From 58d99508421d6a767d8d7c4aa6eb2db54ccba1fa Mon Sep 17 00:00:00 2001
From: Vito Gamberini <vito.gamberini@kitware.com>
Date: Mon, 30 Jun 2025 11:11:06 -0400
Subject: [PATCH] CPS: Fix empty configuration field on noconfig builds

Fixes: #27044
---
 Source/cmExportBuildPackageInfoGenerator.cxx  |  3 ++-
 .../cmExportInstallPackageInfoGenerator.cxx   |  2 +-
 .../ExportPackageInfo/Assertions.cmake        |  5 ++++
 .../PerConfigGeneration-check.cmake           | 14 +++++++++++
 .../PerConfigGeneration.cmake                 | 13 ++++++++++
 .../ExportPackageInfo/RunCMakeTest.cmake      |  1 +
 .../InstallPackageInfo/Assertions.cmake       |  5 ++++
 .../PerConfigGeneration-check.cmake           | 24 +++++++++++++++++++
 .../PerConfigGeneration.cmake                 | 13 ++++++++++
 .../InstallPackageInfo/RunCMakeTest.cmake     |  1 +
 10 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 Tests/RunCMake/ExportPackageInfo/PerConfigGeneration-check.cmake
 create mode 100644 Tests/RunCMake/ExportPackageInfo/PerConfigGeneration.cmake
 create mode 100644 Tests/RunCMake/InstallPackageInfo/PerConfigGeneration-check.cmake
 create mode 100644 Tests/RunCMake/InstallPackageInfo/PerConfigGeneration.cmake

diff --git a/Source/cmExportBuildPackageInfoGenerator.cxx b/Source/cmExportBuildPackageInfoGenerator.cxx
index 775360194d..980bb299f0 100644
--- a/Source/cmExportBuildPackageInfoGenerator.cxx
+++ b/Source/cmExportBuildPackageInfoGenerator.cxx
@@ -103,7 +103,8 @@ void cmExportBuildPackageInfoGenerator::GenerateInterfacePropertiesConfig(
   Json::Value component =
     this->GenerateInterfaceConfigProperties(suffix, properties);
   if (!component.empty()) {
-    configurations[config] = std::move(component);
+    configurations[config.empty() ? std::string{ "noconfig" } : config] =
+      std::move(component);
   }
 }
 
diff --git a/Source/cmExportInstallPackageInfoGenerator.cxx b/Source/cmExportInstallPackageInfoGenerator.cxx
index 1571c50b2a..5a660c4e35 100644
--- a/Source/cmExportInstallPackageInfoGenerator.cxx
+++ b/Source/cmExportInstallPackageInfoGenerator.cxx
@@ -117,7 +117,7 @@ void cmExportInstallPackageInfoGenerator::GenerateImportTargetsConfig(
 {
   Json::Value root;
   root["name"] = this->GetPackageName();
-  root["configuration"] = config;
+  root["configuration"] = (config.empty() ? "noconfig" : config);
 
   Json::Value& components = root["components"];
 
diff --git a/Tests/RunCMake/ExportPackageInfo/Assertions.cmake b/Tests/RunCMake/ExportPackageInfo/Assertions.cmake
index 815761841a..068074da2a 100644
--- a/Tests/RunCMake/ExportPackageInfo/Assertions.cmake
+++ b/Tests/RunCMake/ExportPackageInfo/Assertions.cmake
@@ -20,6 +20,11 @@ function(expect_array content expected_length)
   _expect("length" EQUAL "${actual_length}" "${expected_length}" ${ARGN})
 endfunction()
 
+function(expect_object content)
+  string(JSON actual_type TYPE "${content}" ${ARGN})
+  _expect("type" STREQUAL "${actual_type}" "OBJECT" ${ARGN})
+endfunction()
+
 function(expect_null content)
   string(JSON actual_type TYPE "${content}" ${ARGN})
   _expect("type" STREQUAL "${actual_type}" "NULL" ${ARGN})
diff --git a/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration-check.cmake b/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration-check.cmake
new file mode 100644
index 0000000000..221942fe5a
--- /dev/null
+++ b/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration-check.cmake
@@ -0,0 +1,14 @@
+include(${CMAKE_CURRENT_LIST_DIR}/Assertions.cmake)
+
+set(out_dir "${RunCMake_BINARY_DIR}/PerConfigGeneration-build")
+
+file(READ "${out_dir}/foo.cps" content)
+
+if(RunCMake_GENERATOR_IS_MULTI_CONFIG)
+  foreach(config ${CMAKE_CONFIGURATION_TYPES})
+    expect_object("${content}" "components" "foo" "configurations" ${config})
+  endforeach()
+else()
+  include(${RunCMake_TEST_BINARY_DIR}/build_type.cmake)
+  expect_object("${content}" "components" "foo" "configurations" ${config})
+endif()
diff --git a/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration.cmake b/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration.cmake
new file mode 100644
index 0000000000..ed9b29ae9a
--- /dev/null
+++ b/Tests/RunCMake/ExportPackageInfo/PerConfigGeneration.cmake
@@ -0,0 +1,13 @@
+project(PerConfigGeneration CXX)
+
+set(config ${CMAKE_BUILD_TYPE})
+if(NOT config)
+  set(config noconfig)
+endif()
+
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/build_type.cmake" "set(config \"${config}\")")
+
+add_library(foo foo.cxx)
+
+install(TARGETS foo EXPORT foo)
+export(EXPORT foo PACKAGE_INFO foo)
diff --git a/Tests/RunCMake/ExportPackageInfo/RunCMakeTest.cmake b/Tests/RunCMake/ExportPackageInfo/RunCMakeTest.cmake
index 486d5cee5d..6fee4ac24b 100644
--- a/Tests/RunCMake/ExportPackageInfo/RunCMakeTest.cmake
+++ b/Tests/RunCMake/ExportPackageInfo/RunCMakeTest.cmake
@@ -40,3 +40,4 @@ run_cmake(Requirements)
 run_cmake(TargetTypes)
 run_cmake(DependsMultiple)
 run_cmake(LinkOnly)
+run_cmake(PerConfigGeneration)
diff --git a/Tests/RunCMake/InstallPackageInfo/Assertions.cmake b/Tests/RunCMake/InstallPackageInfo/Assertions.cmake
index 815761841a..068074da2a 100644
--- a/Tests/RunCMake/InstallPackageInfo/Assertions.cmake
+++ b/Tests/RunCMake/InstallPackageInfo/Assertions.cmake
@@ -20,6 +20,11 @@ function(expect_array content expected_length)
   _expect("length" EQUAL "${actual_length}" "${expected_length}" ${ARGN})
 endfunction()
 
+function(expect_object content)
+  string(JSON actual_type TYPE "${content}" ${ARGN})
+  _expect("type" STREQUAL "${actual_type}" "OBJECT" ${ARGN})
+endfunction()
+
 function(expect_null content)
   string(JSON actual_type TYPE "${content}" ${ARGN})
   _expect("type" STREQUAL "${actual_type}" "NULL" ${ARGN})
diff --git a/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration-check.cmake b/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration-check.cmake
new file mode 100644
index 0000000000..5ff99a5f6b
--- /dev/null
+++ b/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration-check.cmake
@@ -0,0 +1,24 @@
+include(${CMAKE_CURRENT_LIST_DIR}/Assertions.cmake)
+
+set(out_dir "${RunCMake_BINARY_DIR}/PerConfigGeneration-build/CMakeFiles/Export/510c5684a4a8a792eadfb55bc9744983")
+
+macro(check_config)
+  string(TOLOWER "${config}" config_lower)
+  if(NOT EXISTS "${out_dir}/foo@${config_lower}.cps")
+    set(RunCMake_TEST_FAILED
+      "Configuration file for '${config}' does not exist")
+    return()
+  endif()
+
+  file(READ "${out_dir}/foo@${config_lower}.cps" content)
+  expect_value("${content}" "${config}" "configuration")
+endmacro()
+
+if(RunCMake_GENERATOR_IS_MULTI_CONFIG)
+  foreach(config ${CMAKE_CONFIGURATION_TYPES})
+    check_config()
+  endforeach()
+else()
+  include(${RunCMake_TEST_BINARY_DIR}/build_type.cmake)
+  check_config()
+endif()
diff --git a/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration.cmake b/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration.cmake
new file mode 100644
index 0000000000..4f4c149c0d
--- /dev/null
+++ b/Tests/RunCMake/InstallPackageInfo/PerConfigGeneration.cmake
@@ -0,0 +1,13 @@
+project(PerConfigGeneration CXX)
+
+set(config ${CMAKE_BUILD_TYPE})
+if(NOT config)
+  set(config noconfig)
+endif()
+
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/build_type.cmake" "set(config \"${config}\")")
+
+add_library(foo foo.cxx)
+
+install(TARGETS foo EXPORT foo)
+install(PACKAGE_INFO foo DESTINATION cps EXPORT foo)
diff --git a/Tests/RunCMake/InstallPackageInfo/RunCMakeTest.cmake b/Tests/RunCMake/InstallPackageInfo/RunCMakeTest.cmake
index c31a289f55..bcd2ef81a5 100644
--- a/Tests/RunCMake/InstallPackageInfo/RunCMakeTest.cmake
+++ b/Tests/RunCMake/InstallPackageInfo/RunCMakeTest.cmake
@@ -48,4 +48,5 @@ run_cmake(Requirements)
 run_cmake(TargetTypes)
 run_cmake(DependsMultiple)
 run_cmake(DependsMultipleNotInstalled)
+run_cmake(PerConfigGeneration)
 run_cmake_install(Destination)