Export: Escape exported property values when writing CMake language files

When writing export files, correctly encode property values that contain
characters special to the CMake language parser.  We must ensure that
they parse correctly when loaded on the consuming side.
Reported-by: Dan Liew <dan@su-root.co.uk>

Source/cmExportFileGenerator.cxx

@@ -23,11 +23,27 @@
 #include "cmVersion.h"
 #include "cmComputeLinkInformation.h"
 #include "cmAlgorithms.h"
+#include "cmOutputConverter.h"
 
 #include <cmsys/auto_ptr.hxx>
 #include <cmsys/FStream.hxx>
 #include <assert.h>
 
+//----------------------------------------------------------------------------
+static std::string cmExportFileGeneratorEscape(std::string const& str)
+{
+  // Escape a property value for writing into a .cmake file.
+  std::string result = cmOutputConverter::EscapeForCMake(str);
+  // Un-escape variable references generated by our own export code.
+  cmSystemTools::ReplaceString(result,
+                               "\\${_IMPORT_PREFIX}",
+                               "${_IMPORT_PREFIX}");
+  cmSystemTools::ReplaceString(result,
+                               "\\${CMAKE_IMPORT_LIBRARY_SUFFIX}",
+                               "${CMAKE_IMPORT_LIBRARY_SUFFIX}");
+  return result;
+}
+
 //----------------------------------------------------------------------------
 cmExportFileGenerator::cmExportFileGenerator()
 {
@@ -608,7 +624,8 @@ void cmExportFileGenerator::GenerateInterfaceProperties(cmTarget const* target,
     for(ImportPropertyMap::const_iterator pi = properties.begin();
         pi != properties.end(); ++pi)
       {
-      os << "  " << pi->first << " \"" << pi->second << "\"\n";
+      os << "  " << pi->first << " "
+         << cmExportFileGeneratorEscape(pi->second) << "\n";
       }
     os << ")\n\n";
     }
@@ -1112,7 +1129,8 @@ cmExportFileGenerator
   for(ImportPropertyMap::const_iterator pi = properties.begin();
       pi != properties.end(); ++pi)
     {
-    os << "  " << pi->first << " \"" << pi->second << "\"\n";
+    os << "  " << pi->first << " "
+       << cmExportFileGeneratorEscape(pi->second) << "\n";
     }
   os << "  )\n"
      << "\n";
@@ -1223,7 +1241,7 @@ cmExportFileGenerator
     ImportPropertyMap::const_iterator pi = properties.find(*li);
     if (pi != properties.end())
       {
-      os << "\"" << pi->second << "\" ";
+      os << cmExportFileGeneratorEscape(pi->second) << " ";
       }
     }
 

Tests/ExportImport/Export/Interface/CMakeLists.txt

@@ -39,7 +39,11 @@ install(FILES
   DESTINATION src
 )
 
+add_library(cmakeonly INTERFACE)
+set_property(TARGET cmakeonly PROPERTY INTERFACE_COMPILE_DEFINITIONS [[DEF="\"\$\B"]])
+
 install(TARGETS headeronly sharediface use_auto_type use_c_restrict source_target
+                cmakeonly
   EXPORT expInterface
 )
 install(TARGETS sharedlib

Tests/ExportImport/Import/Interface/CMakeLists.txt

@@ -99,3 +99,14 @@ add_executable(interfacetest_exp interfacetest.cpp)
 target_link_libraries(interfacetest_exp exp::sharediface)
 
 do_try_compile(exp)
+
+foreach(ns exp bld)
+  get_property(defs TARGET ${ns}::cmakeonly PROPERTY INTERFACE_COMPILE_DEFINITIONS)
+  if(NOT defs STREQUAL [[DEF="\"\$\B"]])
+    message(SEND_ERROR
+      "${ns}::cmakeonly property INTERFACE_COMPILE_DEFINITIONS is:\n"
+      " ${defs}\n"
+      "not\n"
+      " " [[DEF="\"\$\B"]] "\n")
+  endif()
+endforeach()