Correctly implement str + tstring

Author: lysnikolaou

Include/internal/pycore_template.h

@@ -14,6 +14,8 @@ extern "C" {
 extern PyTypeObject _PyTemplate_Type;
 extern PyTypeObject _PyTemplateIter_Type;
 
+extern PyObject *_PyTemplate_Concat(PyObject *self, PyObject *other);
+
 PyAPI_FUNC(PyObject *) _PyTemplate_FromValues(PyObject **values, Py_ssize_t n);
 PyAPI_FUNC(PyObject *) _PyTemplate_FromListStackRef(_PyStackRef ref);
 

Objects/templateobject.c

@@ -341,9 +341,9 @@ template_concat_templates(templateobject *self, templateobject *other)
 }
 
 static PyObject *
-template_concat_template_str(templateobject *self, PyObject *str)
+template_concat_template_str(templateobject *self, PyObject *other)
 {
-    PyObject *newstrings = template_strings_append_str(self->strings, str);
+    PyObject *newstrings = template_strings_append_str(self->strings, other);
     if (newstrings == NULL) {
         return NULL;
     }
@@ -358,9 +358,9 @@ template_concat_template_str(templateobject *self, PyObject *str)
 }
 
 static PyObject *
-template_concat_str_template(templateobject *self, PyObject *str)
+template_concat_str_template(templateobject *self, PyObject *other)
 {
-    PyObject *newstrings = template_strings_prepend_str(self->strings, str);
+    PyObject *newstrings = template_strings_prepend_str(self->strings, other);
     if (newstrings == NULL) {
         return NULL;
     }
@@ -374,8 +374,8 @@ template_concat_str_template(templateobject *self, PyObject *str)
     return template_from_strings_interpolations(Py_TYPE(self), newstrings, newinterpolations);
 }
 
-static PyObject *
-template_concat(PyObject *self, PyObject *other)
+PyObject *
+_PyTemplate_Concat(PyObject *self, PyObject *other)
 {
     if (PyObject_TypeCheck(self, &_PyTemplate_Type) &&
             PyObject_TypeCheck(other, &_PyTemplate_Type)) {
@@ -433,7 +433,7 @@ static PyGetSetDef template_getset[] = {
 };
 
 static PySequenceMethods template_as_sequence = {
-    .sq_concat = template_concat,
+    .sq_concat = _PyTemplate_Concat,
 };
 
 PyTypeObject _PyTemplate_Type = {

Objects/unicodeobject.c

@@ -58,6 +58,7 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "pycore_ucnhash.h"       // _PyUnicode_Name_CAPI
 #include "pycore_unicodeobject.h" // struct _Py_unicode_state
 #include "pycore_unicodeobject_generated.h"  // _PyUnicode_InitStaticStrings()
+#include "pycore_template.h"      // _PyTemplate_Type
 
 #include "stringlib/eq.h"         // unicode_eq()
 #include <stddef.h>               // ptrdiff_t
@@ -11614,10 +11615,16 @@ PyUnicode_Concat(PyObject *left, PyObject *right)
         return NULL;
 
     if (!PyUnicode_Check(right)) {
-        PyErr_Format(PyExc_TypeError,
-                     "can only concatenate str (not \"%.200s\") to str",
-                     Py_TYPE(right)->tp_name);
-        return NULL;
+        if (PyObject_TypeCheck(right, &_PyTemplate_Type)) {
+            // str + tstring is implemented in the tstring type
+            return _PyTemplate_Concat(left, right);
+        }
+        else {
+            PyErr_Format(PyExc_TypeError,
+                "can only concatenate str (not \"%.200s\") to str",
+                Py_TYPE(right)->tp_name);
+            return NULL;
+        }
     }
 
     /* Shortcuts */