Merge pull request #4088 from jdfreder/coalfix

nbconvert: Fix coalescestreams line with incorrect nesting causing strange behavior

closes  #4015

IPython/nbconvert/preprocessors/coalescestreams.py

@@ -1,75 +1,75
 """Module that allows latex output notebooks to be conditioned before
 they are converted.  Exposes a decorator (@cell_preprocessor) in
 addition to the coalesce_streams pre-proccessor.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 def cell_preprocessor(function):
     """
     Wrap a function to be executed on all cells of a notebook
     
     Wrapped Parameters
     ----------
     cell : NotebookNode cell
         Notebook cell being processed
     resources : dictionary
         Additional resources used in the conversion process.  Allows
         preprocessors to pass variables into the Jinja engine.
     index : int
         Index of the cell being processed
     """
     
     def wrappedfunc(nb, resources):
         for worksheet in nb.worksheets :
             for index, cell in enumerate(worksheet.cells):
                 worksheet.cells[index], resources = function(cell, resources, index)
         return nb, resources
     return wrappedfunc
 
 
 @cell_preprocessor
 def coalesce_streams(cell, resources, index):
     """
     Merge consecutive sequences of stream output into single stream
     to prevent extra newlines inserted at flush calls
     
     Parameters
     ----------
     cell : NotebookNode cell
         Notebook cell being processed
     resources : dictionary
         Additional resources used in the conversion process.  Allows
         transformers to pass variables into the Jinja engine.
     index : int
         Index of the cell being processed
     """
     
     outputs = cell.get('outputs', [])
     if not outputs:
         return cell, resources
     
     last = outputs[0]
     new_outputs = [last]
     
     for output in outputs[1:]:
         if (output.output_type == 'stream' and
             last.output_type == 'stream' and
             last.stream == output.stream
         ):
             last.text += output.text
         else:
             new_outputs.append(output)
-        last = output
+            last = output
 
     cell.outputs = new_outputs
     return cell, resources

IPython/nbconvert/preprocessors/tests/test_coalescestreams.py

@@ -1,38 +1,60
 """
 Module with tests for the coalescestreams preprocessor
 """
 
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
+from IPython.nbformat import current as nbformat
+
 from .base import PreprocessorTestsBase
 from ..coalescestreams import coalesce_streams
 
 
 #-----------------------------------------------------------------------------
 # Class
 #-----------------------------------------------------------------------------
 
 class TestCoalesceStreams(PreprocessorTestsBase):
     """Contains test functions for coalescestreams.py"""
 
     def test_coalesce_streams(self):
         """coalesce_streams preprocessor output test"""
         nb = self.build_notebook()
         res = self.build_resources()
         nb, res = coalesce_streams(nb, res)
         outputs = nb.worksheets[0].cells[0].outputs
         self.assertEqual(outputs[0].text, "a")
         self.assertEqual(outputs[1].output_type, "text")
         self.assertEqual(outputs[2].text, "cd")
         self.assertEqual(outputs[3].text, "ef")
-    
+
+
+    def test_coalesce_sequenced_streams(self):
+        """Can the coalesce streams preprocessor merge a sequence of streams?"""
+
+        outputs = [nbformat.new_output(output_type="stream", stream="stdout", output_text="0"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="1"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="2"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="3"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="4"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="5"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="6"),
+                   nbformat.new_output(output_type="stream", stream="stdout", output_text="7")]
+        cells=[nbformat.new_code_cell(input="# None", prompt_number=1,outputs=outputs)]
+        worksheets = [nbformat.new_worksheet(name="worksheet1", cells=cells)]
+
+        nb = nbformat.new_notebook(name="notebook1", worksheets=worksheets)
+        res = self.build_resources()
+        nb, res = coalesce_streams(nb, res)
+        outputs = nb.worksheets[0].cells[0].outputs
+        self.assertEqual(outputs[0].text, u'01234567')