From a7e7f6912a7a37d74194a67a4f4b4e7e2ad4d1ac Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Sat, 20 Sep 2025 15:49:23 -0700
Subject: [PATCH] [upstream_utils] Upgrade to Eigen 5.0.0 (#8240)

---
 upstream_utils/eigen.py                            |  4 ++--
 .../native/thirdparty/eigen/include/Eigen/Core     |  3 +++
 .../native/thirdparty/eigen/include/Eigen/Version  | 14 ++++++++++++++
 .../eigen/include/Eigen/src/Core/util/Macros.h     |  8 ++------
 4 files changed, 21 insertions(+), 8 deletions(-)
 create mode 100644 wpimath/src/main/native/thirdparty/eigen/include/Eigen/Version

diff --git a/upstream_utils/eigen.py b/upstream_utils/eigen.py
index 6cb3facfa9..e343251160 100755
--- a/upstream_utils/eigen.py
+++ b/upstream_utils/eigen.py
@@ -77,6 +77,7 @@ def eigen_inclusions(dp: Path, f: str):
         "SparseLU",
         "SparseQR",
         "StdVector",
+        "Version",
         "misc",
         "plugins",
     ]
@@ -144,8 +145,7 @@ def copy_upstream_src(wpilib_root: Path):
 def main():
     name = "eigen"
     url = "https://gitlab.com/libeigen/eigen.git"
-    # master on 2025-09-08
-    tag = "e0a59e5a66e6d16fa93ab4f5e48bf539205e837f"
+    tag = "5.0.0"
 
     eigen = Lib(name, url, tag, copy_upstream_src)
     eigen.main()
diff --git a/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Core b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Core
index 2fedfd3b80..546625bb1f 100644
--- a/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Core
+++ b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Core
@@ -11,6 +11,9 @@
 #ifndef EIGEN_CORE_MODULE_H
 #define EIGEN_CORE_MODULE_H
 
+// Eigen version information.
+#include "Version"
+
 // first thing Eigen does: stop the compiler from reporting useless warnings.
 #include "src/Core/util/DisableStupidWarnings.h"
 
diff --git a/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Version b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Version
new file mode 100644
index 0000000000..de4a594adc
--- /dev/null
+++ b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/Version
@@ -0,0 +1,14 @@
+#ifndef EIGEN_VERSION_H
+#define EIGEN_VERSION_H
+
+// The "WORLD" version will forever remain "3" for the "Eigen3" library.
+#define EIGEN_WORLD_VERSION 3
+// As of Eigen3 5.0.0, we have moved to Semantic Versioning (semver.org).
+#define EIGEN_MAJOR_VERSION 5
+#define EIGEN_MINOR_VERSION 0
+#define EIGEN_PATCH_VERSION 0
+#define EIGEN_PRERELEASE_VERSION "dev"
+#define EIGEN_BUILD_VERSION "master"
+#define EIGEN_VERSION_STRING "5.0.0-dev+master"
+
+#endif  // EIGEN_VERSION_H
diff --git a/wpimath/src/main/native/thirdparty/eigen/include/Eigen/src/Core/util/Macros.h b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/src/Core/util/Macros.h
index 9198555973..35eb161361 100644
--- a/wpimath/src/main/native/thirdparty/eigen/include/Eigen/src/Core/util/Macros.h
+++ b/wpimath/src/main/native/thirdparty/eigen/include/Eigen/src/Core/util/Macros.h
@@ -17,13 +17,9 @@
 // Eigen version and basic defaults
 //------------------------------------------------------------------------------------------
 
-#define EIGEN_WORLD_VERSION 3
-#define EIGEN_MAJOR_VERSION 4
-#define EIGEN_MINOR_VERSION 90
-
 #define EIGEN_VERSION_AT_LEAST(x, y, z) \
-  (EIGEN_WORLD_VERSION > x ||           \
-   (EIGEN_WORLD_VERSION >= x && (EIGEN_MAJOR_VERSION > y || (EIGEN_MAJOR_VERSION >= y && EIGEN_MINOR_VERSION >= z))))
+  (EIGEN_MAJOR_VERSION > x ||           \
+   (EIGEN_MAJOR_VERSION >= x && (EIGEN_MINOR_VERSION > y || (EIGEN_MINOR_VERSION >= y && EIGEN_PATCH_VERSION >= z))))
 
 #ifdef EIGEN_DEFAULT_TO_ROW_MAJOR
 #define EIGEN_DEFAULT_MATRIX_STORAGE_ORDER_OPTION Eigen::RowMajor