fix: yaml multi-line literals maintain their lines

src/Microsoft.OpenApi.YamlReader/Microsoft.OpenApi.YamlReader.csproj

@@ -33,7 +33,7 @@
           <PrivateAssets>all</PrivateAssets>
         </PackageReference>
 
-        <PackageReference Include="SharpYaml" Version="2.1.3" />
+        <PackageReference Include="SharpYaml" Version="2.1.4" />
         <PackageReference Include="System.Text.Json" Version="[8.0.5,)" />
         <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-hh2w-p6rv-4g7w" />
         <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-8g4q-xg66-9fp4" />

src/Microsoft.OpenApi.YamlReader/YamlConverter.cs

@@ -151,10 +151,19 @@ private static YamlScalarNode ToYamlScalar(this JsonValue val)
                 // Strings that look like numbers, booleans, or null need to be quoted
                 // to preserve their string type when round-tripping
                 var needsQuoting = NeedsQuoting(stringValue);
+
+                var containsNewLine = stringValue.Contains('\n');
+
+                var style = (needsQuoting, containsNewLine) switch
+                {
+                    (true, _) => ScalarStyle.DoubleQuoted,
+                    (false, true) => ScalarStyle.Literal,
+                    (false, false) => ScalarStyle.Plain
+                };
 
                 return new YamlScalarNode(stringValue)
                 {
-                    Style = needsQuoting ? ScalarStyle.DoubleQuoted : ScalarStyle.Plain
+                    Style = style
                 };
             }
 

test/Microsoft.OpenApi.Readers.Tests/YamlConverterTests.cs

@@ -282,6 +282,31 @@ public void BooleanPropertyNamesShouldRemainStringsFromYaml()
         // Then
         Assert.Equal(yamlInput.MakeLineBreaksEnvironmentNeutral(), convertedBackOutput.MakeLineBreaksEnvironmentNeutral());
     }
+
+    [Fact]
+    public void LineBreaksShouldRoundTrip()
+    {
+        var yamlInput =
+        """
+        python: |-
+          from openai import OpenAI
+
+          client = OpenAI(
+              api_key="My API Key",
+          )
+          page = client.beta.assistants.list()
+          page = page.data[0]
+          print(page.id)
+        """;
+        // When
+        var jsonNode = ConvertYamlStringToJsonNode(yamlInput);
+        var convertedBack = jsonNode.ToYamlNode();
+        var convertedBackOutput = ConvertYamlNodeToString(convertedBack);
+
+        // Then
+        Assert.Equal(yamlInput.MakeLineBreaksEnvironmentNeutral(), convertedBackOutput.MakeLineBreaksEnvironmentNeutral());
+    }
+
     private static JsonNode ConvertYamlStringToJsonNode(string yamlInput)
     {
         var yamlDocument = new YamlStream();