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Black formatting leaves an extra line at the end of the file #1877

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Black formatting leaves an extra line at the end of the file#1877
Labels
area-editor-*User-facing catch-allarea-formattingbugIssue identified by VS Code Team member as probable bug

Description

@Tinche
Tin Tvrtković (Tinche)
opened on Jun 6, 2018

Environment data

  • VS Code version: 1.23.1
  • Extension version (available under the Extensions sidebar): 2018.5.0
  • OS and version: macOs High Sierra
  • Python version (& distribution if applicable, e.g. Anaconda): CPython 3.6.5
  • Type of virtual environment used (N/A | venv | virtualenv | conda | ...): venv
  • Relevant/affected Python packages and their versions: black-18.6b1

Actual behavior

Formatting using black leaves two empty lines at the end of the file, if the file has more than 1 empty line already.

Expected behavior

Formatting should leave just one line, and this is what happens when I run black manually from the terminal.

Steps to reproduce:

  1. Open Python file
  2. Insert 10 empty lines at the end
  3. Activate "Format document" with black set as the formatter

Logs

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

##########Linting Output - flake8##########
20,1,W,W391:blank line at end of file

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

Activity

  1. ImageBrett Cannon (brettcannon)
    added
    bugIssue identified by VS Code Team member as probable bug
    needs verification
    area-formatting
    needs PR
    and removed
    needs verification
    on Jun 6, 2018

  2. brettcannon commented on Jun 6, 2018

    @brettcannon
    Brett Cannon (brettcannon)
    on Jun 6, 2018
    Member

    I can reproduce and the expected behaviour that Tin Tvrtković (@Tinche) found and I can verify that using black --diff does what is expected:

    --- tpn\tpn\tests\test_npm.py   2018-06-06 22:04:15.383923 +0000
+++ tpn\tpn\tests\test_npm.py   2018-06-06 22:05:29.227218 +0000
@@ -71,16 +71,5 @@

 def test_find_license():
     # XXX
     pass

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  3. ImageBrett Cannon (brettcannon)
    added this to the June 2018 milestone on Jun 12, 2018
  4. ImageDon Jayamanne (DonJayamanne)
    self-assigned this
    on Jun 13, 2018

  5. brettcannon commented on Jun 13, 2018

    @brettcannon
    Brett Cannon (brettcannon)
    on Jun 13, 2018
    Member

    Don Jayamanne (@DonJayamanne) so when I tested this I added the blank lines, we just weren't stripping them out. So I don't think it's a case of adding as much as not removing.

  6. ImageDon Jayamanne (DonJayamanne)
    modified the milestones: June 2018, July 2018 on Jun 13, 2018

  7. DonJayamanne commented on Jun 13, 2018

    @DonJayamanne
    Don Jayamanne (DonJayamanne)
    on Jun 13, 2018

    I think its best to use an npm package (e.g. https://www.npmjs.com/package/diff) rather than parsing diff patches manually.
    Moving to July

    This will need to be done as part of #1950 as parsing of diff patches is a shared block of code (used by refactoring and sorting of imports).

  8. ImageDon Jayamanne (DonJayamanne)
    removed their assignment
    on Jun 13, 2018
  9. ImageBrett Cannon (brettcannon)
    added
    x-black
    on Jun 15, 2018
  10. ImageBrett Cannon (brettcannon)
    removed this from the Jul 2018 milestone on Jul 19, 2018

  11. marko-knoebl commented on Aug 6, 2018

    @marko-knoebl
    Marko Knöbl (marko-knoebl)
    on Aug 6, 2018

    FYI, I've also come across cases where this will add an extra newline (and not just fail to remove it):

    If there's no newline at the end of the file yet and the last line contains something that will be reformatted by black then auto-formatting will add two blank lines.

    example:

    a=0

    will be reformatted to:

    a = 0

  12. jaswilli commented on Oct 6, 2018

    @jaswilli
    Jason Williams (jaswilli)
    on Oct 6, 2018

    Since #1950 has been closed is there another issue that can be tracked to see progress on this?

  13. brettcannon commented on Oct 9, 2018

    @brettcannon
    Brett Cannon (brettcannon)
    on Oct 9, 2018
    Member

    Jason Williams (@jaswilli) this issue is tracking the overall issue. If you're curious about the work in the language server to potentially take this functionality over, then microsoft/python-language-server#143 has that request.

  14. ImageBrett Cannon (brettcannon)
    removed
    x-black
    on Nov 20, 2018

  15. drorata commented on Aug 22, 2019

    @drorata
    Dror Atariah (drorata)
    on Aug 22, 2019

    Is there any update on this issue? I am still having it with Vscode 1.37.1 and vscode-python 2019.8.30787.

  16. brettcannon commented on Aug 22, 2019

    @brettcannon
    Brett Cannon (brettcannon)
    on Aug 22, 2019
    Member

    Dror Atariah (@drorata) not specifically. Other bugs have taken precedence. As always, if the 👍 gets high enough we will prioritize fixing this appropriately (this issue currently sits at #23 on that list).

    Otherwise we will happily review a PR that tries to fix this if someone is motivated enough to provide one.

  17. ashleybartlett commented on Aug 28, 2019

    @ashleybartlett
    Ashley Bartlett (ashleybartlett)
    on Aug 28, 2019

    I have just run into this issue. From the cli, black will change the file correctly. When saving, It will format the rest of the document, and leaves the extra blank line/ I even see the same flake8 picking this up as a formatting error.

    If I have no blank lines, it adds one, if I have multiple it removes all but 2. I tried this out with a new file and found the same result.

    This caught me out, as our CI pipeline runs black --check and fails. Which it did.

  18. ImageGraham Wheeler (gramster)
    added
    area-editor-*User-facing catch-all
    on Oct 10, 2019

  19. roberthubblehq commented on Jan 10, 2020

    @roberthubblehq
    roberthubblehq
    on Jan 10, 2020

    { "files.trimFinalNewlines": true } in settings.json seems to fix this.

  20. ImageBrett Cannon (brettcannon)
    added
    reason-preexisting
    on Jan 14, 2020
  21. ImageLuciana Abud (luabud)
    closed this as completedon May 7, 2020
  22. ghost removed
    needs PR
    on May 7, 2020
  23. Imagelock
    locked as resolved and limited conversation to collaborators on May 20, 2020
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