fix: added some error handling for YAML headers

src/Nitride.Yaml/ParseYamlHeader.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
@@ -30,6 +31,8 @@ public class ParseYamlHeader<TModel> : OperationBase
         this.RemoveHeader = true;
     }
 
+    public Func<Entity, string, Exception, ParseYamlHeaderErrorHandling>? EntityError { get; set; }
+
     /// <summary>
     /// Gets or sets a value indicating whether the header should be removed
     /// and the text content be removed.
@@ -52,10 +55,18 @@ public class ParseYamlHeader<TModel> : OperationBase
         // Process through the files. We only care about the text ones
         // and we'll put a default TModel in for those that don't have a
         // header.
-        return input.SelectEntity<ITextContent>(
-            (
-                entity,
-                content) => this.Parse(entity, content, deserializer));
+        return input
+            .SelectEntity<ITextContent>(
+                (
+                    entity,
+                    content) => this.Parse(entity, content, deserializer));
+    }
+
+    public ParseYamlHeader<TModel> WithEntityError(Func<Entity, string, Exception, ParseYamlHeaderErrorHandling>? value)
+    {
+        this.EntityError = value;
+
+        return this;
     }
 
     /// <summary>
@@ -138,8 +149,24 @@ public class ParseYamlHeader<TModel> : OperationBase
 
         // Pull out the model so we can append it later.
         string yaml = buffer.ToString();
+        TModel? model;
 
-        TModel? model = deserializer.Deserialize<TModel>(yaml);
+        try
+        {
+            model = deserializer.Deserialize<TModel>(yaml);
+        }
+        catch (Exception exception)
+        {
+            ParseYamlHeaderErrorHandling disposition = this.EntityError?.Invoke(entity, yaml, exception)
+                ?? ParseYamlHeaderErrorHandling.Throw;
+
+            if (disposition == ParseYamlHeaderErrorHandling.Ignore)
+            {
+                return entity;
+            }
+
+            throw;
+        }
 
         // If we are not removing the header, then we're done.
         if (!this.RemoveHeader)

src/Nitride.Yaml/ParseYamlHeaderErrorHandling.cs

@@ -0,0 +1,14 @@
+namespace Nitride.Yaml;
+
+public enum ParseYamlHeaderErrorHandling
+{
+    /// <summary>
+    /// Throw an exception if an error happens.
+    /// </summary>
+    Throw,
+
+    /// <summary>
+    /// If an error happens, then include without additional processing.
+    /// </summary>
+    Ignore,
+}