Add StackError and FormatError (#331)

msgpack/fallback.py

@@ -18,6 +18,16 @@ else:
     def dict_iteritems(d):
         return d.iteritems()
 
+if sys.version_info < (3, 5):
+    # Ugly hack...
+    RecursionError = RuntimeError
+
+    def _is_recursionerror(e):
+        return len(e.args) == 1 and isinstance(e.args[0], str) and \
+            e.args[0].startswith('maximum recursion depth exceeded')
+else:
+    def _is_recursionerror(e):
+        return True
 
 if hasattr(sys, 'pypy_version_info'):
     # cStringIO is slow on PyPy, StringIO is faster.  However: PyPy's own
@@ -52,7 +62,10 @@ else:
 from msgpack.exceptions import (
     BufferFull,
     OutOfData,
-    ExtraData)
+    ExtraData,
+    FormatError,
+    StackError,
+)
 
 from msgpack import ExtType
 
@@ -109,7 +122,12 @@ def unpackb(packed, **kwargs):
     """
     Unpack an object from `packed`.
 
-    Raises `ExtraData` when `packed` contains extra bytes.
+    Raises ``ExtraData`` when *packed* contains extra bytes.
+    Raises ``ValueError`` when *packed* is incomplete.
+    Raises ``FormatError`` when *packed* is not valid msgpack.
+    Raises ``StackError`` when *packed* contains too nested.
+    Other exceptions can be raised during unpacking.
+
     See :class:`Unpacker` for options.
     """
     unpacker = Unpacker(None, **kwargs)
@@ -117,7 +135,11 @@ def unpackb(packed, **kwargs):
     try:
         ret = unpacker._unpack()
     except OutOfData:
-        raise ValueError("Data is not enough.")
+        raise ValueError("Unpack failed: incomplete input")
+    except RecursionError as e:
+        if _is_recursionerror(e):
+            raise StackError
+        raise
     if unpacker._got_extradata():
         raise ExtraData(ret, unpacker._get_extradata())
     return ret
@@ -211,6 +233,12 @@ class Unpacker(object):
             unpacker.feed(buf)
             for o in unpacker:
                 process(o)
+
+    Raises ``ExtraData`` when *packed* contains extra bytes.
+    Raises ``OutOfData`` when *packed* is incomplete.
+    Raises ``FormatError`` when *packed* is not valid msgpack.
+    Raises ``StackError`` when *packed* contains too nested.
+    Other exceptions can be raised during unpacking.
     """
 
     def __init__(self, file_like=None, read_size=0, use_list=True, raw=True,
@@ -561,7 +589,7 @@ class Unpacker(object):
                 raise ValueError("%s exceeds max_map_len(%s)", n, self._max_map_len)
             typ = TYPE_MAP
         else:
-            raise ValueError("Unknown header: 0x%x" % b)
+            raise FormatError("Unknown header: 0x%x" % b)
         return typ, n, obj
 
     def _unpack(self, execute=EX_CONSTRUCT):
@@ -637,6 +665,8 @@ class Unpacker(object):
         except OutOfData:
             self._consume()
             raise StopIteration
+        except RecursionError:
+            raise StackError
 
     next = __next__
 
@@ -645,7 +675,10 @@ class Unpacker(object):
         self._consume()
 
     def unpack(self):
-        ret = self._unpack(EX_CONSTRUCT)
+        try:
+            ret = self._unpack(EX_CONSTRUCT)
+        except RecursionError:
+            raise StackError
         self._consume()
         return ret