ENH: Improve response to bad if or elseif

Previously bad arguments to an if() or elseif() would cause some
subsequent statements in the corresponding block to execute.  This
teaches CMake to stop processing commands with a fatal error.  It also
provides context to bad elseif() error messages.

1 files changed, 19 insertions, 0 deletions

diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 77843e8..6a09042 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -921,5 +921,24 @@ private:
   void EnforceDirectoryLevelRules();
 };
 
+//----------------------------------------------------------------------------
+// Helper class to make sure the call stack is valid.
+class cmMakefileCall
+{
+public:
+  cmMakefileCall(cmMakefile* mf,
+                 cmListFileContext const& lfc,
+                 cmExecutionStatus& status): Makefile(mf)
+    {
+    cmMakefile::CallStackEntry entry = {&lfc, &status};
+    this->Makefile->CallStack.push_back(entry);
+    }
+  ~cmMakefileCall()
+    {
+    this->Makefile->CallStack.pop_back();
+    }
+private:
+  cmMakefile* Makefile;
+};
 
 #endif