rapids-cmake: Add support for a version suffix to mean using main (#864)

To support the new RAPIDS wide branching model rapids-cmake has to support switching between the `main` branch for `rapids_cpm_rmm` and a release branch like `branch-25.06`. 

This is implemented by reading the rapids-cmake `VERSION` file and when we detect a value that ends in `a` we know we are being used from the `main` branch (a development version) and not from a release branch.

Fixes #863

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)
  - Bradley Dice (https://github.com/bdice)

URL: #864

Author: robertmaynard

docs/cpm.rst

@@ -156,6 +156,7 @@ as needed.
     installed copy of the project can't be found.
 
     Supports the following placeholders:
+        - ``${rapids-cmake-checkout-tag}`` will be evaluated to ``main`` when using rapids-cmake ``main`` branch, or ``branch-<major>.<minor>`` when not on the 'main' branch, using the rapids-cmake CalVer values.
         - ``${rapids-cmake-version}`` will be evaluated to 'major.minor' of the current rapids-cmake cal-ver value.
         - ``${version}`` will be evaluated to the contents of the ``version`` field.
         - ``$ENV{variable}`` will be evaluated to the contents of the listed environment variable

rapids-cmake/cpm/detail/get_proprietary_binary_url.cmake

@@ -1,5 +1,5 @@
 #=============================================================================
-# Copyright (c) 2023-2024, NVIDIA CORPORATION.
+# Copyright (c) 2023-2025, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -56,12 +56,9 @@ function(rapids_cpm_get_proprietary_binary_url package_name version url_var)
     return()
   endif()
 
-  if(NOT DEFINED rapids-cmake-version)
-    include("${rapids-cmake-dir}/rapids-version.cmake")
-  endif()
-
   # Determine the CUDA Toolkit version so that we properly evaluate the placeholders in
   # `proprietary_binary`
+  include("${rapids-cmake-dir}/rapids-version.cmake")
   if(proprietary_binary MATCHES "{cuda-toolkit-version")
     find_package(CUDAToolkit REQUIRED)
     set(cuda-toolkit-version ${CUDAToolkit_VERSION_MAJOR}.${CUDAToolkit_VERSION_MINOR})

rapids-cmake/cpm/detail/package_details.cmake

@@ -110,10 +110,8 @@ function(rapids_cpm_package_details package_name version_var url_var tag_var sha
   rapids_cpm_json_get_value(always_download)
 
   # Evaluate any magic placeholders in the version or tag components including the
-  # `rapids-cmake-version` value
-  if(NOT DEFINED rapids-cmake-version)
-    include("${rapids-cmake-dir}/rapids-version.cmake")
-  endif()
+  # `rapids-cmake-version` and `rapids-cmake-checkout-tag` values
+  include("${rapids-cmake-dir}/rapids-version.cmake")
 
   cmake_language(EVAL CODE "set(version ${version})")
   cmake_language(EVAL CODE "set(git_tag ${git_tag})")

rapids-cmake/cpm/versions.json

@@ -72,7 +72,7 @@
     "rmm": {
       "version": "${rapids-cmake-version}",
       "git_url": "https://github.com/rapidsai/rmm.git",
-      "git_tag": "branch-${version}"
+      "git_tag": "${rapids-cmake-checkout-tag}"
     },
     "spdlog": {
       "version": "1.14.1",

rapids-cmake/rapids-version.cmake

@@ -16,18 +16,27 @@
 # can't have an include guard on this file
 # that breaks its usage by cpm/detail/package_details
 
