Fix standalone setup.cmake version resolution to avoid invalid vX.Y.Z checkout

.github/workflows/ci.yml

@@ -22,6 +22,9 @@ jobs:
       - name: Run provider merging tests
         run: cmake -P tests/install/test_provider_merge.cmake
 
+      - name: Run setup.cmake version resolution test
+        run: cmake -P tests/setup/test_setup_version_resolution.cmake
+
   integration-tests:
     name: Integration Tests
     runs-on: ubuntu-latest
@@ -152,4 +155,3 @@ jobs:
           test -f templates/Doxyfile.in
           test -f templates/custom.css
           echo "✓ All template files present"
-

setup.cmake

@@ -9,22 +9,55 @@
 
 cmake_minimum_required(VERSION 3.20)
 
-# Detect cpp-library version from git tags
+# Extract latest semantic version from a list of refs/tags/vX.Y.Z entries
+function(extract_latest_cpp_library_version_from_tags TAG_REFS OUTPUT_VAR)
+    string(REGEX MATCHALL "refs/tags/v[0-9]+\\.[0-9]+\\.[0-9]+" TAG_REFS_MATCHES "${TAG_REFS}")
+
+    set(SEMVER_TAGS "")
+    foreach(tag_ref IN LISTS TAG_REFS_MATCHES)
+        string(REGEX REPLACE "^refs/tags/v" "" semver "${tag_ref}")
+        list(APPEND SEMVER_TAGS "${semver}")
+    endforeach()
+
+    if(SEMVER_TAGS)
+        list(REMOVE_DUPLICATES SEMVER_TAGS)
+        list(SORT SEMVER_TAGS COMPARE NATURAL ORDER DESCENDING)
+        list(GET SEMVER_TAGS 0 latest_version)
+        set(${OUTPUT_VAR} "${latest_version}" PARENT_SCOPE)
+    else()
+        set(${OUTPUT_VAR} "" PARENT_SCOPE)
+    endif()
+endfunction()
+
+# Detect cpp-library version from local git tags first
+set(CPP_LIBRARY_VERSION "")
 execute_process(
     COMMAND git describe --tags --abbrev=0
     WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
     OUTPUT_VARIABLE CPP_LIBRARY_GIT_VERSION
     OUTPUT_STRIP_TRAILING_WHITESPACE
     ERROR_QUIET
 )
-
-# Clean version (remove 'v' prefix if present)
 if(CPP_LIBRARY_GIT_VERSION)
     string(REGEX REPLACE "^v" "" CPP_LIBRARY_VERSION "${CPP_LIBRARY_GIT_VERSION}")
-else()
-    # Fallback to X.Y.Z placeholder if no git tag found
-    set(CPP_LIBRARY_VERSION "X.Y.Z")
-    message(WARNING "No git tag found for cpp-library version. Using placeholder 'X.Y.Z'. Check https://github.com/stlab/cpp-library/releases for the latest version.")
+endif()
+
+# If setup.cmake is downloaded standalone (no local tags), detect from remote tags
+if(NOT CPP_LIBRARY_VERSION)
+    execute_process(
+        COMMAND git ls-remote --tags --refs https://github.com/stlab/cpp-library.git v[0-9]*
+        OUTPUT_VARIABLE CPP_LIBRARY_REMOTE_TAGS
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        ERROR_QUIET
+        TIMEOUT 10
+    )
+    extract_latest_cpp_library_version_from_tags("${CPP_LIBRARY_REMOTE_TAGS}" CPP_LIBRARY_VERSION)
+endif()
+
+# Last-resort fallback to main branch so initialization still works
+if(NOT CPP_LIBRARY_VERSION)
+    set(CPP_LIBRARY_VERSION "main")
+    message(WARNING "No git tag found for cpp-library version. Falling back to branch 'main'.")
 endif()
 
 message(STATUS "cpp-library version: ${CPP_LIBRARY_VERSION}")

tests/setup/test_setup_version_resolution.cmake

@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: BSL-1.0
+#
+# Integration test for setup.cmake version detection when run standalone
+#
+# Run as: cmake -P tests/setup/test_setup_version_resolution.cmake
+
+cmake_minimum_required(VERSION 3.20)
+
+if(DEFINED ENV{TMPDIR} AND NOT "$ENV{TMPDIR}" STREQUAL "")
+    set(TEST_BASE_DIR "$ENV{TMPDIR}")
+elseif(DEFINED ENV{TEMP} AND NOT "$ENV{TEMP}" STREQUAL "")
+    set(TEST_BASE_DIR "$ENV{TEMP}")
+elseif(DEFINED ENV{TMP} AND NOT "$ENV{TMP}" STREQUAL "")
+    set(TEST_BASE_DIR "$ENV{TMP}")
+else()
+    set(TEST_BASE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+endif()
+
+set(TEST_ROOT_DIR "${TEST_BASE_DIR}/cpp-library-setup-version-test")
+set(TEST_PROJECT_NAME "setup-version-test-lib")
+
+file(REMOVE_RECURSE "${TEST_ROOT_DIR}")
+file(MAKE_DIRECTORY "${TEST_ROOT_DIR}")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/../../setup.cmake" DESTINATION "${TEST_ROOT_DIR}")
+
+execute_process(
+    COMMAND
+        ${CMAKE_COMMAND}
+        -P
+        setup.cmake
+        --
+        --name=${TEST_PROJECT_NAME}
+        --namespace=testns
+        --description=test
+        --header-only=yes
+        --examples=no
+        --tests=no
+    WORKING_DIRECTORY "${TEST_ROOT_DIR}"
+    RESULT_VARIABLE SETUP_RESULT
+    OUTPUT_VARIABLE SETUP_OUTPUT
+    ERROR_VARIABLE SETUP_ERROR
+)
+
+if(NOT SETUP_RESULT EQUAL 0)
+    message(FATAL_ERROR "setup.cmake failed with exit code ${SETUP_RESULT}\nstdout:\n${SETUP_OUTPUT}\nstderr:\n${SETUP_ERROR}")
+endif()
+
+set(GENERATED_CMAKE_LISTS "${TEST_ROOT_DIR}/${TEST_PROJECT_NAME}/CMakeLists.txt")
+if(NOT EXISTS "${GENERATED_CMAKE_LISTS}")
+    message(FATAL_ERROR "Generated CMakeLists.txt not found: ${GENERATED_CMAKE_LISTS}")
+endif()
+
+file(READ "${GENERATED_CMAKE_LISTS}" GENERATED_CONTENT)
+
+if(GENERATED_CONTENT MATCHES "CPMAddPackage\\(\"gh:stlab/cpp-library@X\\.Y\\.Z\"\\)")
+    message(FATAL_ERROR "setup.cmake generated placeholder version X.Y.Z, which should never be emitted.")
+endif()
+
+if(NOT GENERATED_CONTENT MATCHES "CPMAddPackage\\(\"gh:stlab/cpp-library@([0-9]+\\.[0-9]+\\.[0-9]+|main)\"\\)")
+    message(FATAL_ERROR "setup.cmake generated invalid cpp-library version reference in CPMAddPackage.")
+endif()
+
+message(STATUS "✓ setup.cmake generated a valid cpp-library version reference")
+
+file(REMOVE_RECURSE "${TEST_ROOT_DIR}")