From f672af7ff7b1c813f445de03f03dceaf49acf24b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20Fr=C3=B6hlich?=
 <christophfroehlich@users.noreply.github.com>
Date: Thu, 12 Mar 2026 08:44:48 +0100
Subject: [PATCH] Use libexpected-dev instead of tl_expected (#322)

---
 README.md                                           |  2 +-
 .../example_validators.hpp                          |  2 +-
 .../cmake/generate_parameter_library.cmake          | 13 ++++++++++++-
 .../generate_parameter_library-extras.cmake         |  4 ++++
 generate_parameter_library/package.xml              |  5 +++++
 5 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 2c10e83f..79de4741 100644
--- a/README.md
+++ b/README.md
@@ -296,7 +296,7 @@ Here is an example custom validator.
 #include <rclcpp/rclcpp.hpp>
 
 #include <fmt/core.h>
-#include <tl_expected/expected.hpp>
+#include <tl/expected.hpp>
 
 namespace my_project {
 
diff --git a/example/include/generate_parameter_library_example/example_validators.hpp b/example/include/generate_parameter_library_example/example_validators.hpp
index 31a8f897..fb511a91 100644
--- a/example/include/generate_parameter_library_example/example_validators.hpp
+++ b/example/include/generate_parameter_library_example/example_validators.hpp
@@ -33,7 +33,7 @@
 #include <string>
 
 #include <rclcpp/rclcpp.hpp>
-#include <tl_expected/expected.hpp>
+#include <tl/expected.hpp>
 
 namespace custom_validators {
 
diff --git a/generate_parameter_library/cmake/generate_parameter_library.cmake b/generate_parameter_library/cmake/generate_parameter_library.cmake
index b047ec47..0e7ca5a6 100644
--- a/generate_parameter_library/cmake/generate_parameter_library.cmake
+++ b/generate_parameter_library/cmake/generate_parameter_library.cmake
@@ -96,10 +96,21 @@ macro(generate_parameter_library LIB_NAME YAML_FILE)
     rclcpp_lifecycle::rclcpp_lifecycle
     rsl::rsl
     tcb_span::tcb_span
+    tl::expected
+    # for backward compatibility
+    # remove once this redirection is removed
+    # https://github.com/PickNikRobotics/cpp_polyfills/pull/12
     tl_expected::tl_expected
   )
   install(DIRECTORY ${LIB_INCLUDE_DIR} DESTINATION include)
-  ament_export_dependencies(fmt parameter_traits rclcpp rclcpp_lifecycle rsl tcb_span tl_expected)
+  ament_export_dependencies(
+    fmt parameter_traits rclcpp rclcpp_lifecycle rsl tcb_span
+    tl-expected
+    # for backward compatibility
+    # remove once this redirection is removed
+    # https://github.com/PickNikRobotics/cpp_polyfills/pull/12
+    tl_expected
+  )
 endmacro()
 
 
diff --git a/generate_parameter_library/generate_parameter_library-extras.cmake b/generate_parameter_library/generate_parameter_library-extras.cmake
index 452030d4..05d39c8d 100644
--- a/generate_parameter_library/generate_parameter_library-extras.cmake
+++ b/generate_parameter_library/generate_parameter_library-extras.cmake
@@ -32,6 +32,10 @@ find_package(rclcpp REQUIRED)
 find_package(rsl REQUIRED)
 find_package(rclcpp_lifecycle REQUIRED)
 find_package(tcb_span REQUIRED)
+find_package(tl-expected REQUIRED)
+# for backward compatibility
+# remove once this redirection is removed
+# https://github.com/PickNikRobotics/cpp_polyfills/pull/12
 find_package(tl_expected REQUIRED)
 
 include("${generate_parameter_library_DIR}/generate_parameter_library.cmake")
diff --git a/generate_parameter_library/package.xml b/generate_parameter_library/package.xml
index fcd45037..a22be029 100644
--- a/generate_parameter_library/package.xml
+++ b/generate_parameter_library/package.xml
@@ -24,6 +24,11 @@
   <depend>rclcpp_lifecycle</depend>
   <depend>rsl</depend>
   <depend>tcb_span</depend>
+  <depend>libexpected-dev</depend>
+
+  <!-- for backward compatibility -->
+  <!-- remove once this redirection is removed -->
+  <!-- https://github.com/PickNikRobotics/cpp_polyfills/pull/12 -->
   <depend>tl_expected</depend>
 
   <export>