-if(NOT DEFINED rapids-cmake-version)
+if(NOT DEFINED rapids-cmake-checkout-tag)
   file(READ "${CMAKE_CURRENT_LIST_DIR}/../VERSION" _rapids_version)
-  if(_rapids_version MATCHES [[^([0-9][0-9])\.([0-9][0-9])\.([0-9][0-9])]])
+  if(_rapids_version MATCHES [[^([0-9][0-9])\.([0-9][0-9])\.([0-9][0-9])(a?)]])
     set(RAPIDS_VERSION_MAJOR "${CMAKE_MATCH_1}")
     set(RAPIDS_VERSION_MINOR "${CMAKE_MATCH_2}")
     set(RAPIDS_VERSION_PATCH "${CMAKE_MATCH_3}")
+    set(RAPIDS_USE_MAIN "${CMAKE_MATCH_4}")
     set(RAPIDS_VERSION_MAJOR_MINOR "${RAPIDS_VERSION_MAJOR}.${RAPIDS_VERSION_MINOR}")
     set(RAPIDS_VERSION "${RAPIDS_VERSION_MAJOR}.${RAPIDS_VERSION_MINOR}.${RAPIDS_VERSION_PATCH}")
   else()
     string(REPLACE "\n" "\n  " _rapids_version_formatted "  ${_rapids_version}")
     message(FATAL_ERROR "Could not determine RAPIDS version. Contents of VERSION file:\n${_rapids_version_formatted}"
     )
   endif()
-  set(rapids-cmake-version ${RAPIDS_VERSION_MAJOR_MINOR})
+
+  if(NOT DEFINED rapids-cmake-version)
+    set(rapids-cmake-version ${RAPIDS_VERSION_MAJOR_MINOR})
+  endif()
+
+  set(rapids-cmake-checkout-tag "branch-${RAPIDS_VERSION_MAJOR_MINOR}")
+  if(RAPIDS_USE_MAIN)
+    set(rapids-cmake-checkout-tag "main")
+  endif()
 endif()

testing/cpm/cpm_init-override-multiple.cmake

@@ -42,7 +42,7 @@ file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/default.json
     "rmm": {
       "version": "${rapids-cmake-version}",
       "git_url": "https://github.com/rapidsai/rmm.git",
-      "git_tag": "branch-${version}"
+      "git_tag": "${rapids-cmake-checkout-tag}"
     },
     "GTest": {
       "version": "1.16.0",

testing/cpm/cpm_package_override-defaults-with-different-casing.cmake

@@ -25,7 +25,7 @@ file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/default.json
     "rmm": {
       "version": "${rapids-cmake-version}",
       "git_url": "https://github.com/rapidsai/rmm.git",
-      "git_tag": "branch-${version}"
+      "git_tag": "${rapids-cmake-checkout-tag}"
     },
     "GTest": {
       "version": "1.16.0",

testing/cpm/cpm_package_override-simple.cmake

@@ -24,7 +24,7 @@ file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/default.json
     "rmm": {
       "version": "${rapids-cmake-version}",
       "git_url": "https://github.com/rapidsai/rmm.git",
-      "git_tag": "branch-${version}"
+      "git_tag": "${rapids-cmake-checkout-tag}"
     },
     "GTest": {
       "version": "1.16.0",

testing/other/rapids_cmake-multiple-cpm/A/CMakeLists.txt

@@ -1,5 +1,5 @@
 #=============================================================================
-# Copyright (c) 2021, NVIDIA CORPORATION.
+# Copyright (c) 2021-2025, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -37,5 +37,9 @@ if(NOT DEFINED rapids-cmake-version)
   message(FATAL_ERROR "expected variable rapids-cmake-version to exist")
 endif()
 
+if(NOT DEFINED rapids-cmake-checkout-tag)
+  message(FATAL_ERROR "expected variable rapids-cmake-checkout-tag to exist")
+endif()
+
 # Be hostile against rapids-cmake
 set(CMAKE_MODULE_PATH "/not/a/directory")

testing/other/rapids_cmake-multiple-cpm/B/CMakeLists.txt

@@ -1,5 +1,5 @@
 #=============================================================================
-# Copyright (c) 2021, NVIDIA CORPORATION.
+# Copyright (c) 2021-2025, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -36,3 +36,7 @@ endif()
 if(NOT DEFINED rapids-cmake-version)
   message(FATAL_ERROR "expected variable rapids-cmake-version to exist")
 endif()
+
+if(NOT DEFINED rapids-cmake-checkout-tag)
+  message(FATAL_ERROR "expected variable rapids-cmake-checkout-tag to exist")
+endif()