Provide a default line number

lib/cfn-nag/result_view/sarif_results.rb

@@ -64,7 +64,7 @@ def sarif_result(file_name:, violation:, index:)
               uriBaseId: '%SRCROOT%'
             },
             region: {
-              startLine: violation.line_numbers[index]
+              startLine: sarif_line_number(violation.line_numbers[index])
             }
           },
           logicalLocations: [
@@ -77,6 +77,11 @@ def sarif_result(file_name:, violation:, index:)
     }
   end
 
+  # Line number defaults to 1 unless provided with valid number
+  def sarif_line_number(line_number)
+    line_number.nil? || line_number.to_i < 1 ? 1 : line_number.to_i
+  end
+
   def sarif_level(violation_type)
     case violation_type
     when RuleDefinition::WARNING

spec/result_view/sarif_results_spec.rb

@@ -146,4 +146,31 @@
       expect(SarifResults.new.relative_path('spec/test_templates/yaml/vulgar_bad_syntax.yml')).to eq('spec/test_templates/yaml/vulgar_bad_syntax.yml')
     end
   end
+
+  describe '#sarif_line_number' do
+    context 'with nil line number' do
+      it 'should return 1' do
+        expect(SarifResults.new.sarif_line_number(nil)).to eq(1)
+      end
+    end
+    context 'with empty line number' do
+      it 'should return 1' do
+        expect(SarifResults.new.sarif_line_number('')).to eq(1)
+      end
+    end
+    context 'with line number less than 1' do
+      it 'should return 1' do
+        expect(SarifResults.new.sarif_line_number(0)).to eq(1)
+        expect(SarifResults.new.sarif_line_number(-1)).to eq(1)
+        expect(SarifResults.new.sarif_line_number('-1')).to eq(1)
+      end
+    end
+    context 'with positive line number' do
+      it 'should return line number' do
+        expect(SarifResults.new.sarif_line_number(1)).to eq(1)
+        expect(SarifResults.new.sarif_line_number('10')).to eq(10)
+        expect(SarifResults.new.sarif_line_number(100)).to eq(100)
+      end
+    end
+  end
 end