Create CMP0014 to require CMakeLists.txt files

Until now CMake accidentally accepted add_subdirectory() and subdirs()
calls referring to directories that do not contain a CMakeLists.txt
file.  We introduce CMake Policy CMP0014 to make this case an error.

1 files changed, 41 insertions, 1 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 65ea7e7..4d7bfdb 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -167,9 +167,49 @@ void cmLocalGenerator::ComputeObjectMaxPath()
 //----------------------------------------------------------------------------
 void cmLocalGenerator::ReadInputFile()
 {
+  // Look for the CMakeLists.txt file.
   std::string currentStart = this->Makefile->GetStartDirectory();
   currentStart += "/CMakeLists.txt";
-  this->Makefile->ReadListFile(currentStart.c_str());
+  if(cmSystemTools::FileExists(currentStart.c_str(), true))
+    {
+    this->Makefile->ReadListFile(currentStart.c_str());
+    return;
+    }
+
+  if(!this->Parent)
+    {
+    return;
+    }
+
+  // The file is missing.  Check policy CMP0014.
+  cmMakefile* mf = this->Parent->GetMakefile();
+  cmOStringStream e;
+  e << "The source directory\n"
+    << "  " << this->Makefile->GetStartDirectory() << "\n"
+    << "does not contain a CMakeLists.txt file.";
+  switch (mf->GetPolicyStatus(cmPolicies::CMP0014))
+    {
+    case cmPolicies::WARN:
+      // Print the warning.
+      e << "\n"
+        << "CMake does not support this case but it used "
+        << "to work accidentally and is being allowed for "
+        << "compatibility."
+        << "\n"
+        << mf->GetPolicies()->GetPolicyWarning(cmPolicies::CMP0014);
+      mf->IssueMessage(cmake::AUTHOR_WARNING, e.str());
+    case cmPolicies::OLD:
+      // OLD behavior does not warn.
+      return;
+    case cmPolicies::REQUIRED_IF_USED:
+    case cmPolicies::REQUIRED_ALWAYS:
+      e << "\n"
+        << mf->GetPolicies()->GetRequiredPolicyError(cmPolicies::CMP0014);
+    case cmPolicies::NEW:
+      // NEW behavior prints the error.
+      mf->IssueMessage(cmake::FATAL_ERROR, e.str());
+      break;
+    }
 }
 
 void cmLocalGenerator::SetupPathConversions()