fix floordiv and divmod by zero for ints and floats

Author: silmeth

tests/snippets/builtin_divmod.py

@@ -1,3 +1,17 @@
 assert divmod(11, 3) == (3, 2)
 assert divmod(8,11) == (0, 8)
 assert divmod(0.873, 0.252) == (3.0, 0.11699999999999999)
+
+try:
+    divmod(5, 0)
+except ZeroDivisionError:
+    pass
+else:
+    assert False, "Expected divmod by zero to throw ZeroDivisionError"
+
+try:
+    divmod(5.0, 0.0)
+except ZeroDivisionError:
+    pass
+else:
+    assert False, "Expected divmod by zero to throw ZeroDivisionError"

tests/snippets/division_by_zero.py

@@ -26,6 +26,27 @@
 else:
     assert False, 'Expected ZeroDivisionError'
 
+try:
+    5 // 0
+except ZeroDivisionError:
+    pass
+else:
+    assert False, 'Expected ZeroDivisionError'
+
+try:
+    5.3 // (-0.0)
+except ZeroDivisionError:
+    pass
+else:
+    assert False, 'Expected ZeroDivisionError'
+
+try:
+    divmod(5, 0)
+except ZeroDivisionError:
+    pass
+else:
+    assert False, 'Expected ZeroDivisionError'
+
 try:
     raise ZeroDivisionError('Is an ArithmeticError subclass?')
 except ArithmeticError:

vm/src/obj/objfloat.rs

@@ -172,9 +172,9 @@ fn float_divmod(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     let args = PyFuncArgs::new(vec![i.clone(), i2.clone()], vec![]);
     if objtype::isinstance(i2, &vm.ctx.float_type()) || objtype::isinstance(i2, &vm.ctx.int_type())
     {
-        let r1 = float_floordiv(vm, args.clone());
-        let r2 = float_mod(vm, args.clone());
-        Ok(vm.ctx.new_tuple(vec![r1.unwrap(), r2.unwrap()]))
+        let r1 = float_floordiv(vm, args.clone())?;
+        let r2 = float_mod(vm, args.clone())?;
+        Ok(vm.ctx.new_tuple(vec![r1, r2]))
     } else {
         Err(vm.new_type_error(format!(
             "Cannot divmod power {} and {}",
@@ -190,18 +190,26 @@ fn float_floordiv(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
         args,
         required = [(i, Some(vm.ctx.float_type())), (i2, None)]
     );
-    if objtype::isinstance(i2, &vm.ctx.float_type()) {
-        Ok(vm.ctx.new_float((get_value(i) / get_value(i2)).floor()))
-    } else if objtype::isinstance(i2, &vm.ctx.int_type()) {
-        Ok(vm
-            .ctx
-            .new_float((get_value(i) / objint::get_value(i2).to_f64().unwrap()).floor()))
+
+    let v1 = get_value(i);
+    let v2 = if objtype::isinstance(i2, &vm.ctx.float_type) {
+        get_value(i2)
+    } else if objtype::isinstance(i2, &vm.ctx.int_type) {
+        objint::get_value(i2)
+            .to_f64()
+            .ok_or_else(|| vm.new_overflow_error("int too large to convert to float".to_string()))?
     } else {
-        Err(vm.new_type_error(format!(
+        return Err(vm.new_type_error(format!(
             "Cannot floordiv {} and {}",
             i.borrow(),
             i2.borrow()
-        )))
+        )));
+    };
+
+    if v2 != 0.0 {
+        Ok(vm.ctx.new_float((v1 / v2).floor()))
+    } else {
+        Err(vm.new_zero_division_error("float floordiv by zero".to_string()))
     }
 }
 
