Raise SyntaxError for illegal jumps

Author: snoack

goto.py

@@ -89,15 +89,16 @@ def _patch_code(code):
 		try:
 			label_pos, label_stack = labels[arg]
 		except KeyError:
-			continue
+			raise SyntaxError('Unknown label %r' % code.co_names[arg])
 
 		label_depth = len(label_stack)
 		if goto_stack[:label_depth] != label_stack:
-			continue
+			raise SyntaxError('Jumps into different blocks are not allowed')
 
 		depth_delta = len(goto_stack) - label_depth
-		if depth_delta > _STRUCT_ATTR_LOOKUP.size - _STRUCT_OP_WITH_ARG.size:
-			continue
+		max_depth_delta = _STRUCT_ATTR_LOOKUP.size - _STRUCT_OP_WITH_ARG.size
+		if depth_delta > max_depth_delta:
+			raise SyntaxError('Jumps out of more than %d nested blocks are not allowed' % max_depth_delta)
 
 		_inject_ops(buf, goto_pos, 'NOP', _STRUCT_ATTR_LOOKUP.size)
 		_inject_ops(buf, goto_pos, 'POP_BLOCK', depth_delta)

test_goto.py

@@ -39,13 +39,12 @@ def func():
 	assert func() == 0
 
 def test_jump_into_loop():
-	@with_goto
 	def func():
 		for i in range(10):
 			label .loop
 		goto .loop
 
-	pytest.raises(NameError, func)
+	pytest.raises(SyntaxError, with_goto, func)
 
 def test_jump_out_of_nested_4_loops():
 	@with_goto
@@ -61,7 +60,6 @@ def func():
 	assert func() == (0, 0, 0, 0)
 
 def test_jump_out_of_nested_5_loops():
-	@with_goto
 	def func():
 		for i in range(2):
 			for j in range(2):
@@ -72,18 +70,17 @@ def func():
 		label .end
 		return (i, j, k, m, n)
 
-	pytest.raises(NameError, func)
+	pytest.raises(SyntaxError, with_goto, func)
 
 def test_jump_across_loops():
-	@with_goto
 	def func():
 		for i in range(10):
 			goto .other_loop
 
 		for i in range(10):
 			label .other_loop
 
-	pytest.raises(NameError, func)
+	pytest.raises(SyntaxError, with_goto, func)
 
 def test_jump_out_of_try_block():
 	@with_goto
@@ -101,12 +98,17 @@ def func():
 	assert func() == None
 
 def test_jump_into_try_block():
-	@with_goto
 	def func():
 		try:
 			label .block
 		except:
 			pass
 		goto .block
 
-	pytest.raises(NameError, func)
+	pytest.raises(SyntaxError, with_goto, func)
+
+def test_jump_to_unkown_label():
+	def func():
+		goto .unknown
+
+	pytest.raises(SyntaxError, with_goto, func)