Raise InvalidOperation if exponents of zeros are clamped during exact

Stefan Krah · Stefan Krah · commit 0774e9b9f571 · 2012-04-05T15:21:58.000+02:00
conversion in the Decimal constructor. Exact here refers to the
representation and not to the value (clamping does not change the value).
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
@@ -4953,6 +4953,30 @@ def get_fmt(x, override=None, fmt='n'):
         self.assertRaises(ValueError, get_fmt, 12345, invalid_dot, 'g')
         self.assertRaises(ValueError, get_fmt, 12345, invalid_sep, 'g')
 
+    def test_exact_conversion(self):
+        Decimal = C.Decimal
+        localcontext = C.localcontext
+        InvalidOperation = C.InvalidOperation
+
+        with localcontext() as c:
+
+            c.traps[InvalidOperation] = True
+
+            # Clamped
+            x = "0e%d" % sys.maxsize
+            self.assertRaises(InvalidOperation, Decimal, x)
+
+            x = "0e%d" % (-sys.maxsize-1)
+            self.assertRaises(InvalidOperation, Decimal, x)
+
+            # Overflow
+            x = "1e%d" % sys.maxsize
+            self.assertRaises(InvalidOperation, Decimal, x)
+
+            # Underflow
+            x = "1e%d" % (-sys.maxsize-1)
+            self.assertRaises(InvalidOperation, Decimal, x)
+
 
 all_tests = [
   CExplicitConstructionTest, PyExplicitConstructionTest,
diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
@@ -1935,7 +1935,7 @@ PyDecType_FromCStringExact(PyTypeObject *type, const char *s,
     mpd_maxcontext(&maxctx);
 
     mpd_qset_string(MPD(dec), s, &maxctx, &status);
-    if (status & (MPD_Inexact|MPD_Rounded)) {
+    if (status & (MPD_Inexact|MPD_Rounded|MPD_Clamped)) {
         /* we want exact results */
         mpd_seterror(MPD(dec), MPD_Invalid_operation, &status);
     }
@@ -2139,7 +2139,7 @@ PyDecType_FromLongExact(PyTypeObject *type, const PyObject *pylong,
         return NULL;
     }
 
-    if (status & (MPD_Inexact|MPD_Rounded)) {
+    if (status & (MPD_Inexact|MPD_Rounded|MPD_Clamped)) {
         /* we want exact results */
         mpd_seterror(MPD(dec), MPD_Invalid_operation, &status);
     }
diff --git a/Modules/_decimal/tests/deccheck.py b/Modules/_decimal/tests/deccheck.py
@@ -302,6 +302,7 @@ def RestrictedDecimal(value):
     dec = maxcontext.create_decimal(value)
     if maxcontext.flags[P.Inexact] or \
        maxcontext.flags[P.Rounded] or \
+       maxcontext.flags[P.Clamped] or \
        maxcontext.flags[P.InvalidOperation]:
         return context.p._raise_error(P.InvalidOperation)
     if maxcontext.flags[P.FloatOperation]:

Original file line number	Diff line number	Diff line change
`@@ -1935,7 +1935,7 @@ PyDecType_FromCStringExact(PyTypeObject type, const char s,`
`1935`	`1935`	`mpd_maxcontext(&maxctx);`
`1936`	`1936`
`1937`	`1937`	`mpd_qset_string(MPD(dec), s, &maxctx, &status);`
`1938`		`- if (status & (MPD_Inexact\|MPD_Rounded)) {`
	`1938`	`+ if (status & (MPD_Inexact\|MPD_Rounded\|MPD_Clamped)) {`
`1939`	`1939`	`/* we want exact results */`
`1940`	`1940`	`mpd_seterror(MPD(dec), MPD_Invalid_operation, &status);`
`1941`	`1941`	`}`
`@@ -2139,7 +2139,7 @@ PyDecType_FromLongExact(PyTypeObject type, const PyObject pylong,`
`2139`	`2139`	`return NULL;`
`2140`	`2140`	`}`
`2141`	`2141`
`2142`		`- if (status & (MPD_Inexact\|MPD_Rounded)) {`
	`2142`	`+ if (status & (MPD_Inexact\|MPD_Rounded\|MPD_Clamped)) {`
`2143`	`2143`	`/* we want exact results */`
`2144`	`2144`	`mpd_seterror(MPD(dec), MPD_Invalid_operation, &status);`
`2145`	`2145`	`}`