@@ -229,14 +237,22 @@ fn float_mod(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
         args,
         required = [(i, Some(vm.ctx.float_type())), (i2, None)]
     );
-    if objtype::isinstance(i2, &vm.ctx.float_type()) {
-        Ok(vm.ctx.new_float(get_value(i) % get_value(i2)))
-    } else if objtype::isinstance(i2, &vm.ctx.int_type()) {
-        Ok(vm
-            .ctx
-            .new_float(get_value(i) % objint::get_value(i2).to_f64().unwrap()))
+
+    let v1 = get_value(i);
+    let v2 = if objtype::isinstance(i2, &vm.ctx.float_type) {
+        get_value(i2)
+    } else if objtype::isinstance(i2, &vm.ctx.int_type) {
+        objint::get_value(i2)
+            .to_f64()
+            .ok_or_else(|| vm.new_overflow_error("int too large to convert to float".to_string()))?
+    } else {
+        return Err(vm.new_type_error(format!("Cannot mod {} and {}", i.borrow(), i2.borrow())));
+    };
+
+    if v2 != 0.0 {
+        Ok(vm.ctx.new_float(v1 % v2))
     } else {
-        Err(vm.new_type_error(format!("Cannot mod {} and {}", i.borrow(), i2.borrow())))
+        Err(vm.new_zero_division_error("float mod by zero".to_string()))
     }
 }
 
@@ -272,15 +288,22 @@ fn float_truediv(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
         args,
         required = [(i, Some(vm.ctx.float_type())), (i2, None)]
     );
+
     let v1 = get_value(i);
-    if objtype::isinstance(i2, &vm.ctx.float_type) {
-        Ok(vm.ctx.new_float(v1 / get_value(i2)))
+    let v2 = if objtype::isinstance(i2, &vm.ctx.float_type) {
+        get_value(i2)
     } else if objtype::isinstance(i2, &vm.ctx.int_type) {
-        Ok(vm
-            .ctx
-            .new_float(v1 / objint::get_value(i2).to_f64().unwrap()))
+        objint::get_value(i2)
+            .to_f64()
+            .ok_or_else(|| vm.new_overflow_error("int too large to convert to float".to_string()))?
+    } else {
+        return Err(vm.new_type_error(format!("Cannot divide {} and {}", i.borrow(), i2.borrow())));
+    };
+
+    if v2 != 0.0 {
+        Ok(vm.ctx.new_float(v1 / v2))
     } else {
-        Err(vm.new_type_error(format!("Cannot divide {} and {}", i.borrow(), i2.borrow())))
+        Err(vm.new_zero_division_error("float division by zero".to_string()))
     }
 }
 

vm/src/obj/objint.rs

@@ -8,6 +8,7 @@ use super::objfloat;
 use super::objstr;
 use super::objtype;
 use num_bigint::{BigInt, ToBigInt};
+use num_integer::Integer;
 use num_traits::{Pow, Signed, ToPrimitive, Zero};
 use std::hash::{Hash, Hasher};
 
@@ -289,7 +290,13 @@ fn int_floordiv(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
         required = [(i, Some(vm.ctx.int_type())), (i2, None)]
     );
     if objtype::isinstance(i2, &vm.ctx.int_type()) {
-        Ok(vm.ctx.new_int(get_value(i) / get_value(i2)))
+        let (v1, v2) = (get_value(i), get_value(i2));
+
+        if v2 != BigInt::zero() {
+            Ok(vm.ctx.new_int(v1 / v2))
+        } else {
+            Err(vm.new_zero_division_error("integer floordiv by zero".to_string()))
+        }
     } else {
         Err(vm.new_type_error(format!(
             "Cannot floordiv {} and {}",
@@ -462,11 +469,20 @@ fn int_divmod(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
         args,
         required = [(i, Some(vm.ctx.int_type())), (i2, None)]
     );
-    let args = PyFuncArgs::new(vec![i.clone(), i2.clone()], vec![]);
+
     if objtype::isinstance(i2, &vm.ctx.int_type()) {
-        let r1 = int_floordiv(vm, args.clone());
-        let r2 = int_mod(vm, args.clone());
-        Ok(vm.ctx.new_tuple(vec![r1.unwrap(), r2.unwrap()]))
+        let v1 = get_value(i);
+        let v2 = get_value(i2);
+
+        if v2 != BigInt::zero() {
+            let (r1, r2) = v1.div_rem(&v2);
+
+            Ok(vm
+                .ctx
+                .new_tuple(vec![vm.ctx.new_int(r1), vm.ctx.new_int(r2)]))
+        } else {
+            Err(vm.new_zero_division_error("integer divmod by zero".to_string()))
+        }
     } else {
         Err(vm.new_type_error(format!(
             "Cannot divmod power {} and {}",