gh-133895: Include computed result value in math and cmath error exceptions

Author: abhigyan631

Lib/test/test_math_errors.py

@@ -0,0 +1,71 @@
+import unittest
+import math
+import cmath
+
+class TestMathErrors(unittest.TestCase):
+    def test_math_value_error_with_value(self):
+        # Test math.sqrt with negative number
+        try:
+            math.sqrt(-1)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(math.isnan(e.value))
+
+        # Test math.log with negative number
+        try:
+            math.log(-1)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(math.isnan(e.value))
+
+        # Test math.acos with value > 1
+        try:
+            math.acos(2)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(math.isnan(e.value))
+
+    def test_cmath_value_error_with_value(self):
+        # Test cmath.sqrt with negative number
+        try:
+            cmath.sqrt(-1)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(isinstance(e.value, complex))
+            self.assertTrue(cmath.isnan(e.value))
+
+        # Test cmath.log with negative number
+        try:
+            cmath.log(-1)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(isinstance(e.value, complex))
+            self.assertTrue(cmath.isnan(e.value))
+
+        # Test cmath.acos with value > 1
+        try:
+            cmath.acos(2)
+        except ValueError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(isinstance(e.value, complex))
+            self.assertTrue(cmath.isnan(e.value))
+
+    def test_math_overflow_error_with_value(self):
+        # Test math.exp with very large number
+        try:
+            math.exp(1000)
+        except OverflowError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(math.isinf(e.value))
+
+    def test_cmath_overflow_error_with_value(self):
+        # Test cmath.exp with very large number
+        try:
+            cmath.exp(1000)
+        except OverflowError as e:
+            self.assertTrue(hasattr(e, 'value'))
+            self.assertTrue(isinstance(e.value, complex))
+            self.assertTrue(cmath.isinf(e.value.real) or cmath.isinf(e.value.imag))
+
+if __name__ == '__main__':
+    unittest.main() 

Modules/cmathmodule.c

@@ -35,11 +35,23 @@ class Py_complex_protected_return_converter(CReturnConverter):
         self.declare(data)
         data.return_conversion.append("""
 if (errno == EDOM) {
-    PyErr_SetString(PyExc_ValueError, "math domain error");
+    PyObject *exc = PyErr_GetRaisedException();
+    PyObject *value = PyComplex_FromCComplex(_return_value);
+    if (value) {
+        PyObject_SetAttrString(exc, "value", value);
+    }
+    Py_DECREF(value);
+    PyErr_SetRaisedException(exc);
     goto exit;
 }
 else if (errno == ERANGE) {
-    PyErr_SetString(PyExc_OverflowError, "math range error");
+    PyObject *exc = PyErr_GetRaisedException();
+    PyObject *value = PyComplex_FromCComplex(_return_value);
+    if (value) {
+        PyObject_SetAttrString(exc, "value", value);
+    }
+    Py_DECREF(value);
+    PyErr_SetRaisedException(exc);
     goto exit;
 }
 else {
@@ -408,8 +420,8 @@ cmath_cosh_impl(PyObject *module, Py_complex z)
 
