Fix bug where tab-completion with very long filenames would crash the qt console.

Any time tab completion was activated with a filename in the path
longer than the width of the window, the console would crash.

IPython/utils/tests/test_text.py

@@ -26,5 +26,19 b' from IPython.utils import text'
 #-----------------------------------------------------------------------------
 
 def test_columnize():
-    """Test columnize with very long inputs"""
-    text.columnize(['a'*180, 'b'*180])
+    """Basic columnize tests."""
+    size = 5
+    items = [l*size for l in 'abc']
+    out = text.columnize(items, displaywidth=80)
+    nt.assert_equals(out, 'aaaaa  bbbbb  ccccc\n')
+    out = text.columnize(items, displaywidth=10)
+    nt.assert_equals(out, 'aaaaa  ccccc\nbbbbb\n')
+
+
+def test_columnize_long():
+    """Test columnize with inputs longer than the display window"""
+    text.columnize(['a'*81, 'b'*81], displaywidth=80)
+    size = 11
+    items = [l*size for l in 'abc']
+    out = text.columnize(items, displaywidth=size-1)
+    nt.assert_equals(out, '\n'.join(items+['']))

IPython/utils/text.py

@@ -639,6 +639,13 b" def columnize(items, separator=' ', displaywidth=80):"
     elif size == 1:
         return '%s\n' % items[0]
 
+    # Special case: if any item is longer than the maximum width, there's no
+    # point in triggering the logic below...
+    item_len = map(len, items) # save these, we can reuse them below
+    longest = max(item_len)
+    if longest >= displaywidth:
+        return '\n'.join(items+[''])
+
     # Try every row count from 1 upwards
     array_index = lambda nrows, row, col: nrows*col + row
     for nrows in range(1, size):
@@ -651,8 +658,8 b" def columnize(items, separator=' ', displaywidth=80):"
             for row in range(nrows):
                 i = array_index(nrows, row, col)
                 if i >= size: break
-                x = items[i]
-                colwidth = max(colwidth, len(x))
+                x, len_x = items[i], item_len[i]
+                colwidth = max(colwidth, len_x)
             colwidths.append(colwidth)
             totwidth += colwidth + len(separator)
             if totwidth > displaywidth: