commit 0774e9b9f57197380c796d36353344cb95ed07bf
author Stefan Krah <skrah@bytereef.org> Thu Apr 05 15:21:58 2012 +0200
committer Stefan Krah <skrah@bytereef.org> Thu Apr 05 15:21:58 2012 +0200
tree 89d37955fb4526cf0f2a561b369788971746e93f
parent e7eee01f3697835d168f82357a6a97d7ca40d99a

Raise InvalidOperation if exponents of zeros are clamped during exact
conversion in the Decimal constructor. Exact here refers to the
representation and not to the value (clamping does not change the value).

Lib/test/test_decimal.py

diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 694b959..90f4015 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -4953,6 +4953,30 @@
         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,

Modules/_decimal/_decimal.c

diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index 32e336b..ad3c3df 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -1935,7 +1935,7 @@
     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 @@
         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);
     }

Modules/_decimal/tests/deccheck.py

diff --git a/Modules/_decimal/tests/deccheck.py b/Modules/_decimal/tests/deccheck.py
index aefbed6..c8da4d0 100644
--- a/Modules/_decimal/tests/deccheck.py
+++ b/Modules/_decimal/tests/deccheck.py
@@ -302,6 +302,7 @@
     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]: