Allow system name reinit

CMCONF.cmake

@@ -111,6 +111,11 @@ INCLUDE_GUARD(GLOBAL)
 
 FIND_PACKAGE(CMLIB REQUIRED)
 
+SET(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED OFF
+    CACHE BOOL
+    "If set to ON the system name can be overriden from cmdline. If OFF the system name cannot be changed once set."
+)
+
 SET(CMCONF_SYSTEM_NAME ""
     CACHE STRING
     "Name of the system for which the configuration is intended."
@@ -168,24 +173,27 @@ SET(CMCONF_INSTALL_CMAKELISTS_TEMPLATE_FILE "${CMCONF_SCRIPT_DIR}/resource/CMake
 #
 # Sets the system name that will be used to group configuration variables
 # and identify the configuration package in the CMake user package registry.
-# The system name can only be set once per configuration session.
 #
 # If CMCONF_INSTALL_AS_SYMLINK is ON, this function will automatically install
 # the configuration to the CMake user package registry as a symlink, making it
 # available for other projects to find via FIND_PACKAGE.
 #
 # The system name is normalized to uppercase and validated to contain only
-# [a-zA-Z_] characters. Once set, attempting to change it will result in
-# a fatal error.
+# [a-zA-Z_] characters.
+#
+# System Name Override Behavior:
+# - By default (CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=OFF), attempting to change
+#   the system name after it has been set will result in a fatal error.
+# - If CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is set to ON, the system name can be
+#   changed. A warning message is emitted when the system name is overridden.
+# - Re-initializing with the same system name is allowed and proceeds silently.
 #
 # Installation Process (when CMCONF_INSTALL_AS_SYMLINK=ON):
 # - Validates that no conflicting package exists in a different location
 # - In script mode: validates filename matches CMCONF_<SYSTEM_NAME>Config.cmake pattern
 # - Registers the package using EXPORT(PACKAGE) command
 # - Installation is performed only once per session
 #
-# System name cannot be changed once is set.
-#
 # <function>(
 #		<system_name>		# Name of the system. Will be converted to uppercase,
 #							# must contain only [a-zA-Z_] characters.
@@ -195,7 +203,11 @@ FUNCTION(CMCONF_INIT_SYSTEM system_name)
     _CMCONF_CHECK_AND_NORMALIZE_SYSTEM_NAME("${system_name}" system_name_upper)
     IF(CMCONF_SYSTEM_NAME)
         IF(NOT CMCONF_SYSTEM_NAME STREQUAL "${system_name_upper}")
-            _CMCONF_MESSAGE(FATAL_ERROR "System name already set. Cannot change system name from '${CMCONF_SYSTEM_NAME}' to '${system_name_upper}'")
+            IF(NOT CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED)
+                _CMCONF_MESSAGE(FATAL_ERROR "System name already set. Cannot change system name from '${CMCONF_SYSTEM_NAME}' to '${system_name_upper}'")
+            ELSE()
+                _CMCONF_MESSAGE(WARNING "Overriding system name from '${CMCONF_SYSTEM_NAME}' to '${system_name_upper}'")
+            ENDIF()
         ENDIF()
     ENDIF()
     SET_PROPERTY(CACHE CMCONF_SYSTEM_NAME PROPERTY VALUE "${system_name_upper}")
@@ -416,6 +428,10 @@ FUNCTION(_CMCONF_UNINSTALL system_name)
         _CMCONF_MESSAGE(FATAL_ERROR "Cannot uninstall configuration. Uninstalation can be invoked only as 'cmake -DCMCONF_UNINSTALL=ON -P <CONFIG_FILE>.'")
     ENDIF()
 
+    IF(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED)
+        _CMCONF_MESSAGE(FATAL_ERROR "Cannot uninstall configuration. CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is not allowed during CMCONF config uninstallation.")
+    ENDIF()
+
     SET(package_registry_path)
     IF(WIN32)
         SET(winreg_path "HKCU\\Software\\Kitware\\CMake\\Packages\\${package_name}")
@@ -490,7 +506,7 @@ FUNCTION(_CMCONF_RUN_INSTALL_PROJECT system_name)
     CONFIGURE_FILE("${cmakelist_template}" "${cmakelist_path}" @ONLY)
 
     EXECUTE_PROCESS(
-        COMMAND "${CMAKE_COMMAND}" -DCMCONF_INSTALL_AS_SYMLINK=ON .
+        COMMAND "${CMAKE_COMMAND}" -DCMCONF_INSTALL_AS_SYMLINK=ON -DCMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=${CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED} .
         WORKING_DIRECTORY "${script_dir}"
         RESULT_VARIABLE result_var
         ERROR_VARIABLE errout

README.md

@@ -81,6 +81,26 @@ CMCONF_GET("PAHOMQTT_URI")
 
 Examples can be found at [example] directory.
 
+## Configuration Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `CMCONF_INSTALL_AS_SYMLINK` | OFF | Triggers configuration installation to CMake user package registry |
+| `CMCONF_UNINSTALL` | OFF | Triggers configuration uninstallation from CMake user package registry |
+| `CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED` | OFF | When set during a normal CMake project configure, allows changing `CMCONF_SYSTEM_NAME` after it has been set (emits warning). When used during installation via config script (e.g., running with `-P` or with `CMCONF_INSTALL_AS_SYMLINK`/`CMCONF_UNINSTALL`), a configuration error occurs. |
+| `CMCONF_SYSTEM_NAME` | "" | Name of the system (usually set via `CMCONF_INIT_SYSTEM`, but can be preset if `CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED` is ON) |
+
+```bash
+# Install configuration
+cmake -DCMCONF_INSTALL_AS_SYMLINK=ON -P CMCONF_EXAMPLEConfig.cmake
+
+# Uninstall configuration
+cmake -DCMCONF_UNINSTALL=ON -P CMCONF_EXAMPLEConfig.cmake
+
+# Allow system name override (e.g., in CMake project root directory)
+cmake -DCMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON -DCMCONF_SYSTEM_NAME=MY_EXAMPLE .
+```
+
 ## Function list
 
 Each entry in list represents one feature for CMake.

resource/CMakeLists.txt.in

@@ -9,6 +9,10 @@ SET(CMCONF_CMAKE_PROJECT_ALLOW_INSTALL ON
     "Set by resource/CMakeLists.txt.in. Do not set manually. Controls whetnever CMake project is allowed to install the configuration."
 )
 
+IF(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED)
+    MESSAGE(FATAL_ERROR "CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is not allowed during CMCONF config installation.")
+ENDIF()
+
 _CMCONF_GET_PACKAGE_CONFIG_FILENAME("@TO_REPLACE_CMCONF_SYSTEM_NAME@" package_filename)
 
 FILE(TO_CMAKE_PATH "${CMAKE_CURRENT_LIST_DIR}/${package_filename}" package_path)

test/CMakeLists.txt

@@ -21,6 +21,8 @@ TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/different_system_names")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/env_variable_fallback")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/env_variable_override")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/multiple_variables")
+TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/system_name_override_allowed")
+TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/system_name_reinit_same")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/pass/uninstall_verification")
 
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/config_not_installed")
@@ -29,6 +31,7 @@ TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/env_variable_config_required
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/get_after_set")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/install_from_cmake_project")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/install_project_execution_failure")
+TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/install_with_override_allowed")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/invalid_system_name")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/invalid_variable_name")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/package_exists_different_location")
@@ -38,6 +41,7 @@ TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/system_not_set")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/uninstall_from_cmake_project")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/uninstall_install_conflict")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/uninstall_not_needed_warning")
+TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/uninstall_with_override_allowed")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/variable_already_exists")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/variable_not_defined")
 TEST_RUN("${CMAKE_CURRENT_LIST_DIR}/test_cases/fail/wrong_filename")

test/test_cases/fail/install_with_override_allowed/CMakeLists.txt

@@ -0,0 +1,29 @@
+## Main
+#
+# Test CMCONF installation error when CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is ON
+#
+
+IF(NOT DEFINED CMAKE_SCRIPT_MODE_FILE)
+    CMAKE_MINIMUM_REQUIRED(VERSION 3.22)
+    PROJECT(CMCONF_INSTALL_WITH_OVERRIDE_ALLOWED_TEST)
+ENDIF()
+
+FIND_PACKAGE(CMLIB REQUIRED)
+
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../TEST.cmake")
+
+EXECUTE_PROCESS(
+    COMMAND "${CMAKE_COMMAND}" -DCMCONF_INSTALL_AS_SYMLINK=ON -DCMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON -P "${CMAKE_CURRENT_LIST_DIR}/../../../config_templates/CMCONF_TEST_SYSTEMConfig.cmake"
+    RESULT_VARIABLE install_result
+    ERROR_VARIABLE install_error
+    OUTPUT_VARIABLE install_output
+)
+
+IF(install_result EQUAL 0)
+    MESSAGE(FATAL_ERROR "Expected installation to fail when CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON but it succeeded")
+ENDIF()
+
+IF(NOT install_error MATCHES "CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is not allowed during CMCONF config.*installation")
+    MESSAGE(FATAL_ERROR "Expected error message not found in output: ${install_error}")
+ENDIF()
+

test/test_cases/fail/uninstall_with_override_allowed/CMakeLists.txt

@@ -0,0 +1,29 @@
+## Main
+#
+# Test CMCONF uninstallation error when CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is ON
+#
+
+IF(NOT DEFINED CMAKE_SCRIPT_MODE_FILE)
+    CMAKE_MINIMUM_REQUIRED(VERSION 3.22)
+    PROJECT(CMCONF_UNINSTALL_WITH_OVERRIDE_ALLOWED_TEST)
+ENDIF()
+
+FIND_PACKAGE(CMLIB REQUIRED)
+
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../TEST.cmake")
+
+EXECUTE_PROCESS(
+    COMMAND "${CMAKE_COMMAND}" -DCMCONF_UNINSTALL=ON -DCMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON -P "${CMAKE_CURRENT_LIST_DIR}/../../../config_templates/CMCONF_TEST_SYSTEMConfig.cmake"
+    RESULT_VARIABLE uninstall_result
+    ERROR_VARIABLE uninstall_error
+    OUTPUT_VARIABLE uninstall_output
+)
+
+IF(uninstall_result EQUAL 0)
+    MESSAGE(FATAL_ERROR "Expected uninstallation to fail when CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON but it succeeded")
+ENDIF()
+
+IF(NOT uninstall_error MATCHES "CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED is not allowed during CMCONF config.*uninstallation")
+    MESSAGE(FATAL_ERROR "Expected error message not found in output: ${uninstall_error}")
+ENDIF()
+

test/test_cases/pass/system_name_override_allowed/CMakeLists.txt

@@ -0,0 +1,18 @@
+## Main
+#
+# Test CMCONF_INIT_SYSTEM allows changing system name when CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED=ON
+#
+
+IF(NOT DEFINED CMAKE_SCRIPT_MODE_FILE)
+    CMAKE_MINIMUM_REQUIRED(VERSION 3.22)
+    PROJECT(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED_TEST)
+ENDIF()
+
+FIND_PACKAGE(CMLIB REQUIRED)
+
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../TEST.cmake")
+
+TEST_RUN_AND_CHECK_OUTPUT("test_config"
+    WARNING_MESSAGE "CMCONF\\\\[FIRST_SYSTEM\\\\] - Overriding system name from 'FIRST_SYSTEM' to.*'SECOND_SYSTEM'"
+)
+

test/test_cases/pass/system_name_override_allowed/test_config/CMakeLists.txt

@@ -0,0 +1,19 @@
+IF(NOT DEFINED CMAKE_SCRIPT_MODE_FILE)
+    CMAKE_MINIMUM_REQUIRED(VERSION 3.22)
+    PROJECT(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED_TEST_CONFIG)
+ENDIF()
+
+FIND_PACKAGE(CMLIB REQUIRED)
+
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../../../CMCONF.cmake")
+
+SET(CMCONF_SYSTEM_NAME_OVERRIDE_ALLOWED ON CACHE INTERNAL "" FORCE)
+
+CMCONF_INIT_SYSTEM("FIRST_SYSTEM")
+
+CMCONF_INIT_SYSTEM("SECOND_SYSTEM")
+
+IF(NOT CMCONF_SYSTEM_NAME STREQUAL "SECOND_SYSTEM")
+    MESSAGE(FATAL_ERROR "System name should be SECOND_SYSTEM but is '${CMCONF_SYSTEM_NAME}'")
+ENDIF()
+

test/test_cases/pass/system_name_reinit_same/CMakeLists.txt

@@ -0,0 +1,24 @@
+## Main
+#
+# Test CMCONF_INIT_SYSTEM allows re-initialization with the same system name silently
+#
+
+IF(NOT DEFINED CMAKE_SCRIPT_MODE_FILE)
+    CMAKE_MINIMUM_REQUIRED(VERSION 3.22)
+    PROJECT(CMCONF_SYSTEM_NAME_REINIT_SAME_TEST)
+ENDIF()
+
+FIND_PACKAGE(CMLIB REQUIRED)
+
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../TEST.cmake")
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../cache_var.cmake")
+INCLUDE("${CMAKE_CURRENT_LIST_DIR}/../../../../CMCONF.cmake")
+
+CMCONF_INIT_SYSTEM("TEST_REINIT")
+CMCONF_INIT_SYSTEM("TEST_REINIT")
+CMCONF_INIT_SYSTEM("test_reinit")
+
+IF(NOT CMCONF_SYSTEM_NAME STREQUAL "TEST_REINIT")
+    MESSAGE(FATAL_ERROR "System name should be TEST_REINIT but is '${CMCONF_SYSTEM_NAME}'")
+ENDIF()
+