[lmi] boost::filesystem anomaly?

[Greg Chicares]

What should this print under msw?
  std::string s("C:/opt/lmi/bin");
  fs::path g(s, fs::no_check);
  std::cout << g.string() << std::endl;
I think it should print
  C:/opt/lmi/bin <-- expected
and not
  C:opt/lmi/bin <-- unexpected: first slash deleted

With the first patch[0] below, I run lmi and get:
  g is 'C:opt/lmi/bin'
  g is 'C:opt/lmi/bin'
in two successive messageboxes. Note that the third character ("/")
of the original string is missing. (I think that's wrong.)

With the second patch[1] below, I run the unit test and get:
  Running path_utility_test:
  g is 'C:/opt/lmi/bin'
  g is 'C:/opt/lmi/bin'
Here, the third character ("/") is preserved. (I think that's right.)

I noticed this behavior difference when I tried constructing fs::path
objects from input strings. If I did that in GUI code that is part of
$(skeleton_objects), the slash was deleted. If I did that in liblmi.dll
code that is part of $(lmi_common_objects), the slash was *not* deleted.
I guessed that the explanation must be that the GUI code called
initialize_filesystem(), which does this:
    fs::path::default_name_check(fs::native);
even though that shouldn't matter because the fs::path objects are
constructed with fs::no_check; but the patches below seem to rule out
that hypothesis.

This matters because I would like to use fs::path in these functions:
  Transfer(transfer_direction td, std::string& data, wxFilePickerCtrl& control)
  Transfer(transfer_direction td, std::string& data, wxDirPickerCtrl& control)
and that seems to work only if I construct the fs::path in a function
defined in liblmi.dll, but that seems fragile because of the anomaly
demonstrated in the patches.

---------

[0] "the first patch":

----------8<----------
diff --git a/main_wx.cpp b/main_wx.cpp
index 8fa105b..1db6628 100644
--- a/main_wx.cpp
+++ b/main_wx.cpp
@@ -86,8 +86,18 @@ int WINAPI WinMain

     try
         {
+    {
+    std::string s("C:/opt/lmi/bin");
+    fs::path g(s, fs::no_check);
+    warning() << "g is '" << g.string() << "'" << std::flush;
+    }
         initialize_application();
         initialize_filesystem();
+    {
+    std::string s("C:/opt/lmi/bin");
+    fs::path g(s, fs::no_check);
+    warning() << "g is '" << g.string() << "'" << std::flush;
+    }
 #ifndef LMI_MSW
         result = wxEntry(argc, argv);
 #else // LMI_MSW defined.

---------->8----------

[1] "the second patch":

diff --git a/path_utility_test.cpp b/path_utility_test.cpp
index f1c557a..2287320 100644
--- a/path_utility_test.cpp
+++ b/path_utility_test.cpp
@@ -302,8 +302,21 @@ void test_path_validation()
     fs::remove("path_utility_test_file");
 }

+#include "alert.hpp"
 int test_main(int, char*[])
 {
+    {
+    std::string s("C:/opt/lmi/bin");
+    fs::path g(s, fs::no_check);
+    warning() << "g is '" << g.string() << "'" << std::flush;
+    }
+        initialize_filesystem();
+    {
+    std::string s("C:/opt/lmi/bin");
+    fs::path g(s, fs::no_check);
+    warning() << "g is '" << g.string() << "'" << std::flush;
+    }
+
     test_orthodox_filename();
     test_serial_file_path();
     test_unique_filepath_with_normal_filenames();