From 235eb3c83ca731e94ced4e08763dde61cd4be473 Mon Sep 17 00:00:00 2001
From: Andrej730 <azhilenkov@gmail.com>
Date: Thu, 18 Sep 2025 12:35:30 +0500
Subject: [PATCH] build-all.py - use find_package for eigen3

---
 cmake/CMakeLists.txt |  4 +++-
 nix/build-all.py     | 15 ++++++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 15cf0f8f90..81a63615ba 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -863,7 +863,9 @@ endif(MSVC)
 # Ensure other dependencies are provided.
 if(NOT EXISTS "${EIGEN_DIR}")
     find_package(Eigen3 CONFIG)
-    if(NOT Eigen3_DIR)
+    if(Eigen3_DIR)
+        message(STATUS "Eigen3: found config at '${Eigen3_DIR}'.")
+    else()
         message(
             FATAL_ERROR
             "EIGEN_DIR is not provided or provided folder doesn't exist (current value: '${EIGEN_DIR}'). "
diff --git a/nix/build-all.py b/nix/build-all.py
index 03c40d2541..34e44dd223 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -135,6 +135,7 @@ JSON_VERSION = "v3.6.1"
 OCE_VERSION = "0.18.3"
 OCCT_VERSION = "7.8.1"
 BOOST_VERSION = "1.86.0"
+EIGEN_VERSION = "3.3.9"
 PCRE_VERSION = "8.41"
 PCRE2_VERSION = "10.32"
 LIBXML2_VERSION = "2.13.8"
@@ -750,8 +751,16 @@ if "json" in targets:
         urlretrieve(json_url, json_install_path)
 
 if "eigen" in targets:
-    git_clone_or_pull_repository(
-        "https://gitlab.com/libeigen/eigen.git", f"{DEPS_DIR}/install/eigen-3.3.9", revision="3.3.9"
+    dependency_name = f"eigen-install-{EIGEN_VERSION}"
+    build_dependency(
+        name=f"{dependency_name}",
+        mode="cmake",
+        # We add '-install-' in the middle, so it won't be confused with git repo we used previously.
+        build_tool_args=[
+            f"-DCMAKE_INSTALL_PREFIX={DEPS_DIR}/install/{dependency_name}",
+        ],
+        download_url=f"https://gitlab.com/libeigen/eigen/-/archive/{EIGEN_VERSION}/",
+        download_name=f"eigen-{EIGEN_VERSION}.tar.gz",
     )
 
 if "pcre" in targets:
@@ -1108,7 +1117,6 @@ cmake_args = [
     "-DBUILD_SHARED_LIBS=" + OFF_ON[not BUILD_STATIC],
     "-DGLTF_SUPPORT=ON",
     f"-DJSON_INCLUDE_DIR={DEPS_DIR}/install/json",
-    f"-DEIGEN_DIR={DEPS_DIR}/install/eigen-3.3.9",
     "-DBoost_NO_BOOST_CMAKE=On",
     "-DADD_COMMIT_SHA=" + ("On" if ADD_COMMIT_SHA else "Off"),
     "-DVERSION_OVERRIDE=" + ("On" if ADD_COMMIT_SHA else "Off"),
@@ -1116,6 +1124,7 @@ cmake_args = [
 """Default CMake args to use for all CMake configs."""
 cmake_args_prefix_path: list[str] = [
     f"{DEPS_DIR}/install/boost-{BOOST_VERSION}",
+    f"{DEPS_DIR}/install/eigen-install-{EIGEN_VERSION}",
 ]