CLDC-4270: Add an error for fields with the wrong type for 2026 lettings

app/services/bulk_upload/lettings/year2026/csv_parser.rb

@@ -9,6 +9,8 @@ class BulkUpload::Lettings::Year2026::CsvParser
 
   attr_reader :path
 
+  ROW_PARSER_CLASS = BulkUpload::Lettings::Year2026::RowParser
+
   def initialize(path:)
     @path = path
   end
@@ -34,11 +36,35 @@ class BulkUpload::Lettings::Year2026::CsvParser
     @row_parsers ||= body_rows.map { |row|
       next if row.empty?
 
+      invalid_fields = []
       stripped_row = row[col_offset..]
 
-      hash = Hash[field_numbers.zip(stripped_row)]
+      hash_rows = field_numbers
+                    .zip(stripped_row)
+                    .map do |field, value|
+                      # this is needed as a string passed to an int attribute is by default mapped to '0'.
+                      # this is bad as some questions will accept a '0'. so you could enter something invalid and not be told about it
+                      expected_is_integer = ROW_PARSER_CLASS.attribute_types[field].is_a?(ActiveModel::Type::Integer)
+                      # we must be certain that the user entered a string that cannot be coerced to an integer
+                      actual_is_non_empty_string = value.present? && Integer(value, exception: false).nil? && Float(value, exception: false).nil?
+                      field_is_valid = !(expected_is_integer && actual_is_non_empty_string)
+
+                      correct_value = field_is_valid ? value : nil
+
+                      invalid_fields << field unless field_is_valid
+
+                      [field, correct_value]
+                    end
+
+      hash = Hash[hash_rows]
+
+      row_parser = ROW_PARSER_CLASS.new(hash)
+
+      invalid_fields.each do |field|
+        row_parser.add_invalid_field(field)
+      end
 
-      BulkUpload::Lettings::Year2026::RowParser.new(hash)
+      row_parser
     }.compact
   end
 

app/services/bulk_upload/lettings/year2026/row_parser.rb

@@ -541,6 +541,8 @@ class BulkUpload::Lettings::Year2026::RowParser
       end
     end
 
+    add_errors_for_invalid_fields
+
     @valid = errors.blank?
   end
 
@@ -620,6 +622,10 @@ class BulkUpload::Lettings::Year2026::RowParser
     end
   end
 
+  def add_invalid_field(field)
+    invalid_fields << field
+  end
+
 private
 
   def normalise_case_insensitive_fields
@@ -1098,6 +1104,17 @@ private
     end
   end
 
+  def invalid_fields
+    @invalid_fields ||= []
+  end
+
+  def add_errors_for_invalid_fields
+    invalid_fields.each do |field|
+      errors.delete(field) # take precedence over any other errors as this is a BU format issue
+      errors.add(field, I18n.t("#{ERROR_BASE_KEY}.invalid_option", question: QUESTIONS[field.to_sym]))
+    end
+  end
+
   def field_mapping_for_errors
     {
       lettype: [:field_11],