[GR-24025] [GR-23328] pow() with 2 arguments (or None as third) should call __pow__ with 2 args

PullRequest: graalpython/1035

Author: timfel

graalpython/com.oracle.graal.python.test/src/tests/test_binary_arithmetic.py

@@ -299,6 +299,19 @@ def test_pow():
     # (0xffffffffffffffff >> 63) is used to produce a non-narrowed int
     assert 2**(0xffffffffffffffff >> 63) == 2
 
+    # test that two-argument pow functions work
+    class M:
+        def __pow__(self, power):
+            return (type(self), power)
+    assert pow(M(), 2) == (M, 2)
+    assert pow(M(), 2, None) == (M, 2)
+    try:
+        pow(M(), 2, 3)
+    except TypeError:
+        assert True
+    else:
+        assert False
+
     if sys.version_info.minor >= 8:
         # for some reason this hangs CPython on the CI even if it's just parsed
         from pow_tests import test_pow

graalpython/com.oracle.graal.python.test/src/tests/unittest_tags/test_pow.txt

@@ -1,4 +1,7 @@
 *graalpython.lib-python.3.test.test_pow.PowTest.test_bug643260
 *graalpython.lib-python.3.test.test_pow.PowTest.test_bug705231
+*graalpython.lib-python.3.test.test_pow.PowTest.test_negative_exponent
 *graalpython.lib-python.3.test.test_pow.PowTest.test_other
 *graalpython.lib-python.3.test.test_pow.PowTest.test_powfloat
+*graalpython.lib-python.3.test.test_pow.PowTest.test_powint
+

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinFunctions.java

@@ -1754,11 +1754,24 @@ private int getDebuggerSessionCount() {
 
     @Builtin(name = POW, minNumOfPositionalArgs = 2, parameterNames = {"base", "exp", "mod"})
     @GenerateNodeFactory
-    public abstract static class PowNode extends PythonBuiltinNode {
-        @Child private LookupAndCallTernaryNode powNode = TernaryArithmetic.Pow.create();
+    public abstract static class PowNode extends PythonTernaryBuiltinNode {
+        static LookupAndCallBinaryNode binaryPow() {
+            return BinaryArithmetic.Pow.create();
+        }
+
+        static LookupAndCallTernaryNode ternaryPow() {
+            return TernaryArithmetic.Pow.create();
+        }
 
         @Specialization
-        Object doIt(VirtualFrame frame, Object x, Object y, Object z) {
+        Object binary(VirtualFrame frame, Object x, Object y, @SuppressWarnings("unused") PNone z,
+                        @Cached("binaryPow()") LookupAndCallBinaryNode powNode) {
+            return powNode.executeObject(frame, x, y);
+        }
+
+        @Specialization(guards = "!isPNone(z)")
+        Object ternary(VirtualFrame frame, Object x, Object y, Object z,
+                        @Cached("ternaryPow()") LookupAndCallTernaryNode powNode) {
             return powNode.execute(frame, x, y, z);
         }
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/ints/IntBuiltins.java

@@ -577,7 +577,11 @@ static BigInteger op(BigInteger a, BigInteger b) {
 
         @TruffleBoundary
         static BigInteger opNeg(BigInteger a, BigInteger b) {
-            if (a.equals(BigInteger.ZERO)) {
+            if (a.signum() == 0) {
+                return BigInteger.ZERO;
+            }
+            BigInteger mod = a.mod(b.negate());
+            if (mod.signum() == 0) {
                 return BigInteger.ZERO;
             }
             return a.mod(b.negate()).subtract(b.negate());
@@ -705,17 +709,22 @@ PInt doLLPos(long left, long right, @SuppressWarnings("unused") PNone none) {
         }
 
         @Specialization(guards = "right < 0")
-        static double doLLNeg(long left, long right, @SuppressWarnings("unused") PNone none) {
+        double doLLNeg(long left, long right, @SuppressWarnings("unused") PNone none,
+                        @Shared("leftIsZero") @Cached ConditionProfile leftIsZero) {
+            if (leftIsZero.profile(left == 0)) {
+                throw raise(PythonBuiltinClassType.ZeroDivisionError, ErrorMessages.POW_ZERO_CANNOT_RAISE_TO_NEGATIVE_POWER);
+            }
             return Math.pow(left, right);
         }
 
         @Specialization(rewriteOn = ArithmeticException.class)
-        static Object doLPNarrow(long left, PInt right, @SuppressWarnings("unused") PNone none) {
+        Object doLPNarrow(long left, PInt right, @SuppressWarnings("unused") PNone none,
+                        @Shared("leftIsZero") @Cached ConditionProfile leftIsZero) {
             long lright = right.longValueExact();
             if (lright >= 0) {
                 return doLLFast(left, lright, none);
             }
-            return doLLNeg(left, lright, none);
+            return doLLNeg(left, lright, none, leftIsZero);
         }
 
         @Specialization(replaces = "doLPNarrow")
@@ -739,7 +748,11 @@ PInt doPLPos(PInt left, long right, @SuppressWarnings("unused") PNone none) {
         }
 
         @Specialization(guards = "right < 0")
-        double doPLNeg(PInt left, long right, @SuppressWarnings("unused") PNone none) {
+        double doPLNeg(PInt left, long right, @SuppressWarnings("unused") PNone none,
+                        @Shared("leftIsZero") @Cached ConditionProfile leftIsZero) {
+            if (leftIsZero.profile(left.isZero())) {
+                throw raise(PythonBuiltinClassType.ZeroDivisionError, ErrorMessages.POW_ZERO_CANNOT_RAISE_TO_NEGATIVE_POWER);
+            }
             return TrueDivNode.op(BigInteger.ONE, op(left.getValue(), -right), getRaiseNode());
         }
 
@@ -886,6 +899,8 @@ private Object op(BigInteger left, BigInteger right) {
                     // we'll raise unless left is one of the shortcut values
                     return op(left, Long.MAX_VALUE);
                 }
+            } else if (left.signum() == 0) {
+                throw raise(PythonBuiltinClassType.ZeroDivisionError, ErrorMessages.POW_ZERO_CANNOT_RAISE_TO_NEGATIVE_POWER);
             } else {
                 try {
                     return Math.pow(left.longValueExact(), right.longValueExact());