PrintHelpers: Fix target SOURCES property

It's been a long-standing bug in CMakePrintHelpers that the
cmake_print_properties() function cannot print the SOURCES
property of a requested TARGET, confusing it with a request
to print properties of SOURCES.

We work around this by parsing the arguments in two stages,
so that a SOURCES that comes after the PROPERTIES keyword
is handled differently from a SOURCES that comes before it.

This adds the restriction that the "mode" keyword (TARGETS
SOURCES DIRECTORIES etc...) and its arguments **must** precede
the PROPERTIES keyword and its arguments. In other words:

1. Both of these are now valid and will be interpreted correctly,
   whereas previously only the first was, and the second caused
   a FATAL_ERROR:

   cmake_print_properties(SOURCES foo.c PROPERTIES LANGUAGE)
   cmake_print_properties(TARGETS foo PROPERTIES SOURCES)

2. This, OTOH, which used to be valid, no longer is, and will
   trigger a FATAL_ERROR:

   cmake_print_properties(PROPERTIES LANGUAGE SOURCES foo.c)

Fixes: #14883

1 files changed, 33 insertions, 16 deletions

diff --git a/Modules/CMakePrintHelpers.cmake b/Modules/CMakePrintHelpers.cmake
index 8c25a73..0af2d3f 100644
--- a/Modules/CMakePrintHelpers.cmake
+++ b/Modules/CMakePrintHelpers.cmake
@@ -56,17 +56,34 @@ endfunction()
 function(cmake_print_properties)
   set(options )
   set(oneValueArgs )
-  set(multiValueArgs TARGETS SOURCES TESTS DIRECTORIES CACHE_ENTRIES PROPERTIES )
+  set(cpp_multiValueArgs PROPERTIES )
+  set(cppmode_multiValueArgs TARGETS SOURCES TESTS DIRECTORIES CACHE_ENTRIES )
 
-  cmake_parse_arguments(CPP "${options}" "${oneValueArgs}" "${multiValueArgs}"  ${ARGN})
+  string(JOIN " " _mode_names ${cppmode_multiValueArgs})
+  set(_missing_mode_message
+    "Mode keyword missing in cmake_print_properties() call, there must be exactly one of ${_mode_names}")
 
-  if(CPP_UNPARSED_ARGUMENTS)
-    message(FATAL_ERROR "Unknown keywords given to cmake_print_properties(): \"${CPP_UNPARSED_ARGUMENTS}\"")
+  cmake_parse_arguments(
+    CPP "${options}" "${oneValueArgs}" "${cpp_multiValueArgs}" ${ARGN})
+
+  if(NOT CPP_PROPERTIES)
+    message(FATAL_ERROR
+      "Required argument PROPERTIES missing in cmake_print_properties() call")
     return()
   endif()
 
-  if(NOT CPP_PROPERTIES)
-    message(FATAL_ERROR "Required argument PROPERTIES missing in cmake_print_properties() call")
+  if(NOT CPP_UNPARSED_ARGUMENTS)
+    message(FATAL_ERROR "${_missing_mode_message}")
+    return()
+  endif()
+
+  cmake_parse_arguments(
+    CPPMODE "${options}" "${oneValueArgs}" "${cppmode_multiValueArgs}"
+    ${CPP_UNPARSED_ARGUMENTS})
+
+  if(CPPMODE_UNPARSED_ARGUMENTS)
+    message(FATAL_ERROR
+      "Unknown keywords given to cmake_print_properties(): \"${CPPMODE_UNPARSED_ARGUMENTS}\"")
     return()
   endif()
 
@@ -74,32 +91,32 @@ function(cmake_print_properties)
   set(items)
   set(keyword)
 
-  if(CPP_TARGETS)
-    set(items ${CPP_TARGETS})
+  if(CPPMODE_TARGETS)
+    set(items ${CPPMODE_TARGETS})
     set(mode ${mode} TARGETS)
     set(keyword TARGET)
   endif()
 
-  if(CPP_SOURCES)
-    set(items ${CPP_SOURCES})
+  if(CPPMODE_SOURCES)
+    set(items ${CPPMODE_SOURCES})
     set(mode ${mode} SOURCES)
     set(keyword SOURCE)
   endif()
 
-  if(CPP_TESTS)
-    set(items ${CPP_TESTS})
+  if(CPPMODE_TESTS)
+    set(items ${CPPMODE_TESTS})
     set(mode ${mode} TESTS)
     set(keyword TEST)
   endif()
 
-  if(CPP_DIRECTORIES)
-    set(items ${CPP_DIRECTORIES})
+  if(CPPMODE_DIRECTORIES)
+    set(items ${CPPMODE_DIRECTORIES})
     set(mode ${mode} DIRECTORIES)
     set(keyword DIRECTORY)
   endif()
 
-  if(CPP_CACHE_ENTRIES)
-    set(items ${CPP_CACHE_ENTRIES})
+  if(CPPMODE_CACHE_ENTRIES)
+    set(items ${CPPMODE_CACHE_ENTRIES})
     set(mode ${mode} CACHE_ENTRIES)
     # This is a workaround for the fact that passing `CACHE` as an argument to
     # set() causes a cache variable to be set.