From 6314354fa2f500190ceeecedaf87f6151ebcf346 Mon Sep 17 00:00:00 2001
From: "Ankur Sinha (Ankur Sinha Gmail)" <sanjay.ankur@gmail.com>
Date: Tue, 9 Jun 2026 12:13:18 +0100
Subject: [PATCH] fix(f43): fix incompatibility with expat
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- Fixes rhbz#2370942

Thanks Théodore Papadopoulo for the report and link to the patch.
---
 ...9efca220c9d16a30958e179abae3379d0011.patch | 70 +++++++++++++++++++
 vtk.spec                                      |  4 ++
 2 files changed, 74 insertions(+)
 create mode 100644 db8f9efca220c9d16a30958e179abae3379d0011.patch

diff --git a/db8f9efca220c9d16a30958e179abae3379d0011.patch b/db8f9efca220c9d16a30958e179abae3379d0011.patch
new file mode 100644
index 0000000..0bf534a
--- /dev/null
+++ b/db8f9efca220c9d16a30958e179abae3379d0011.patch
@@ -0,0 +1,70 @@
+From db8f9efca220c9d16a30958e179abae3379d0011 Mon Sep 17 00:00:00 2001
+From: Ben Boeckel <ben.boeckel@kitware.com>
+Date: Mon, 15 Apr 2024 22:22:22 -0400
+Subject: [PATCH] vtkXMLDataParser: track `AppendedData` state explicitly
+
+Newer `libexpat` doesn't like being given the appended data after the
+artificially ended document anymore. Avoid pushing it through to its
+parser.
+
+Fixes: #19258
+---
+ IO/XMLParser/vtkXMLDataParser.cxx | 6 +++++-
+ IO/XMLParser/vtkXMLDataParser.h   | 3 +++
+ 2 files changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/IO/XMLParser/vtkXMLDataParser.cxx b/IO/XMLParser/vtkXMLDataParser.cxx
+index 1f6006d37c2..7d38092fdd7 100644
+--- a/IO/XMLParser/vtkXMLDataParser.cxx
++++ b/IO/XMLParser/vtkXMLDataParser.cxx
+@@ -36,6 +36,7 @@ vtkXMLDataParser::vtkXMLDataParser()
+   this->RootElement = nullptr;
+   this->AppendedDataPosition = 0;
+   this->AppendedDataMatched = 0;
++  this->AppendedDataFound = false;
+   this->DataStream = nullptr;
+   this->InlineDataStream = vtkBase64InputStream::New();
+   this->AppendedDataStream = vtkBase64InputStream::New();
+@@ -88,6 +89,7 @@ void vtkXMLDataParser::PrintSelf(ostream& os, vtkIndent indent)
+ {
+   this->Superclass::PrintSelf(os, indent);
+   os << indent << "AppendedDataPosition: " << this->AppendedDataPosition << "\n";
++  os << indent << "AppendedDataFound: " << this->AppendedDataFound << "\n";
+   if (this->RootElement)
+   {
+     this->RootElement->PrintXML(os, indent);
+@@ -214,7 +216,7 @@ int vtkXMLDataParser::ParsingComplete()
+   // If we have reached the appended data section, we stop parsing.
+   // This prevents the XML parser from having to walk over the entire
+   // appended data section.
+-  if (this->AppendedDataPosition)
++  if (this->AppendedDataPosition || this->AppendedDataFound)
+   {
+     return 1;
+   }
+@@ -433,6 +435,8 @@ int vtkXMLDataParser::ParseBuffer(const char* buffer, unsigned int count)
+     {
+       return 0;
+     }
++
++    this->AppendedDataFound = true;
+   }
+ 
+   return 1;
+diff --git a/IO/XMLParser/vtkXMLDataParser.h b/IO/XMLParser/vtkXMLDataParser.h
+index 1504a4d400b..142bf28327d 100644
+--- a/IO/XMLParser/vtkXMLDataParser.h
++++ b/IO/XMLParser/vtkXMLDataParser.h
+@@ -204,6 +204,9 @@ protected:
+   // How much of the string "<AppendedData" has been matched in input.
+   int AppendedDataMatched;
+ 
++  // Whether AppendedData has been dealt with or not.
++  bool AppendedDataFound;
++
+   // The byte order of the binary input.
+   int ByteOrder;
+ 
+-- 
+GitLab
+
diff --git a/vtk.spec b/vtk.spec
index 8b2f4b2..65b35aa 100644
--- a/vtk.spec
+++ b/vtk.spec
@@ -74,6 +74,10 @@ Patch3: vtk-python3.13.patch
 Patch4: vtk-build.patch
 # Fix Integer Overflow on 32-bit in KissFFT
 Patch5: vtk-CVE-2025-34297.patch
+# Fix expat incompatibility
+# https://bugzilla.redhat.com/show_bug.cgi?id=2370942
+# https://gitlab.kitware.com/vtk/vtk/-/commit/db8f9efca220c9d16a30958e179abae3379d0011
+Patch6: db8f9efca220c9d16a30958e179abae3379d0011.patch
 
 URL: https://vtk.org/