From 819015ef3a6f13ede0992821ba8cd15696f83655 Mon Sep 17 00:00:00 2001
From: Gereon Kremer <gereon.kremer@cs.rwth-aachen.de>
Date: Thu, 9 Jan 2014 15:07:10 +0100
Subject: [PATCH] ExternalProject: Add option GIT_SUBMODULES

This option allows to filter the submodules that are checked out.
Add a simple testcase for GIT_SUBMODULES option passing an empty list.
---
 Modules/ExternalProject.cmake        | 15 +++++++++------
 Tests/ExternalProject/CMakeLists.txt | 16 ++++++++++++++++
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index 1c1bd2fa1..0df51a878 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -30,6 +30,7 @@
 #    [SVN_TRUST_CERT 1 ]         # Trust the Subversion server site certificate
 #    [GIT_REPOSITORY url]        # URL of git repo
 #    [GIT_TAG tag]               # Git branch name, commit id or tag
+#    [GIT_SUBMODULES modules...] # Git submodules that shall be updated, all if empty
 #    [HG_REPOSITORY url]         # URL of mercurial repo
 #    [HG_TAG tag]                # Mercurial branch name, commit id or tag
 #    [URL /.../src.tgz]          # Full path or URL of source
@@ -289,7 +290,7 @@ define_property(DIRECTORY PROPERTY "EP_STEP_TARGETS" INHERITED
   )
 
 
-function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git_repository git_tag src_name work_dir gitclone_infofile gitclone_stampfile)
+function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git_repository git_tag git_submodules src_name work_dir gitclone_infofile gitclone_stampfile)
   file(WRITE ${script_filename}
 "if(\"${git_tag}\" STREQUAL \"\")
   message(FATAL_ERROR \"Tag for git checkout should not be empty.\")
@@ -352,7 +353,7 @@ if(error_code)
 endif()
 
 execute_process(
-  COMMAND \"${git_EXECUTABLE}\" submodule update --recursive
+  COMMAND \"${git_EXECUTABLE}\" submodule update --recursive ${git_submodules}
   WORKING_DIRECTORY \"${work_dir}/${src_name}\"
   RESULT_VARIABLE error_code
   )
@@ -440,7 +441,7 @@ endif()
 endfunction()
 
 
-function(_ep_write_gitupdate_script script_filename git_EXECUTABLE git_tag git_repository work_dir)
+function(_ep_write_gitupdate_script script_filename git_EXECUTABLE git_tag git_submodules git_repository work_dir)
   file(WRITE ${script_filename}
 "if(\"${git_tag}\" STREQUAL \"\")
   message(FATAL_ERROR \"Tag for git checkout should not be empty.\")
@@ -499,7 +500,7 @@ if(error_code OR is_remote_ref OR NOT (\"\${tag_sha}\" STREQUAL \"\${head_sha}\"
   endif()
 
   execute_process(
-    COMMAND \"${git_EXECUTABLE}\" submodule update --recursive
+    COMMAND \"${git_EXECUTABLE}\" submodule update --recursive ${git_submodules}
     WORKING_DIRECTORY \"${work_dir}/${src_name}\"
     RESULT_VARIABLE error_code
     )
@@ -1323,6 +1324,7 @@ function(_ep_add_download_command name)
     if(NOT git_tag)
       set(git_tag "master")
     endif()
+    get_property(git_submodules TARGET ${name} PROPERTY _EP_GIT_SUBMODULES)
 
     # For the download step, and the git clone operation, only the repository
     # should be recorded in a configured RepositoryInfo file. If the repo
@@ -1347,7 +1349,7 @@ function(_ep_add_download_command name)
     # The script will delete the source directory and then call git clone.
     #
     _ep_write_gitclone_script(${tmp_dir}/${name}-gitclone.cmake ${source_dir}
-      ${GIT_EXECUTABLE} ${git_repository} ${git_tag} ${src_name} ${work_dir}
+      ${GIT_EXECUTABLE} ${git_repository} ${git_tag} "${git_submodules}" ${src_name} ${work_dir}
       ${stamp_dir}/${name}-gitinfo.txt ${stamp_dir}/${name}-gitclone-lastrun.txt
       )
     set(comment "Performing download step (git clone) for '${name}'")
@@ -1541,8 +1543,9 @@ function(_ep_add_update_command name)
     if(NOT git_tag)
       set(git_tag "master")
     endif()
+    get_property(git_submodules TARGET ${name} PROPERTY _EP_GIT_SUBMODULES)
     _ep_write_gitupdate_script(${tmp_dir}/${name}-gitupdate.cmake
-      ${GIT_EXECUTABLE} ${git_tag} ${git_repository} ${work_dir}
+      ${GIT_EXECUTABLE} ${git_tag} "${git_submodules}" ${git_repository} ${work_dir}
       )
     set(cmd ${CMAKE_COMMAND} -P ${tmp_dir}/${name}-gitupdate.cmake)
     set(always 1)
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index 602ff0f65..d9344eca2 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -512,6 +512,22 @@ if(do_git_tests)
     LOG_UPDATE 1
   )
   set_property(TARGET ${proj} PROPERTY FOLDER "GIT")
+
+  # git by explicit branch/tag with empty submodule list
+  #
+  set(proj TutorialStep1-GIT-bytag-withsubmodules)
+  ExternalProject_Add(${proj}
+    GIT_REPOSITORY "${local_git_repo}"
+    GIT_TAG "origin/master"
+    GIT_SUBMODULES ""
+    UPDATE_COMMAND ""
+    CMAKE_GENERATOR "${CMAKE_GENERATOR}"
+    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
+    INSTALL_COMMAND ""
+    DEPENDS "SetupLocalGITRepository"
+  )
+  set_property(TARGET ${proj} PROPERTY FOLDER "GIT")
+
 endif()
 
 set(do_hg_tests 0)