Fix undefined method `fetch' for nil:NilClass

Fix #307

Author: n-rodriguez

CHANGELOG.md

@@ -12,6 +12,7 @@
 * Raise an error when column's `cond:` setting is unknown
 * Make global search and column search work together (merge: [#350](https://github.com/jbox-web/ajax-datatables-rails/pull/350), fixes: [#258](https://github.com/jbox-web/ajax-datatables-rails/issues/258))
 * Fix: date_range doesn't support searching by a date greater than today (merge: [#351](https://github.com/jbox-web/ajax-datatables-rails/pull/351))
+* Fix: undefined method `fetch' for nil:NilClass (fix: [#307](https://github.com/jbox-web/ajax-datatables-rails/issues/307))
 
 * `AjaxDatatablesRails.config` is removed with no replacement. The gem is now configless :)
 * `AjaxDatatablesRails.config.db_adapter=` is removed and is configured per datatable class now. It defaults to Rails DB adapter. (fixes [#364](https://github.com/jbox-web/ajax-datatables-rails/issues/364))

lib/ajax-datatables-rails/datatable/column.rb

@@ -15,10 +15,14 @@ def initialize(datatable, index, options)
         @datatable   = datatable
         @index       = index
         @options     = options
-        @view_column = datatable.view_columns[options[:data].to_sym]
+        @view_column = datatable.view_columns[column_name]
         validate_settings!
       end
 
+      def column_name
+        @column_name ||= options[:data]&.to_sym
+      end
+
       def data
         options[:data].presence || options[:name]
       end
@@ -87,9 +91,15 @@ def casted_column
       end
 
       def validate_settings!
+        raise AjaxDatatablesRails::Error::InvalidSearchColumn, "Unknown column. Check that `data` field is filled on JS side with the column name" if column_name.empty?
+        raise AjaxDatatablesRails::Error::InvalidSearchColumn, "Check that column '#{column_name}' exists in view_columns" unless valid_search_column?(column_name)
         raise AjaxDatatablesRails::Error::InvalidSearchCondition, cond unless valid_search_condition?(cond)
       end
 
+      def valid_search_column?(column_name)
+        !datatable.view_columns[column_name].nil?
+      end
+
       VALID_SEARCH_CONDITIONS = [
         # String condition
         :start_with, :end_with, :like, :string_eq, :string_in, :null_value,

lib/ajax-datatables-rails/error.rb

@@ -3,6 +3,7 @@
 module AjaxDatatablesRails
   module Error
     class BaseError < StandardError; end
+    class InvalidSearchColumn < BaseError; end
     class InvalidSearchCondition < BaseError; end
   end
 end

spec/ajax-datatables-rails/datatable/column_spec.rb

@@ -202,4 +202,24 @@
       expect(column.send(:type_cast)).to eq('VARCHAR(4000)')
     end
   end
+
+  describe 'when empty column' do
+    before do
+      datatable.params[:columns] = {'0'=>{'data'=>'', 'name'=>'', 'searchable'=>'true', 'orderable'=>'true', 'search'=>{'value'=>'searchvalue', 'regex'=>'false'}}}
+    end
+
+    it 'raises error' do
+      expect { datatable.to_json }.to raise_error(AjaxDatatablesRails::Error::InvalidSearchColumn).with_message("Unknown column. Check that `data` field is filled on JS side with the column name")
+    end
+  end
+
+  describe 'when unknown column' do
+    before do
+      datatable.params[:columns] = {'0'=>{'data'=>'foo', 'name'=>'', 'searchable'=>'true', 'orderable'=>'true', 'search'=>{'value'=>'searchvalue', 'regex'=>'false'}}}
+    end
+
+    it 'raises error' do
+      expect { datatable.to_json }.to raise_error(AjaxDatatablesRails::Error::InvalidSearchColumn).with_message("Check that column 'foo' exists in view_columns")
+    end
+  end
 end