Merge topic 'fix-13392-nmake-empty-depends-problem'

7ae7d66 NMake: Fix problem with empty DEPENDS args (#13392)
078e35d NMake: Add a test to demonstrate EmptyDepends issue (#13392)

Source/cmLocalGenerator.cxx

@@ -1875,6 +1875,14 @@ bool cmLocalGenerator::GetRealDependency(const char* inName,
   // modify the name so stripping down to just the file name should
   // produce the target name in this case.
   std::string name = cmSystemTools::GetFilenameName(inName);
+
+  // If the input name is the empty string, there is no real
+  // dependency. Short-circuit the other checks:
+  if(name == "")
+    {
+    return false;
+    }
+
   if(cmSystemTools::GetFilenameLastExtension(name) == ".exe")
     {
     name = cmSystemTools::GetFilenameWithoutLastExtension(name);

Tests/CMakeLists.txt

@@ -573,6 +573,8 @@ ${CMake_BINARY_DIR}/bin/cmake -DVERSION=master -P ${CMake_SOURCE_DIR}/Utilities/
     )
   list(APPEND TEST_BUILD_DIRS "${CMake_BINARY_DIR}/Tests/CustomCommand")
 
+  ADD_TEST_MACRO(EmptyDepends ${CMAKE_CTEST_COMMAND})
+
   add_test(CustomCommandWorkingDirectory  ${CMAKE_CTEST_COMMAND}
     --build-and-test
     "${CMake_SOURCE_DIR}/Tests/CustomCommandWorkingDirectory"

Tests/EmptyDepends/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 2.8)
+project(EmptyDepends)
+
+include(CTest)
+
+set(extra_dep)
+
+add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/qrc_my.cxx
+  COMMAND ${CMAKE_COMMAND} -E touch "${CMAKE_BINARY_DIR}/qrc_my.cxx"
+  DEPENDS "${extra_dep}" "${CMAKE_BINARY_DIR}/my.qrc")
+
+add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/my.qrc
+  COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/my.qrc)
+
+add_library(qrc SHARED ${CMAKE_BINARY_DIR}/qrc_my.cxx)