     /* special treatment for cosh(+/-inf + iy) if y is not a NaN */
     if (!isfinite(z.real) || !isfinite(z.imag)) {
-        if (isinf(z.real) && isfinite(z.imag) &&
-            (z.imag != 0.)) {
+        if (isinf(z.real) && isfinite(z.imag)
+            && (z.imag != 0.)) {
             if (z.real > 0) {
                 r.real = copysign(INF, cos(z.imag));
                 r.imag = copysign(INF, sin(z.imag));
@@ -899,10 +911,24 @@ cmath_log_impl(PyObject *module, Py_complex x, PyObject *y_obj)
 static PyObject *
 math_error(void)
 {
-    if (errno == EDOM)
-        PyErr_SetString(PyExc_ValueError, "math domain error");
-    else if (errno == ERANGE)
-        PyErr_SetString(PyExc_OverflowError, "math range error");
+    if (errno == EDOM) {
+        PyObject *exc = PyErr_GetRaisedException();
+        PyObject *value = PyComplex_FromCComplex(_return_value);
+        if (value) {
+            PyObject_SetAttrString(exc, "value", value);
+        }
+        Py_DECREF(value);
+        PyErr_SetRaisedException(exc);
+    }
+    else if (errno == ERANGE) {
+        PyObject *exc = PyErr_GetRaisedException();
+        PyObject *value = PyComplex_FromCComplex(_return_value);
+        if (value) {
+            PyObject_SetAttrString(exc, "value", value);
+        }
+        Py_DECREF(value);
+        PyErr_SetRaisedException(exc);
+    }
     else    /* Unexpected math error */
         PyErr_SetFromErrno(PyExc_ValueError);
     return NULL;
@@ -1338,3 +1364,33 @@ PyInit_cmath(void)
 {
     return PyModuleDef_Init(&cmathmodule);
 }
+
+static int
+Py_complex_protected_return_converter(PyObject *obj, void *ptr)
+{
+    Py_complex *p = (Py_complex *)ptr;
+    if (PyComplex_Check(obj)) {
+        *p = PyComplex_AsCComplex(obj);
+        return 1;
+    }
+    if (PyFloat_Check(obj)) {
+        p->real = PyFloat_AsDouble(obj);
+        p->imag = 0.0;
+        return 1;
+    }
+    if (PyLong_Check(obj)) {
+        p->real = PyLong_AsDouble(obj);
+        p->imag = 0.0;
+        return 1;
+    }
+    if (PyErr_Occurred()) {
+        PyObject *exc = PyErr_GetRaisedException();
+        PyObject *value = PyComplex_FromCComplex(*p);
+        if (value) {
+            PyObject_SetAttrString(exc, "value", value);
+        }
+        Py_DECREF(value);
+        PyErr_SetRaisedException(exc);
+    }
+    return 0;
+}

Modules/mathmodule.c

@@ -83,7 +83,7 @@ module math
 Double and triple length extended precision algorithms from:
 
   Accurate Sum and Dot Product
-  by Takeshi Ogita, Siegfried M. Rump, and Shin’Ichi Oishi
+  by Takeshi Ogita, Siegfried M. Rump, and Shin'Ichi Oishi
   https://doi.org/10.1137/030601818
   https://www.tuhh.de/ti3/paper/rump/OgRuOi05.pdf
 
@@ -847,44 +847,31 @@ math_lcm_impl(PyObject *module, PyObject * const *args,
 static int
 is_error(double x, int raise_edom)
 {
-    int result = 1;     /* presumption of guilt */
-    assert(errno);      /* non-zero errno is a precondition for calling */
-    if (errno == EDOM) {
+    if (Py_IS_NAN(x)) {
         if (raise_edom) {
-            PyErr_SetString(PyExc_ValueError, "math domain error");
+            PyObject *exc = PyErr_GetRaisedException();
+            PyObject *value = PyFloat_FromDouble(x);
+            if (value) {
+                PyObject_SetAttrString(exc, "value", value);
+            }
+            Py_DECREF(value);
+            PyErr_SetRaisedException(exc);
         }
+        return 1;
     }
-
-    else if (errno == ERANGE) {
-        /* ANSI C generally requires libm functions to set ERANGE
-         * on overflow, but also generally *allows* them to set
-         * ERANGE on underflow too.  There's no consistency about
-         * the latter across platforms.
-         * Alas, C99 never requires that errno be set.
-         * Here we suppress the underflow errors (libm functions
-         * should return a zero on underflow, and +- HUGE_VAL on
-         * overflow, so testing the result for zero suffices to
-         * distinguish the cases).
-         *
-         * On some platforms (Ubuntu/ia64) it seems that errno can be
-         * set to ERANGE for subnormal results that do *not* underflow
-         * to zero.  So to be safe, we'll ignore ERANGE whenever the
-         * function result is less than 1.5 in absolute value.
-         *
-         * bpo-46018: Changed to 1.5 to ensure underflows in expm1()
-         * are correctly detected, since the function may underflow
-         * toward -1.0 rather than 0.0.
-         */
-        if (fabs(x) < 1.5)
-            result = 0;
-        else
-            PyErr_SetString(PyExc_OverflowError,
-                            "math range error");
+    if (Py_IS_INFINITY(x)) {
+        if (raise_edom) {
+            PyObject *exc = PyErr_GetRaisedException();
+            PyObject *value = PyFloat_FromDouble(x);
+            if (value) {
+                PyObject_SetAttrString(exc, "value", value);
+            }
+            Py_DECREF(value);
+            PyErr_SetRaisedException(exc);
+        }
+        return 1;
     }
-    else
-        /* Unexpected math error */
-        PyErr_SetFromErrno(PyExc_ValueError);
-    return result;
+    return 0;
 }
 
 /*