From a0d620de829b09c0edf594b2578cfa47e855f695 Mon Sep 17 00:00:00 2001
From: "Daniele E. Domenichelli" <daniele.domenichelli@iit.it>
Date: Wed, 20 May 2015 15:14:17 +0200
Subject: ExternalProject: Fix log when the first arg of commands is "COMMAND"
 (#15567)

---
 Modules/ExternalProject.cmake        |  6 ++++--
 Tests/ExternalProject/CMakeLists.txt | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index 7cf9d79..11a24b8 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -1282,7 +1282,7 @@ endif()
 
   # Wrap multiple 'COMMAND' lines up into a second-level wrapper
   # script so all output can be sent to one log file.
-  if(command MATCHES ";COMMAND;")
+  if(command MATCHES "(^|;)COMMAND;")
     set(code_execute_process "
 ${code_cygpath_make}
 execute_process(COMMAND \${command} RESULT_VARIABLE result)
@@ -1299,7 +1299,9 @@ endif()
     set(sep "")
     foreach(arg IN LISTS command)
       if("x${arg}" STREQUAL "xCOMMAND")
-        set(code "${code}set(command \"${cmd}\")${code_execute_process}")
+        if(NOT "x${cmd}" STREQUAL "x")
+          set(code "${code}set(command \"${cmd}\")${code_execute_process}")
+        endif()
         set(cmd "")
         set(sep "")
       else()
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index d2fa86a..de62ce7 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -492,3 +492,38 @@ message(STATUS "do_cvs_tests='${do_cvs_tests}'")
 message(STATUS "do_svn_tests='${do_svn_tests}'")
 message(STATUS "do_git_tests='${do_git_tests}' GIT_EXECUTABLE='${GIT_EXECUTABLE}'")
 message(STATUS "do_hg_tests='${do_hg_tests}'   HG_EXECUTABLE='${HG_EXECUTABLE}'")
+
+
+# Test if log works when the first arguments of *_COMMAND is "COMMAND".
+set(proj ExternalProject-no-log)
+set(download_cmd "")
+set(patch_cmd "")
+set(update_cmd "")
+set(configure_cmd "")
+set(build_cmd "")
+set(install_cmd "")
+
+ExternalProject_Add(${proj}
+  DOWNLOAD_COMMAND "${download_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "download"
+  PATCH_COMMAND "${patch_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "patch"
+  UPDATE_COMMAND "${update_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "update"
+  CONFIGURE_COMMAND "${configure_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "configure"
+  BUILD_COMMAND "${build_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "build"
+  INSTALL_COMMAND "${install_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "install"
+  )
+
+set(proj ExternalProject-log)
+ExternalProject_Add(${proj}
+  DOWNLOAD_COMMAND "${download_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "download"
+  PATCH_COMMAND "${patch_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "patch"
+  UPDATE_COMMAND "${update_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "update"
+  CONFIGURE_COMMAND "${configure_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "configure"
+  BUILD_COMMAND "${build_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "build"
+  INSTALL_COMMAND "${install_cmd}" COMMAND "${CMAKE_COMMAND}" -E echo "install"
+  LOG_DOWNLOAD 1
+  LOG_PATCH 1
+  LOG_UPDATE 1
+  LOG_CONFIGURE 1
+  LOG_BUILD 1
+  LOG_INSTALL 1
+  )
-- 
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