cmake: tidy-up foreach() syntax

Use `IN LISTS` and `IN ITEMS`. This appears to be the preferred way
within CMake's own source code and possibly improves readability.

Fixup a side-effect of `IN LISTS`, where it retains empty values at
the end of the list, as opposed to the syntax used before, which
dropped it. In our case this happened with lines read from a text
file via `file(READ)`.

https://cmake.org/cmake/help/v3.7/command/foreach.html

Closes libssh2#1180

Author: vszakats

cmake/CheckFunctionExistsMayNeedLibrary.cmake

@@ -65,7 +65,7 @@ function(check_function_exists_may_need_library function variable)
   check_function_exists(${function} ${variable})
 
   if(NOT ${variable})
-    foreach(lib ${ARGN})
+    foreach(lib IN LISTS ARGN)
       string(TOUPPER ${lib} UP_LIB)
       # Use new variable to prevent cache from previous step shortcircuiting
       # new test

cmake/CopyRuntimeDependencies.cmake

@@ -52,12 +52,11 @@ function(ADD_TARGET_TO_COPY_DEPENDENCIES)
   # parallel builds trying to kick off the commands at the same time
   add_custom_target(${COPY_TARGET})
 
-  foreach(target ${COPY_BEFORE_TARGETS})
+  foreach(target IN LISTS COPY_BEFORE_TARGETS)
     add_dependencies(${target} ${COPY_TARGET})
   endforeach()
 
-  foreach(dependency ${COPY_DEPENDENCIES})
-
+  foreach(dependency IN LISTS COPY_DEPENDENCIES)
     add_custom_command(
       TARGET ${COPY_TARGET}
       DEPENDS ${dependency}
@@ -68,7 +67,5 @@ function(ADD_TARGET_TO_COPY_DEPENDENCIES)
       COMMAND ${CMAKE_COMMAND}
       ARGS -E copy ${dependency} ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}
       VERBATIM)
-
   endforeach()
-
 endfunction()

cmake/max_warnings.cmake

@@ -189,11 +189,11 @@ elseif(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_C_COMPILER_I
 
     unset(WPICKY)
 
-    foreach(_CCOPT ${WPICKY_ENABLE})
+    foreach(_CCOPT IN LISTS WPICKY_ENABLE)
       set(WPICKY "${WPICKY} ${_CCOPT}")
     endforeach()
 
-    foreach(_CCOPT ${WPICKY_DETECT})
+    foreach(_CCOPT IN LISTS WPICKY_DETECT)
       # surprisingly, CHECK_C_COMPILER_FLAG needs a new variable to store each new
       # test result in.
       string(MAKE_C_IDENTIFIER "OPT${_CCOPT}" _optvarname)

example/CMakeLists.txt

@@ -45,7 +45,7 @@ transform_makefile_inc("Makefile.am" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.am.cm
 include("${CMAKE_CURRENT_BINARY_DIR}/Makefile.am.cmake")
 set(EXAMPLES ${noinst_PROGRAMS})
 
-foreach(example ${EXAMPLES})
+foreach(example IN LISTS EXAMPLES)
   add_executable(${example} "${example}.c")
   list(APPEND EXAMPLE_TARGETS ${example})
   # to find generated header

tests/CMakeLists.txt

@@ -74,7 +74,7 @@ add_library(runner STATIC ${librunner_la_SOURCES})
 target_compile_definitions(runner PRIVATE "${CRYPTO_BACKEND_DEFINE}")
 target_include_directories(runner PRIVATE "${CMAKE_CURRENT_BINARY_DIR}/../src" "../src" "../include" "${CRYPTO_BACKEND_INCLUDE_DIR}")
 
-foreach(test ${DOCKER_TESTS} ${STANDALONE_TESTS} ${SSHD_TESTS})
+foreach(test IN LISTS DOCKER_TESTS STANDALONE_TESTS SSHD_TESTS)
   if(NOT ";${DOCKER_TESTS_STATIC};${STANDALONE_TESTS_STATIC};" MATCHES ";${test};")
     set(LIB_FOR_TESTS ${LIB_SELECTED})
   elseif(TARGET ${LIB_STATIC})
@@ -107,15 +107,15 @@ endforeach()
 option(RUN_DOCKER_TESTS "Run tests requiring Docker" ON)
 
 if(RUN_DOCKER_TESTS)
-  foreach(test ${DOCKER_TESTS})
+  foreach(test IN LISTS DOCKER_TESTS)
     if(TARGET ${test})
       add_test(NAME ${test} COMMAND "$<TARGET_FILE:${test}>")
       set_property(TEST ${test} APPEND PROPERTY ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}")
     endif()
   endforeach()
 endif()
 
-foreach(test ${STANDALONE_TESTS})
+foreach(test IN LISTS STANDALONE_TESTS)
   if(TARGET ${test})
     add_test(NAME ${test} COMMAND "$<TARGET_FILE:${test}>")
     set_property(TEST ${test} APPEND PROPERTY ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}")
@@ -124,7 +124,7 @@ endforeach()
 
 if(RUN_SSHD_TESTS AND SSHD_EXECUTABLE)
   unset(sshd_test_targets)
-  foreach(test ${SSHD_TESTS})
+  foreach(test IN LISTS SSHD_TESTS)
     if(TARGET ${test})
       set(sshd_test_targets "${sshd_test_targets} $<TARGET_FILE:${test}>")
     endif()
@@ -141,14 +141,16 @@ if(RUN_DOCKER_TESTS)
   # CRYPT/MAC algo tests
   file(READ "test_read_algos.txt" ALGO_TESTS)
   string(REGEX REPLACE "\\\n" ";" ALGO_TESTS ${ALGO_TESTS})
-  foreach(test ${ALGO_TESTS})
-    set(testname "test_read-${test}")
-    add_test(NAME ${testname} COMMAND "$<TARGET_FILE:test_read>")
-    set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}")
-    if(test MATCHES "mac-")
-      set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "FIXTURE_TEST_MAC=${test}")
-    else()
-      set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "FIXTURE_TEST_CRYPT=${test}")
+  foreach(test IN LISTS ALGO_TESTS)
+    if(test)
+      set(testname "test_read-${test}")
+      add_test(NAME ${testname} COMMAND "$<TARGET_FILE:test_read>")
+      set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}")
+      if(test MATCHES "mac-")
+        set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "FIXTURE_TEST_MAC=${test}")
+      else()
+        set_property(TEST ${testname} APPEND PROPERTY ENVIRONMENT "FIXTURE_TEST_CRYPT=${test}")
+      endif()
     endif()
   endforeach()
 endif()

tests/cmake/CMakeLists.txt

@@ -20,7 +20,7 @@ if(TEST_INTEGRATION_MODE STREQUAL "find_package" OR
       DOWNLOAD_EXTRACT_TIMESTAMP ON)
   endif()
   find_package(libssh2 REQUIRED CONFIG)
-  foreach(result_var libssh2_FOUND libssh2_VERSION)
+  foreach(result_var IN ITEMS libssh2_FOUND libssh2_VERSION)
     if(${result_var})
       message(STATUS "${result_var}: |${${result_var}}|")
     else()