[pygobject] float converter: use Python API for formatting the error message; add test

[Christoph Reiter <creiter src gnome org>]

commit a408318f53d483263099924ecf586f992aca2f71
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sat Apr 14 20:38:34 2018 +0200

    float converter: use Python API for formatting the error message; add test
    
    We can do this now with pygi_pyerr_format()

 gi/pygi-basictype.c      | 47 +++++++++++++++++++++++++++++++++--------------
 tests/test_everything.py |  7 +++++++
 2 files changed, 40 insertions(+), 14 deletions(-)
---
diff --git a/gi/pygi-basictype.c b/gi/pygi-basictype.c
index 3dab06d5..1067dc2f 100644
--- a/gi/pygi-basictype.c
+++ b/gi/pygi-basictype.c
@@ -97,19 +97,25 @@ pygi_gssize_to_py (gssize value)
     return PYGLIB_PyLong_FromSsize_t (value);
 }
 
+static PyObject *
+base_float_checks (PyObject *object)
+{
+    if (!PyNumber_Check (object)) {
+        PyErr_Format (PyExc_TypeError, "Must be number, not %s",
+                      object->ob_type->tp_name);
+        return NULL;
+    }
+
+    return PyNumber_Float (object);
+}
+
 gboolean
 pygi_gdouble_from_py (PyObject *py_arg, gdouble *result)
 {
     PyObject *py_float;
     gdouble temp;
 
-    if (!PyNumber_Check (py_arg)) {
-        PyErr_Format (PyExc_TypeError, "Must be number, not %s",
-                      py_arg->ob_type->tp_name);
-        return FALSE;
-    }
-
-    py_float = PyNumber_Float (py_arg);
+    py_float = base_float_checks (py_arg);
     if (py_float == NULL)
         return FALSE;
 
@@ -134,21 +140,34 @@ gboolean
 pygi_gfloat_from_py (PyObject *py_arg, gfloat *result)
 {
     gdouble double_;
+    PyObject *py_float;
 
-    if (!pygi_gdouble_from_py (py_arg, &double_))
+    py_float = base_float_checks (py_arg);
+    if (py_float == NULL)
         return FALSE;
 
+    double_ = PyFloat_AsDouble (py_float);
+    if (PyErr_Occurred ()) {
+        Py_DECREF (py_float);
+        return FALSE;
+    }
+
     if ((double_ < -G_MAXFLOAT || double_ > G_MAXFLOAT) &&
             double_ != INFINITY && double_ != -INFINITY && double_ != NAN) {
-        char buf[100];
-
-        /* we need this as PyErr_Format() does not support float types */
-        snprintf (buf, sizeof (buf), "%g not in range %g to %g",
-                  double_, -G_MAXFLOAT, G_MAXFLOAT);
-        PyErr_SetString (PyExc_OverflowError, buf);
+        PyObject *min, *max;
+
+        min = pygi_gfloat_to_py (-G_MAXFLOAT);
+        max = pygi_gfloat_to_py (G_MAXFLOAT);
+        pygi_pyerr_format (
+            PyExc_OverflowError, "%S not in range %S to %S",
+            py_float, min, max);
+        Py_DECREF (min);
+        Py_DECREF (max);
+        Py_DECREF (py_float);
         return FALSE;
     }
 
+    Py_DECREF (py_float);
     *result = (gfloat)double_;
 
     return TRUE;
diff --git a/tests/test_everything.py b/tests/test_everything.py
index 1dec539c..f218928d 100644
--- a/tests/test_everything.py
+++ b/tests/test_everything.py
@@ -10,6 +10,7 @@ import ctypes
 import warnings
 import sys
 import os
+import re
 import platform
 
 import pytest
@@ -378,6 +379,12 @@ class TestEverything(unittest.TestCase):
                          GLib.MINFLOAT)
         self.assertRaises(OverflowError, Everything.test_float, GLib.MAXFLOAT * 2)
 
+        with pytest.raises(
+                OverflowError,
+                match=re.escape("%s not in range %s to %s" % (
+                    GLib.MAXFLOAT * 2, -GLib.MAXFLOAT, GLib.MAXFLOAT))):
+            Everything.test_float(GLib.MAXFLOAT * 2)
+
     def test_double(self):
         self.assertEqual(Everything.test_double(GLib.MAXDOUBLE),
                          GLib.MAXDOUBLE)