White space U+000C FORM FEED incorrectly removed by Spyder text editor

The U+000C (FORM FEED) character is valid white space in text, including Python source code.

What steps will reproduce the problem?

• Create a text file foo.txt containing several lines of text, including one line containing only a U+000C character.

• Open the file foo.txt in Spyder.

  Spyder will raise a modal dialogue “foo.txt contains mixed end-of-line characters. Spyder will fix this automatically.”

• The U+000C characters have been removed.

What is the expected output? What do you see instead?

Actual: The text is altered, by removing the valid characters.

Expected: the U+000C character should be treated as valid vertical white space, no message, and left unchanged.

The non-printable U+000C is typically shown in text editors by a visible glyph (e.g. “^L” or “↡”) in a different colour.

Please provide any additional information below

“The form feed character is sometimes used in plain text files of source code as a delimiter for a page break, or as marker for sections of code.” — https://en.wikipedia.org/wiki/Page_break#Form_feed

“A logical line that contains only spaces, tabs, formfeeds and possibly a comment, is ignored” — https://docs.python.org/3/reference/lexical_analysis.html#blank-lines

Version and main components

• Spyder Version: 3.2.4
• Python Version: 3.6.4
• Qt Versions: 5.9.2, PyQt5 5.9.2 on Linux

Dependencies

pyflakes >=0.6.0 :  1.6.0 (OK)
pycodestyle >=2.3:  2.3.1 (OK)
pygments >=2.0   :  2.2.0 (OK)
pandas >=0.13.1  :  0.20.3 (OK)
numpy >=1.7      :  1.13.3 (OK)
sphinx >=0.6.6   :  1.6.5 (OK)
rope >=0.9.4     :  0.10.5 (OK)
jedi >=0.9.0     :  0.11.0 (OK)
psutil >=0.3     :  5.4.2 (OK)
nbconvert >=4.0  :  5.3.1 (OK)
sympy >=0.7.3    :  1.1.1 (OK)
cython >=0.21    :  None (NOK)
qtconsole >=4.2.0:  4.3.1 (OK)
IPython >=4.0    :  6.2.1 (OK)
pylint >=0.25    :  1.7.4 (OK)

[ccordoba12]

I don’t maintain code at GitHub (because Git is a fully distributed version control system), and I am pretty sure GitHub does not work for pull requests from repositories elsewhere.

Sorry, we’re pretty swamped and don’t have time to do your job. If you want your work integrated in Spyder, please open a pull request like everybody else.

[jitseniesen]

In my opinion this is a bug. A formfeed character is not an end-of-line character. However, it is a very low priority issue for me because I don’t recall seeing formfeeds in Python source files.

I thought that closing as wontfix means we (as developers) don’t want to fix it. If we would consider pull requests, I think the bug should be kept open and perhaps given an appropriate label as wishlist (which does not exist) or help wanted (which does exist but is perhaps not so clear).