Merge pull request RustPython#1122 from palaviv/fix-exception-stack

windelbouwman · web-flow · commit bdd7fa88ec8d · 2019-07-09T20:24:04.000+02:00
Fix exception stack
diff --git a/tests/snippets/try_exceptions.py b/tests/snippets/try_exceptions.py
@@ -220,3 +220,21 @@ def y():
     raise NameError
 except NameError as ex:
     assert ex.__context__ == None
+
+
+try:
+    {}[1]
+except KeyError:
+    try:
+        raise RuntimeError()
+    except RuntimeError:
+        pass
+
+
+try:
+    try:
+        raise ZeroDivisionError
+    except ZeroDivisionError as ex:
+        raise NameError from ex
+except NameError as ex2:
+    pass
diff --git a/vm/src/frame.rs b/vm/src/frame.rs
@@ -752,7 +752,7 @@ impl Frame {
                     _ => vm.get_none(),
                 };
                 let exception = match argc {
-                    0 => match vm.pop_exception() {
+                    0 => match vm.current_exception() {
                         Some(exc) => exc,
                         None => {
                             return Err(vm.new_exception(
@@ -767,7 +767,7 @@ impl Frame {
                 };
                 let context = match argc {
                     0 => vm.get_none(), // We have already got the exception,
-                    _ => match vm.pop_exception() {
+                    _ => match vm.current_exception() {
                         Some(exc) => exc,
                         None => vm.get_none(),
                     },
@@ -891,7 +891,7 @@ impl Frame {
             bytecode::Instruction::PopException {} => {
                 let block = self.pop_block().unwrap(); // this asserts that the block is_some.
                 if let BlockType::ExceptHandler = block.typ {
-                    assert!(vm.pop_exception().is_some());
+                    vm.pop_exception().expect("Should have exception in stack");
                     Ok(None)
                 } else {
                     panic!("Block type must be ExceptHandler here.")
@@ -983,7 +983,7 @@ impl Frame {
                     }
                 }
                 BlockType::ExceptHandler => {
-                    vm.pop_exception();
+                    vm.pop_exception().expect("Should have exception in stack");
                 }
             }
         }
@@ -1009,7 +1009,7 @@ impl Frame {
                     }
                 },
                 BlockType::ExceptHandler => {
-                    vm.pop_exception();
+                    vm.pop_exception().expect("Should have exception in stack");
                 }
             }
 
@@ -1057,8 +1057,9 @@ impl Frame {
                     }
                 }
                 BlockType::Loop { .. } => {}
-                // Exception was already popped on Raised.
-                BlockType::ExceptHandler => {}
+                BlockType::ExceptHandler => {
+                    vm.pop_exception().expect("Should have exception in stack");
+                }
             }
         }
         Some(exc)
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
@@ -1014,6 +1014,10 @@ impl VirtualMachine {
     pub fn pop_exception(&self) -> Option<PyObjectRef> {
         self.exceptions.borrow_mut().pop()
     }
+
+    pub fn current_exception(&self) -> Option<PyObjectRef> {
+        self.exceptions.borrow().last().cloned()
+    }
 }
 
 impl Default for VirtualMachine {

Original file line number	Diff line number	Diff line change
`@@ -752,7 +752,7 @@ impl Frame {`
`752`	`752`	`_ => vm.get_none(),`
`753`	`753`	`};`
`754`	`754`	`let exception = match argc {`
`755`		`- 0 => match vm.pop_exception() {`
	`755`	`+ 0 => match vm.current_exception() {`
`756`	`756`	`Some(exc) => exc,`
`757`	`757`	`None => {`
`758`	`758`	`return Err(vm.new_exception(`
`@@ -767,7 +767,7 @@ impl Frame {`
`767`	`767`	`};`
`768`	`768`	`let context = match argc {`
`769`	`769`	`0 => vm.get_none(), // We have already got the exception,`
`770`		`- _ => match vm.pop_exception() {`
	`770`	`+ _ => match vm.current_exception() {`
`771`	`771`	`Some(exc) => exc,`
`772`	`772`	`None => vm.get_none(),`
`773`	`773`	`},`
`@@ -891,7 +891,7 @@ impl Frame {`
`891`	`891`	`bytecode::Instruction::PopException {} => {`
`892`	`892`	`let block = self.pop_block().unwrap(); // this asserts that the block is_some.`
`893`	`893`	`if let BlockType::ExceptHandler = block.typ {`
`894`		`- assert!(vm.pop_exception().is_some());`
	`894`	`+ vm.pop_exception().expect("Should have exception in stack");`
`895`	`895`	`Ok(None)`
`896`	`896`	`} else {`
`897`	`897`	`panic!("Block type must be ExceptHandler here.")`
`@@ -983,7 +983,7 @@ impl Frame {`
`983`	`983`	`}`
`984`	`984`	`}`
`985`	`985`	`BlockType::ExceptHandler => {`
`986`		`- vm.pop_exception();`
	`986`	`+ vm.pop_exception().expect("Should have exception in stack");`
`987`	`987`	`}`
`988`	`988`	`}`
`989`	`989`	`}`
`@@ -1009,7 +1009,7 @@ impl Frame {`
`1009`	`1009`	`}`
`1010`	`1010`	`},`
`1011`	`1011`	`BlockType::ExceptHandler => {`
`1012`		`- vm.pop_exception();`
	`1012`	`+ vm.pop_exception().expect("Should have exception in stack");`
`1013`	`1013`	`}`
`1014`	`1014`	`}`
`1015`	`1015`
`@@ -1057,8 +1057,9 @@ impl Frame {`
`1057`	`1057`	`}`
`1058`	`1058`	`}`
`1059`	`1059`	`BlockType::Loop { .. } => {}`
`1060`		`- // Exception was already popped on Raised.`
`1061`		`- BlockType::ExceptHandler => {}`
	`1060`	`+ BlockType::ExceptHandler => {`
	`1061`	`+ vm.pop_exception().expect("Should have exception in stack");`
	`1062`	`+ }`
`1062`	`1063`	`}`
`1063`	`1064`	`}`
`1064`	`1065`	`Some(exc)`
Original file line number	Diff line number	Diff line change
`@@ -1014,6 +1014,10 @@ impl VirtualMachine {`
`1014`	`1014`	`pub fn pop_exception(&self) -> Option<PyObjectRef> {`
`1015`	`1015`	`self.exceptions.borrow_mut().pop()`
`1016`	`1016`	`}`
	`1017`	`+`
	`1018`	`+ pub fn current_exception(&self) -> Option<PyObjectRef> {`
	`1019`	`+ self.exceptions.borrow().last().cloned()`
	`1020`	`+ }`
`1017`	`1021`	`}`
`1018`	`1022`
`1019`	`1023`	`impl Default for VirtualMachine {`