# Buggy code
def wrap_tmpl_func(render_str):
    def render_tmpl(
        tmplsrc, from_str=False, to_str=False, context=None, tmplpath=None, **kws
    ):
        if context is None:
            context = {}
        # We want explicit context to overwrite the **kws
        kws.update(context)
        context = kws
        assert "opts" in context
        assert "env" in context

        if isinstance(tmplsrc, basestring):
            if from_str:
                tmplstr = tmplsrc
            else:
                with codecs.open(tmplsrc, "r", SLS_ENCODING) as tmplsrc:
                    tmplstr = tmplsrc.read()
        else:  # assume tmplsrc is file-like.
            tmplstr = tmplsrc.read()
            tmplsrc.close()
        try:
            output = render_str(tmplstr, context, tmplpath)
            if salt.utils.is_windows():
                # Write out with Windows newlines
                output = os.linesep.join(output.splitlines())

        except SaltTemplateRenderError as exc:
            return dict(result=False, data=str(exc))
        except Exception:
            return dict(result=False, data=traceback.format_exc())
        else:
            if to_str:  # then render as string
                return dict(result=True, data=output)
            with tempfile.NamedTemporaryFile("wb", delete=False) as outf:
                outf.write(SLS_ENCODER(output)[0])
                # Note: If nothing is replaced or added by the rendering
                #       function, then the contents of the output file will
                #       be exactly the same as the input.
            return dict(result=True, data=outf.name)

    render_tmpl.render_str = render_str
    return render_tmpl


# Traceback (UnicodeDecodeError)
ns2:
----------
State: - file
Name:      /etc/powerdns/zones
Function:  recurse
Result:    False
Comment:   An exception occurred in this state: Traceback (most recent call last):
File "/usr/lib/pymodules/python2.7/salt/state.py", line 1201, in call
*cdata['args'], **cdata['kwargs'])
File "/usr/lib/pymodules/python2.7/salt/states/file.py", line 1317, in recurse
manage_file(dest, src)
File "/usr/lib/pymodules/python2.7/salt/states/file.py", line 1240, in manage_file
**pass_kwargs)
File "/usr/lib/pymodules/python2.7/salt/states/file.py", line 787, in managed
**kwargs
File "/usr/lib/pymodules/python2.7/salt/modules/file.py", line 1340, in check_managed
**kwargs)
File "/usr/lib/pymodules/python2.7/salt/modules/file.py", line 1153, in get_managed
**kwargs
File "/usr/lib/pymodules/python2.7/salt/utils/templates.py", line 53, in render_tmpl
tmplstr = tmplsrc.read()
File "/usr/lib/python2.7/codecs.py", line 671, in read
return self.reader.read(size)
File "/usr/lib/python2.7/codecs.py", line 477, in read
newchars, decodedbytes = self.decode(data, self.errors)
UnicodeDecodeError: 'utf8' codec can't decode byte 0x86 in position 16: invalid start byte

# Fixed code
def wrap_tmpl_func(render_str):
    def render_tmpl(
        tmplsrc, from_str=False, to_str=False, context=None, tmplpath=None, **kws
    ):
        if context is None:
            context = {}
        # We want explicit context to overwrite the **kws
        kws.update(context)
        context = kws
        assert "opts" in context
        assert "env" in context

        if isinstance(tmplsrc, basestring):
            if from_str:
                tmplstr = tmplsrc
            else:
                try:
                    with codecs.open(tmplsrc, "r", SLS_ENCODING) as _tmplsrc:
                        tmplstr = _tmplsrc.read()
                except Exception as exc:
                    log.error(
                        "Exception ocurred while reading file {0}: {1}".format(
                            tmplsrc, exc
                        )
                    )
                    raise exc
        else:  # assume tmplsrc is file-like.
            tmplstr = tmplsrc.read()
            tmplsrc.close()
        try:
            output = render_str(tmplstr, context, tmplpath)
            if salt.utils.is_windows():
                # Write out with Windows newlines
                output = os.linesep.join(output.splitlines())

        except SaltTemplateRenderError as exc:
            return dict(result=False, data=str(exc))
        except Exception:
            return dict(result=False, data=traceback.format_exc())
        else:
            if to_str:  # then render as string
                return dict(result=True, data=output)
            with tempfile.NamedTemporaryFile("wb", delete=False) as outf:
                outf.write(SLS_ENCODER(output)[0])
                # Note: If nothing is replaced or added by the rendering
                #       function, then the contents of the output file will
                #       be exactly the same as the input.
            return dict(result=True, data=outf.name)

    render_tmpl.render_str = render_str
    return render_tmpl