Restore support for explicitly referenced CMakeLists.txt sources

Since commit v3.11.0-rc1~467^2 (VS,Xcode: Add CMakeLists.txt sources
without mutating targets, 2017-10-18) we do not add `CMakeLists.txt` to
target sources but instead generate references to them directly.  This
broke projects that explicitly specify their `CMakeLists.txt` file as a
source file because the explicit entry is no longer consolidated with
the generated one.

Teach the relevant generators to avoid duplicating `CMakeLists.txt`
source references and add test cases.

Fixes: #17828

1 files changed, 7 insertions, 0 deletions

diff --git a/Source/cmVisualStudio10TargetGenerator.cxx b/Source/cmVisualStudio10TargetGenerator.cxx
index ec31bd6..8a9df8f 100644
--- a/Source/cmVisualStudio10TargetGenerator.cxx
+++ b/Source/cmVisualStudio10TargetGenerator.cxx
@@ -1898,7 +1898,14 @@ void cmVisualStudio10TargetGenerator::WriteAllSources()
   std::vector<cmGeneratorTarget::AllConfigSource> const& sources =
     this->GeneratorTarget->GetAllConfigSources();
 
+  cmSourceFile const* srcCMakeLists =
+    this->LocalGenerator->CreateVCProjBuildRule();
+
   for (cmGeneratorTarget::AllConfigSource const& si : sources) {
+    if (si.Source == srcCMakeLists) {
+      // Skip explicit reference to CMakeLists.txt source.
+      continue;
+    }
     std::string tool;
     switch (si.Kind) {
       case cmGeneratorTarget::SourceKindAppManifest: