Misc changes; exception chaining, PyBytesLike::into_buffer

vm/src/byteslike.rs

@@ -47,6 +47,12 @@ impl PyRwBytesLike {
     }
 }
 
+impl PyBytesLike {
+    pub fn into_buffer(self) -> BufferRef {
+        self.0
+    }
+}
+
 impl TryFromObject for PyBytesLike {
     fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
         let buffer = try_buffer_from_object(vm, &obj)?;
@@ -88,8 +94,8 @@ pub fn try_rw_bytes_like<R>(
         .ok_or_else(|| vm.new_type_error("buffer is not a read-write bytes-like object".to_owned()))
 }
 
-impl TryFromObject for PyRwBytesLike {
-    fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
+impl PyRwBytesLike {
+    pub fn new(vm: &VirtualMachine, obj: &PyObjectRef) -> PyResult<Self> {
         let buffer = try_buffer_from_object(vm, &obj)?;
         if !buffer.get_options().contiguous {
             Err(vm.new_type_error("non-contiguous buffer is not a bytes-like object".to_owned()))
@@ -99,6 +105,16 @@ impl TryFromObject for PyRwBytesLike {
             Ok(Self(buffer))
         }
     }
+
+    pub fn into_buffer(self) -> BufferRef {
+        self.0
+    }
+}
+
+impl TryFromObject for PyRwBytesLike {
+    fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
+        Self::new(vm, &obj)
+    }
 }
 
 impl<'a> BorrowValue<'a> for PyRwBytesLike {

vm/src/exceptions.rs

@@ -152,6 +152,17 @@ impl PyBaseException {
     }
 }
 
+pub fn chain<T>(e1: PyResult<()>, e2: PyResult<T>) -> PyResult<T> {
+    match (e1, e2) {
+        (Err(e1), Err(e)) => {
+            e.set_context(Some(e1));
+            Err(e)
+        }
+        (Err(e), Ok(_)) | (Ok(()), Err(e)) => Err(e),
+        (Ok(()), Ok(close_res)) => Ok(close_res),
+    }
+}
+
 /// Print exception chain by calling sys.excepthook
 pub fn print_exception(vm: &VirtualMachine, exc: PyBaseExceptionRef) {
     let write_fallback = |exc, errstr| {

vm/src/frame.rs

@@ -865,7 +865,15 @@ impl ExecutingFrame<'_> {
                         return Ok(None);
                     }
                 }
-                BlockType::FinallyHandler { .. } => {
+                BlockType::FinallyHandler {
+                    reason: finally_reason,
+                } => {
+                    if let Some(UnwindReason::Raising { exception }) = finally_reason {
+                        let finally_exc = exception;
+                        if let UnwindReason::Raising { exception } = &reason {
+                            exception.set_context(Some(finally_exc))
+                        }
+                    }
                     self.pop_block();
                 }
                 BlockType::ExceptHandler => {

vm/src/function.rs

@@ -187,25 +187,8 @@ impl FuncArgs {
     /// during the conversion will halt the binding and return the error.
     pub fn bind<T: FromArgs>(mut self, vm: &VirtualMachine) -> PyResult<T> {
         let given_args = self.args.len();
-        let bound = T::from_args(vm, &mut self).map_err(|e| match e {
-            ArgumentError::TooFewArgs => vm.new_type_error(format!(
-                "Expected at least {} arguments ({} given)",
-                T::arity().start(),
-                given_args,
-            )),
-            ArgumentError::TooManyArgs => vm.new_type_error(format!(
-                "Expected at most {} arguments ({} given)",
-                T::arity().end(),
-                given_args,
-            )),
-            ArgumentError::InvalidKeywordArgument(name) => {
-                vm.new_type_error(format!("{} is an invalid keyword argument", name))
-            }
-            ArgumentError::RequiredKeywordArgument(name) => {
-                vm.new_type_error(format!("Required keyqord only argument {}", name))
-            }
-            ArgumentError::Exception(ex) => ex,
-        })?;
+        let bound = T::from_args(vm, &mut self)
+            .map_err(|e| e.into_exception(T::arity(), given_args, vm))?;
 
         if !self.args.is_empty() {
             Err(vm.new_type_error(format!(
@@ -243,6 +226,35 @@ impl From<PyBaseExceptionRef> for ArgumentError {
     }
 }
 
+impl ArgumentError {
+    fn into_exception(
+        self,
+        arity: RangeInclusive<usize>,
+        num_given: usize,
+        vm: &VirtualMachine,
+    ) -> PyBaseExceptionRef {
+        match self {
+            ArgumentError::TooFewArgs => vm.new_type_error(format!(
+                "Expected at least {} arguments ({} given)",
+                arity.start(),
+                num_given
+            )),
+            ArgumentError::TooManyArgs => vm.new_type_error(format!(
+                "Expected at most {} arguments ({} given)",
+                arity.end(),
+                num_given
+            )),
+            ArgumentError::InvalidKeywordArgument(name) => {
+                vm.new_type_error(format!("{} is an invalid keyword argument", name))
+            }
+            ArgumentError::RequiredKeywordArgument(name) => {
+                vm.new_type_error(format!("Required keyqord only argument {}", name))
+            }
+            ArgumentError::Exception(ex) => ex,
+        }
+    }
+}
+
 /// Implemented by any type that can be accepted as a parameter to a built-in
 /// function.
 ///
@@ -439,7 +451,7 @@ impl OptionalArg<PyObjectRef> {
     }
 }
 
-pub type OptionalOption<T> = OptionalArg<Option<T>>;
+pub type OptionalOption<T = PyObjectRef> = OptionalArg<Option<T>>;
 
 impl<T> OptionalOption<T> {
     #[inline]