ExternalProject: Prevent COMMAND from being treated as a true keyword

The known keywords for each function are obtained by scraping the
documentation for lines matching a particular regular expression. In
commit 8842a027 (ExternalProject: Improve documentation, 2017-07-09),
the docs were overhauled and the COMMAND docs subsequently matched the
regular expression when they shouldn't have. This made COMMAND appear as
a true keyword, which thwarted the special handling logic elsewhere for
the intended use of COMMAND arguments.

This commit contains a workaround for issue #17229 to force a dependency
of the patch step on the update step to ensure a predictable step order.

Fixes: #17198

1 files changed, 30 insertions, 0 deletions

diff --git a/Tests/RunCMake/ExternalProject/MultiCommand.cmake b/Tests/RunCMake/ExternalProject/MultiCommand.cmake
new file mode 100644
index 0000000..a8dbfea
--- /dev/null
+++ b/Tests/RunCMake/ExternalProject/MultiCommand.cmake
@@ -0,0 +1,30 @@
+cmake_minimum_required(VERSION 3.9)
+
+include(ExternalProject)
+
+# Verify COMMAND keyword is recognised after various *_COMMAND options
+ExternalProject_Add(multiCommand
+  DOWNLOAD_COMMAND  "${CMAKE_COMMAND}" -E echo "download 1"
+           COMMAND  "${CMAKE_COMMAND}" -E echo "download 2"
+  UPDATE_COMMAND    "${CMAKE_COMMAND}" -E echo "update 1"
+         COMMAND    "${CMAKE_COMMAND}" -E echo "update 2"
+  PATCH_COMMAND     "${CMAKE_COMMAND}" -E echo "patch 1"
+        COMMAND     "${CMAKE_COMMAND}" -E echo "patch 2"
+  CONFIGURE_COMMAND "${CMAKE_COMMAND}" -E echo "configure 1"
+            COMMAND "${CMAKE_COMMAND}" -E echo "configure 2"
+  BUILD_COMMAND     "${CMAKE_COMMAND}" -E echo "build 1"
+        COMMAND     "${CMAKE_COMMAND}" -E echo "build 2"
+  TEST_COMMAND      "${CMAKE_COMMAND}" -E echo "test 1"
+       COMMAND      "${CMAKE_COMMAND}" -E echo "test 2"
+  INSTALL_COMMAND   "${CMAKE_COMMAND}" -E echo "install 1"
+          COMMAND   "${CMAKE_COMMAND}" -E echo "install 2"
+)
+
+# Workaround for issue 17229 (missing dependency between update and patch steps)
+ExternalProject_Add_StepTargets(multiCommand NO_DEPENDS update)
+ExternalProject_Add_StepDependencies(multiCommand patch multiCommand-update)
+
+# Force all steps to be re-run by removing timestamps from any previous run
+ExternalProject_Get_Property(multiCommand STAMP_DIR)
+file(REMOVE_RECURSE "${STAMP_DIR}")
+file(MAKE_DIRECTORY "${STAMP_DIR}")