Replaced boost::filesystem::canonical() with boost::filesystem::absol…

…ute(),

as canonical() is broken on Windows (reparse points aka symbolic links
are not processed correctly).

Fixes
#732
#3956
#4557

src/libslic3r/Preset.cpp

@@ -634,7 +634,9 @@ void PresetCollection::add_default_preset(const std::vector<std::string> &keys,
 // Throws an exception on error.
 void PresetCollection::load_presets(const std::string &dir_path, const std::string &subdir)
 {
-    boost::filesystem::path dir = boost::filesystem::canonical(boost::filesystem::path(dir_path) / subdir).make_preferred();
+    // Don't use boost::filesystem::canonical() on Windows, it is broken in regard to reparse points, 
+    // see https://github.com/prusa3d/PrusaSlicer/issues/732
+    boost::filesystem::path dir = boost::filesystem::absolute(boost::filesystem::path(dir_path) / subdir).make_preferred();
     m_dir_path = dir.string();
     std::string errors_cummulative;
     // Store the loaded presets into a new vector, otherwise the binary search for already existing presets would be broken.
@@ -1518,7 +1520,9 @@ PhysicalPrinterCollection::PhysicalPrinterCollection( const std::vector<std::str
 // Throws an exception on error.
 void PhysicalPrinterCollection::load_printers(const std::string& dir_path, const std::string& subdir)
 {
-    boost::filesystem::path dir = boost::filesystem::canonical(boost::filesystem::path(dir_path) / subdir).make_preferred();
+    // Don't use boost::filesystem::canonical() on Windows, it is broken in regard to reparse points, 
+    // see https://github.com/prusa3d/PrusaSlicer/issues/732
+    boost::filesystem::path dir = boost::filesystem::absolute(boost::filesystem::path(dir_path) / subdir).make_preferred();
     m_dir_path = dir.string();
     std::string errors_cummulative;
     // Store the loaded printers into a new vector, otherwise the binary search for already existing presets would be broken.