)
+      error_message = context.handle_error(e, line_number)
+      if node.instance_of?(Variable) || !node.blank? # conditional for backwards compatibility
+        output << error_message
+      end
     end
 
     private def parse_liquid_tag(markup, parse_context)

test/integration/error_handling_test.rb

@@ -261,4 +261,12 @@ class ErrorHandlingTest < Minitest::Test
     assert_equal("Argument error:\nLiquid error (product line 1): argument error", page)
     assert_equal("product", template.errors.first.template_name)
   end
+
+  def test_bug_compatible_silencing_of_errors_in_blank_nodes
+    output = Liquid::Template.parse("{% assign x = 0 %}{% if 1 < '2' %}not blank{% assign x = 3 %}{% endif %}{{ x }}").render
+    assert_equal("Liquid error: comparison of Integer with String failed0", output)
+
+    output = Liquid::Template.parse("{% assign x = 0 %}{% if 1 < '2' %}{% assign x = 3 %}{% endif %}{{ x }}").render
+    assert_equal("0", output)
+  end
 end