Merge topic 'fc-ep-git-update-strategy'

8aa4d51ec5 ExternalProject: Add missing release note for git update strategy
1236590507 FetchContent: Pass through CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY if set
e71c2807ba ExternalProject: Remote checkout needs to include the remote name

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4818

2 files changed, 75 insertions, 59 deletions

diff --git a/Modules/ExternalProject-gitupdate.cmake.in b/Modules/ExternalProject-gitupdate.cmake.in
index e993c3c..eff39c1 100644
--- a/Modules/ExternalProject-gitupdate.cmake.in
+++ b/Modules/ExternalProject-gitupdate.cmake.in
@@ -59,7 +59,7 @@ if(error_code OR is_remote_ref OR NOT ("${tag_sha}" STREQUAL "${head_sha}"))
     message(FATAL_ERROR "Failed to fetch repository '@git_repository@'")
   endif()
 
-  if(is_remote_ref AND NOT "@git_update_strategy@" STREQUAL "CHECKOUT")
+  if(is_remote_ref)
     # Check if stash is needed
     execute_process(
       COMMAND "@git_EXECUTABLE@" status --porcelain
@@ -72,8 +72,8 @@ if(error_code OR is_remote_ref OR NOT ("${tag_sha}" STREQUAL "${head_sha}"))
     endif()
     string(LENGTH "${repo_status}" need_stash)
 
-    # If not in clean state, stash changes in order to be able to be able to
-    # perform git pull --rebase
+    # If not in clean state, stash changes in order to be able to perform a
+    # rebase or checkout without losing those changes permanently
     if(need_stash)
       execute_process(
         COMMAND "@git_EXECUTABLE@" stash save @git_stash_save_options@
@@ -85,66 +85,77 @@ if(error_code OR is_remote_ref OR NOT ("${tag_sha}" STREQUAL "${head_sha}"))
       endif()
     endif()
 
-    # Pull changes from the remote branch
-    execute_process(
-      COMMAND "@git_EXECUTABLE@" rebase "${git_remote}/${git_tag}"
-      WORKING_DIRECTORY "@work_dir@"
-      RESULT_VARIABLE error_code
-      OUTPUT_VARIABLE rebase_output
-      ERROR_VARIABLE  rebase_output
-      )
-    if(error_code)
-      # Rebase failed, undo the rebase attempt before continuing
+    if("@git_update_strategy@" STREQUAL "CHECKOUT")
       execute_process(
-        COMMAND "@git_EXECUTABLE@" rebase --abort
-        WORKING_DIRECTORY "@work_dir@"
-      )
-
-      if(NOT "@git_update_strategy@" STREQUAL "REBASE_CHECKOUT")
-        # Not allowed to do a checkout as a fallback, so cannot proceed
-        if(need_stash)
-          execute_process(
-            COMMAND "@git_EXECUTABLE@" stash pop --index --quiet
-            WORKING_DIRECTORY "@work_dir@"
-            )
-        endif()
-        message(FATAL_ERROR "\nFailed to rebase in: '@work_dir@'."
-                            "\nOutput from the attempted rebase follows:"
-                            "\n${rebase_output}"
-                            "\n\nYou will have to resolve the conflicts manually")
-      endif()
-
-      # Fall back to checkout. We create an annotated tag so that the user
-      # can manually inspect the situation and revert if required.
-      # We can't log the failed rebase output because MSVC sees it and
-      # intervenes, causing the build to fail even though it completes.
-      # Write it to a file instead.
-      string(TIMESTAMP tag_timestamp "%Y%m%dT%H%M%S" UTC)
-      set(tag_name _cmake_ExternalProject_moved_from_here_${tag_timestamp}Z)
-      set(error_log_file ${CMAKE_CURRENT_LIST_DIR}/rebase_error_${tag_timestamp}Z.log)
-      file(WRITE ${error_log_file} "${rebase_output}")
-      message(WARNING "Rebase failed, output has been saved to ${error_log_file}"
-                      "\nFalling back to checkout, previous commit tagged as ${tag_name}")
-      execute_process(
-        COMMAND "@git_EXECUTABLE@" tag -a
-                -m "ExternalProject attempting to move from here to ${git_remote}/${git_tag}"
-                ${tag_name}
+        COMMAND "@git_EXECUTABLE@" checkout "${git_remote}/${git_tag}"
         WORKING_DIRECTORY "@work_dir@"
         RESULT_VARIABLE error_code
-      )
+        )
       if(error_code)
-        message(FATAL_ERROR "Failed to add marker tag")
+        message(FATAL_ERROR "Failed to checkout tag: '${git_remote}/${git_tag}'")
       endif()
-
+    else()
+      # Pull changes from the remote branch
       execute_process(
-        COMMAND "@git_EXECUTABLE@" checkout ${git_remote}/${git_tag}
+        COMMAND "@git_EXECUTABLE@" rebase "${git_remote}/${git_tag}"
         WORKING_DIRECTORY "@work_dir@"
         RESULT_VARIABLE error_code
-      )
+        OUTPUT_VARIABLE rebase_output
+        ERROR_VARIABLE  rebase_output
+        )
       if(error_code)
-        message(FATAL_ERROR "Failed to checkout : '${git_remote}/${git_tag}'")
-      endif()
+        # Rebase failed, undo the rebase attempt before continuing
+        execute_process(
+          COMMAND "@git_EXECUTABLE@" rebase --abort
+          WORKING_DIRECTORY "@work_dir@"
+        )
+
+        if(NOT "@git_update_strategy@" STREQUAL "REBASE_CHECKOUT")
+          # Not allowed to do a checkout as a fallback, so cannot proceed
+          if(need_stash)
+            execute_process(
+              COMMAND "@git_EXECUTABLE@" stash pop --index --quiet
+              WORKING_DIRECTORY "@work_dir@"
+              )
+          endif()
+          message(FATAL_ERROR "\nFailed to rebase in: '@work_dir@'."
+                              "\nOutput from the attempted rebase follows:"
+                              "\n${rebase_output}"
+                              "\n\nYou will have to resolve the conflicts manually")
+        endif()
+
+        # Fall back to checkout. We create an annotated tag so that the user
+        # can manually inspect the situation and revert if required.
+        # We can't log the failed rebase output because MSVC sees it and
+        # intervenes, causing the build to fail even though it completes.
+        # Write it to a file instead.
+        string(TIMESTAMP tag_timestamp "%Y%m%dT%H%M%S" UTC)
+        set(tag_name _cmake_ExternalProject_moved_from_here_${tag_timestamp}Z)
+        set(error_log_file ${CMAKE_CURRENT_LIST_DIR}/rebase_error_${tag_timestamp}Z.log)
+        file(WRITE ${error_log_file} "${rebase_output}")
+        message(WARNING "Rebase failed, output has been saved to ${error_log_file}"
+                        "\nFalling back to checkout, previous commit tagged as ${tag_name}")
+        execute_process(
+          COMMAND "@git_EXECUTABLE@" tag -a
+                  -m "ExternalProject attempting to move from here to ${git_remote}/${git_tag}"
+                  ${tag_name}
+          WORKING_DIRECTORY "@work_dir@"
+          RESULT_VARIABLE error_code
+        )
+        if(error_code)
+          message(FATAL_ERROR "Failed to add marker tag")
+        endif()
+
+        execute_process(
+          COMMAND "@git_EXECUTABLE@" checkout "${git_remote}/${git_tag}"
+          WORKING_DIRECTORY "@work_dir@"
+          RESULT_VARIABLE error_code
+        )
+        if(error_code)
+          message(FATAL_ERROR "Failed to checkout : '${git_remote}/${git_tag}'")
+        endif()
 
+      endif()
     endif()
 
     if(need_stash)
diff --git a/Modules/FetchContent.cmake b/Modules/FetchContent.cmake
index 69f2513..e05ca96 100644
--- a/Modules/FetchContent.cmake
+++ b/Modules/FetchContent.cmake
@@ -930,16 +930,16 @@ ExternalProject_Add_Step(${contentName}-populate copyfile
   endif()
 
   if(CMAKE_GENERATOR)
-    set(generatorOpts "-G${CMAKE_GENERATOR}")
+    set(subCMakeOpts "-G${CMAKE_GENERATOR}")
     if(CMAKE_GENERATOR_PLATFORM)
-      list(APPEND generatorOpts "-A${CMAKE_GENERATOR_PLATFORM}")
+      list(APPEND subCMakeOpts "-A${CMAKE_GENERATOR_PLATFORM}")
     endif()
     if(CMAKE_GENERATOR_TOOLSET)
-      list(APPEND generatorOpts "-T${CMAKE_GENERATOR_TOOLSET}")
+      list(APPEND subCMakeOpts "-T${CMAKE_GENERATOR_TOOLSET}")
     endif()
 
     if(CMAKE_MAKE_PROGRAM)
-      list(APPEND generatorOpts "-DCMAKE_MAKE_PROGRAM:FILEPATH=${CMAKE_MAKE_PROGRAM}")
+      list(APPEND subCMakeOpts "-DCMAKE_MAKE_PROGRAM:FILEPATH=${CMAKE_MAKE_PROGRAM}")
     endif()
 
   else()
@@ -947,7 +947,12 @@ ExternalProject_Add_Step(${contentName}-populate copyfile
     # generator is set (and hence CMAKE_MAKE_PROGRAM could not be
     # trusted even if provided). We will have to rely on being
     # able to find the default generator and build tool.
-    unset(generatorOpts)
+    unset(subCMakeOpts)
+  endif()
+
+  if(DEFINED CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY)
+    list(APPEND subCMakeOpts
+      "-DCMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY=${CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY}")
   endif()
 
   # Create and build a separate CMake project to carry out the population.
@@ -958,7 +963,7 @@ ExternalProject_Add_Step(${contentName}-populate copyfile
   configure_file("${CMAKE_CURRENT_FUNCTION_LIST_DIR}/FetchContent/CMakeLists.cmake.in"
                  "${ARG_SUBBUILD_DIR}/CMakeLists.txt")
   execute_process(
-    COMMAND ${CMAKE_COMMAND} ${generatorOpts} .
+    COMMAND ${CMAKE_COMMAND} ${subCMakeOpts} .
     RESULT_VARIABLE result
     ${outputOptions}
     WORKING_DIRECTORY "${ARG_SUBBUILD_DIR}"