Fix reflection-based XmlSerializer to support XmlSchemaObject-derived types#129490
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StephenMolloy merged 2 commits intoJun 30, 2026
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… types Fixes two related bugs exposed when deserializing XmlSchemaObject-derived types with the reflection-based XmlSerializer: 1. ReflectionXmlSerializationReader.WriteLiteralStructMethod threw NotImplementedException when the target type was assignable from XmlSchemaObject. The IL-based reader sets DecodeName = false instead, which prevents XmlConvert.DecodeName from corrupting schema names that contain colons (e.g. xs:string). This change matches that behavior. 2. The member-flushing loop unconditionally called GetSetMemberValueDelegate for all collection-type members, including read-only collection properties like XmlSchemaElement.Constraints. Calling PropertyInfo.SetValue on a property with no setter threw ArgumentException. The fix detects read-only properties (no setter) and adds items directly into the existing collection instance returned by the getter, using AddObjectsIntoTargetCollection. Fixes dotnet#1399 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
This PR improves the reflection-based XmlSerializer deserialization path for XmlSchemaObject-derived types by aligning key behaviors with the IL-generated reader and adding regression coverage in the XmlSerializer test suite.
Changes:
- In the reflection reader, disable
DecodeNamewhen deserializingXmlSchemaObject-derived types (matching the IL-generated reader’s behavior). - Fix deserialization for collection members backed by read-only properties (no setter) by populating the existing collection instance instead of trying to assign a new one.
- Add/relocate tests to cover
XmlSchemaandXmlSchemaObjectround-tripping scenarios (including read-only collection properties likeXmlSchemaElement.Constraints) under ReflectionOnly mode.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/libraries/System.Private.Xml/tests/XmlSerializer/XmlSerializerTests.RuntimeOnly.cs | Adds regression tests for XmlSchema / XmlSchemaObject round-tripping, including read-only collection properties. |
| src/libraries/System.Private.Xml/tests/XmlSerializer/XmlSerializerTests.Internal.cs | Removes the Xml_XmlSchema test from the internal-only bucket now that ReflectionOnly behavior is covered. |
| src/libraries/System.Private.Xml/src/System/Xml/Serialization/ReflectionXmlSerializationReader.cs | Implements the reflection-reader fixes for XmlSchemaObject name decoding and read-only collection property population. |
This was referenced Jun 17, 2026
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… types (#129490) Fixes two related bugs exposed when deserializing XmlSchemaObject-derived types with the reflection-based XmlSerializer: 1. ReflectionXmlSerializationReader.WriteLiteralStructMethod threw NotImplementedException when the target type was assignable from XmlSchemaObject. The IL-based reader sets DecodeName = false instead, which prevents XmlConvert.DecodeName from corrupting schema names that contain colons (e.g. xs:string). This change matches that behavior. 2. The member-flushing loop unconditionally called GetSetMemberValueDelegate for all collection-type members, including read-only collection properties like XmlSchemaElement.Constraints. Calling PropertyInfo.SetValue on a property with no setter threw ArgumentException. The fix detects read-only properties (no setter) and adds items directly into the existing collection instance returned by the getter, using AddObjectsIntoTargetCollection. Fixes #1399 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Fixes two related bugs exposed when deserializing XmlSchemaObject-derived types with the reflection-based XmlSerializer:
ReflectionXmlSerializationReader.WriteLiteralStructMethod threw NotImplementedException when the target type was assignable from XmlSchemaObject. The IL-based reader sets DecodeName = false instead, which prevents XmlConvert.DecodeName from corrupting schema names that contain colons (e.g. xs:string). This change matches that behavior.
The member-flushing loop unconditionally called GetSetMemberValueDelegate for all collection-type members, including read-only collection properties like XmlSchemaElement.Constraints. Calling PropertyInfo.SetValue on a property with no setter threw ArgumentException. The fix detects read-only properties (no setter) and adds items directly into the existing collection instance returned by the getter, using AddObjectsIntoTargetCollection.
Fixes #1399