#1309 generated tcl code crashes -- easy fix

[Stephen Ehmann]

int removeIndex(std::vector<int> indices);</int>

gives code like this:

      {
        Tcl_Obj **listobjv;
        int       nitems;
        int         temp;
        std::vector<int> *v;

        if(SWIG_ConvertPtr(argv[1], (void **) &v, \
            SWIGTYPE_p_std__vectorTint_t, 0) == 0){
          /* wrapped vector */
          _v = 1;
        } else {
          // It isn't a vector<int> so it should be a list of int's
          if(Tcl_ListObjGetElements(interp, argv[1],
              &nitems, &listobjv) == TCL_ERROR)
          _v = 0;
          else
          if (nitems == 0)
          _v = 1;
          //check the first value to see if it is of correct type
          if (Tcl_GetIntFromObj(interp, listobjv[0], &temp) == TCL_ERROR)
          _v = 0;
          else
          _v = 1;
        }

Notice that the nitems == 0 test will not prevent the Tcl_GetIntFromObj to access listobjv[0] which causes a crash.

[Stephen Ehmann]

I also have this in my .i:
%template(intVector) std::vector<int>;
in case that matters</int>

[Olly Betts]

I've committed a fix which should be in SWIG 4.2.0:

commit 6f4adde4b4dccbd31725aeda1c9e17b9178a5550 (HEAD -> master)
Author: Olly Betts <olly@survex.com>
Date:   Tue Feb 1 13:08:13 2022 +1300

    [Tcl] Fix std_vector typecheck typemaps

    In some cases the typecheck typemap would try to access the first
    element of an empty Tcl list.

    Fixes https://sourceforge.net/p/swig/bugs/1309/