[core] Change the token parsing part in prevision of different flags.

bonobo/execution/node.py

@@ -9,7 +9,7 @@ from bonobo.execution.base import LoopingExecutionContext
 from bonobo.structs.bags import Bag
 from bonobo.structs.inputs import Input
 from bonobo.structs.tokens import Token
-from bonobo.util import get_name, iserrorbag, isloopbackbag, isbag
+from bonobo.util import get_name, iserrorbag, isloopbackbag, isbag, istuple
 from bonobo.util.compat import deprecated_alias
 from bonobo.util.statistics import WithStatistics
 
@@ -137,12 +137,47 @@ class NodeExecutionContext(WithStatistics, LoopingExecutionContext):
             pass
 
 
-def _resolve(input_bag, output):
-    # NotModified means to send the input unmodified to output.
-    if output is NOT_MODIFIED:
-        return input_bag
+def isflag(param):
+    return isinstance(param, Token) and param in (NOT_MODIFIED,)
 
+
+def split_tokens(output):
+    """
+    Split an output into token tuple, real output tuple.
+
+    :param output:
+    :return: tuple, tuple
+    """
+    if isinstance(output, Token):
+        # just a flag
+        return (output,), ()
+
+    if not istuple(output):
+        # no flag
+        return (), (output,)
+
+    i = 0
+    while isflag(output[i]):
+        i += 1
+
+    return output[:i], output[i:]
+
+
+def _resolve(input_bag, output):
+    """
+    This function is key to how bonobo works (and internal, too). It transforms a pair of input/output into what is the
+    real output.
+
+    :param input_bag: Bag
+    :param output: mixed
+    :return: Bag
+    """
     if isbag(output):
         return output
 
-    return Bag(output)
+    tokens, output = split_tokens(output)
+
+    if len(tokens) == 1 and tokens[0] is NOT_MODIFIED:
+        return input_bag
+
+    return output if isbag(output) else Bag(output)

bonobo/nodes/io/json.py

@@ -53,7 +53,6 @@ class LdjsonReader(FileReader):
 
     def read(self, fs, file):
         for line in file:
-            print(line)
             yield self.loader(line)
 
 

tests/features/test_not_modified.py

@@ -0,0 +1,24 @@
+from bonobo.constants import NOT_MODIFIED
+from bonobo.util.testing import BufferingNodeExecutionContext
+
+
+def useless(*args, **kwargs):
+    return NOT_MODIFIED
+
+
+def test_not_modified():
+    input_messages = [
+        ('foo', 'bar'),
+        {'foo': 'bar'},
+        ('foo', {'bar': 'baz'}),
+        (),
+    ]
+
+    with BufferingNodeExecutionContext(useless) as context:
+        context.write_sync(*input_messages)
+
+    assert context.get_buffer() == input_messages
+
+
+
+