add openSettings option to ignore missing calcChain parts

Author: tomjebo

src/DocumentFormat.OpenXml.Framework/Packaging/OpenSettings.cs

@@ -12,6 +12,7 @@ public class OpenSettings
     {
         private bool? _autoSave;
         private MarkupCompatibilityProcessSettings? _mcSettings;
+        private bool? _ignoreExceptionsOnCalcChainPartMissing;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="OpenSettings"/> class.
@@ -32,6 +33,7 @@ internal OpenSettings(OpenSettings? other)
             MarkupCompatibilityProcessSettings.TargetFileFormatVersions = other.MarkupCompatibilityProcessSettings.TargetFileFormatVersions;
             MaxCharactersInPart = other.MaxCharactersInPart;
             RelationshipErrorHandlerFactory = other.RelationshipErrorHandlerFactory;
+            IgnoreExceptionOnCalcChainPartMissing = other.IgnoreExceptionOnCalcChainPartMissing;
         }
 
         /// <summary>
@@ -77,5 +79,15 @@ public MarkupCompatibilityProcessSettings MarkupCompatibilityProcessSettings
         /// Gets or sets a delegate that is used to create a handler to rewrite relationships that are malformed. On platforms after .NET 4.5, <see cref="Uri"/> parsing will fail on malformed strings.
         /// </summary>
         public Func<OpenXmlPackage, RelationshipErrorHandler>? RelationshipErrorHandlerFactory { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether to ignore an exception if the calcChain part is missing.
+        /// The default value is false which means missing calcChain part will throw an exception upon package open.
+        /// </summary>
+        public bool IgnoreExceptionOnCalcChainPartMissing
+        {
+            get => _ignoreExceptionsOnCalcChainPartMissing ?? false;
+            set => _ignoreExceptionsOnCalcChainPartMissing = value;
+        }
     }
 }

src/DocumentFormat.OpenXml.Framework/Packaging/OpenXmlPartContainer.cs

@@ -1794,17 +1794,18 @@ internal OpenXmlPart CreateOpenXmlPart(string relationshipType)
         /// <param name="loadedParts">Temp collection to detect loaded (shared) parts.</param>
         internal void LoadReferencedPartsAndRelationships(OpenXmlPackage openXmlPackage, OpenXmlPart? sourcePart, RelationshipCollection relationshipCollection, Dictionary<Uri, OpenXmlPart> loadedParts)
         {
-            List<string> partsToIgnore = new()
+            Dictionary<string, bool> partsToIgnore = new()
             {
                 // Fix bug https://github.com/OfficeDev/Open-XML-SDK/issues/1205
-                @"http://schemas.openxmlformats.org/officeDocument/2006/relationships/calcChain",
+                { @"http://schemas.openxmlformats.org/officeDocument/2006/relationships/calcChain", openXmlPackage.OpenSettings.IgnoreExceptionOnCalcChainPartMissing },
 
                 // Fix bug https://github.com/OfficeDev/Open-XML-SDK/issues/1205
-                @"http://schemas.microsoft.com/office/2006/relationships/recovered",
+                { @"http://schemas.microsoft.com/office/2006/relationships/recovered", true },
             };
+
             foreach (var relationship in relationshipCollection)
             {
-                if (partsToIgnore.Contains(relationship.RelationshipType))
+                if (partsToIgnore.ContainsKey(relationship.RelationshipType) && partsToIgnore[relationship.RelationshipType])
                 {
                     continue;
                 }