Merge banana-unsupported-type-exception-7663

Author: wolfgang61, exarkun Reviewer: exarkun Fixes: twisted#7663 Change Banana's unsupported type exception message to include the type of the unsupported object. git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/trunk@43213 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
daodaoliang · Oct 5, 2014 · fbad806 · fbad806
1 parent 3a0f978
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diff --git a/docs/core/specifications/banana.rst b/docs/core/specifications/banana.rst
@@ -14,16 +14,10 @@ Banana Protocol Specifications
 Introduction
 ------------
 
-
-
-
 Banana is an efficient, extendable protocol for sending and receiving s-expressions.
-A s-expression in this context is a list composed of byte strings, integers, 
-large integers, floats and/or s-expressions.
-
-
-
-
+A s-expression in this context is a list composed of bytes, integers, large integers, floats and/or s-expressions.
+Unicode is not supported (but can be encoded to and decoded from bytes on the way into and out of Banana).
+Unsupported types must be converted into a supported type before sending them with Banana.
 
 
 Banana Encodings

diff --git a/twisted/spread/banana.py b/twisted/spread/banana.py
@@ -17,6 +17,7 @@
 from twisted.internet import protocol
 from twisted.persisted import styles
 from twisted.python import log
+from twisted.python.reflect import fullyQualifiedName
 
 class BananaError(Exception):
     pass
@@ -282,6 +283,16 @@ def __init__(self, isClient=1):
         self.isClient = isClient
 
     def sendEncoded(self, obj):
+        """
+        Send the encoded representation of the given object:
+
+        @param obj: An object to encode and send.
+
+        @raise BananaError: If the given object is not an instance of one of
+            the types supported by Banana.
+
+        @return: C{None}
+        """
         io = cStringIO.StringIO()
         self._encode(obj, io.write)
         value = io.getvalue()
@@ -329,7 +340,8 @@ def _encode(self, obj, write):
                 write(STRING)
                 write(obj)
         else:
-            raise BananaError("could not send object: %r" % (obj,))
+            raise BananaError("Banana cannot send {0} objects: {1!r}".format(
+                fullyQualifiedName(type(obj)), obj))
 
 
 # For use from the interactive interpreter

diff --git a/twisted/test/test_banana.py b/twisted/test/test_banana.py
@@ -45,6 +45,51 @@ def testString(self):
         self.enc.dataReceived(self.io.getvalue())
         assert self.result == 'hello'
 
+
+    def test_unsupportedUnicode(self):
+        """
+        Banana does not support unicode.  ``Banana.sendEncoded`` raises
+        ``BananaError`` if called with an instance of ``unicode``.
+        """
+        self._unsupportedTypeTest(u"hello", "__builtin__.unicode")
+
+
+    def test_unsupportedBuiltinType(self):
+        """
+        Banana does not support arbitrary builtin types like L{type}.
+        L{banana.Banana.sendEncoded} raises L{banana.BananaError} if called
+        with an instance of L{type}.
+        """
+        # type is an instance of type
+        self._unsupportedTypeTest(type, "__builtin__.type")
+
+
+    def test_unsupportedUserType(self):
+        """
+        Banana does not support arbitrary user-defined types (such as those
+        defined with the ``class`` statement).  ``Banana.sendEncoded`` raises
+        ``BananaError`` if called with an instance of such a type.
+        """
+        self._unsupportedTypeTest(MathTestCase(), __name__ + ".MathTestCase")
+
+
+    def _unsupportedTypeTest(self, obj, name):
+        """
+        Assert that L{banana.Banana.sendEncoded} raises L{banana.BananaError}
+        if called with the given object.
+
+        @param obj: Some object that Banana does not support.
+        @param name: The name of the type of the object.
+
+        @raise: The failure exception is raised if L{Banana.sendEncoded} does
+            not raise L{banana.BananaError} or if the message associated with the
+            exception is not formatted to include the type of the unsupported
+            object.
+        """
+        exc = self.assertRaises(banana.BananaError, self.enc.sendEncoded, obj)
+        self.assertIn("Banana cannot send {0} objects".format(name), str(exc))
+
+
     def test_int(self):
         """
         A positive integer less than 2 ** 32 should round-trip through

diff --git a/twisted/topfiles/7663.feature b/twisted/topfiles/7663.feature
@@ -0,0 +1 @@
+twisted.spread.banana.Banana.sendEncoded() now raises a more informative error message if the user tries to encode objects of unsupported type.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		twisted.spread.banana.Banana.sendEncoded() now raises a more informative error message if the user tries to encode objects of unsupported type.