%template ordering in interface file

[tmaslach]

I have been working with %template and std_vector and have been running into some issues. I’m running on windows, but I don’t believe this will be platform specific. I also use the following command line to build (don’t think it’s relevant, but I’m adding it just in case):

swig.exe -threads -python -modern -c++ -Iswig\lib\python -Iswig\lib\std -Iswig\lib mod.i

I am currently using swig 2.0.10, but I believe wsfulton as seen this in 3.X as well (I originally sent a swig-devel email).

Here is my interface file, with C++ code baked in to make things easier:

%module(directors="1", allprotected="1") mod

%{
       template<typename T>
       class myTCouple
       {
       public:
              myTCouple() {}
              static T get5c (const std::vector<myTCouple<T> > &l) { return (T) 5; }
       };
       typedef myTCouple<double> myCouple;
       typedef std::vector<myCouple> myCoupleList;

       double get5  (const myCoupleList &l) { return 5; }
       double get5b (const std::vector<myCouple> &l) { return 5; }
%}

%include "std_vector.i"

template<typename T>
class myTCouple
{
public:
       myTCouple();
       static T get5c (const std::vector<myTCouple<T> > &l);
};

typedef myTCouple<double> myCouple;
typedef std::vector<myCouple> myCoupleList;

%template (myCouple) myTCouple < double >;
%template (myCoupleList) std::vector<myCouple>;

double get5 (const myCoupleList &l);
double get5b (const std::vector<myCouple> &l);

And, last of all, here is the python code I’m trying to execute:

from mod import *
lst = [myCouple(), myCouple()]
get5(lst)           # Should print 5
get5b(lst)          # Should print 5
myCouple.get5c(lst) # Should print 5

get5, get5b work. But myCouple.get5c does not..

Here is a slightly modified version (for clarity, getting rid of other answers not relevant to this issue) of William's response (swig-devel, emailed 12/15/2014 2:14AM EST):

However, there is a catch 22 here as myTCouple is used within the myTCouple class itself. SWIG's handling of this is buggy and I suggest you raise a bug report in Github for this case. If you swap the two %template calls around [...], it will work. This is the only workaround I could find and is technically incorrect as the two %template calls are then the wrong way round.

[ojwb]

Still reproducible with current git master (and swapping the order still makes it work).

[ojwb]

There have been quite a few %template-related fixes since Jan 2022 so I retested, but this is still reproducible with current git master (and swapping the order still makes it work).