avh4/elm-format

Should elm-format preserve CRLF line endings in files?

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#596 opened on Feb 15, 2019

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 (5 comments) (1 reaction) (0 assignees)Haskell (1,329 stars) (148 forks)batch import
discussionhelp wantedplatform: Windows

Description

Apparently elm-format currently always converts files to LF line endings. I'm kinda surprised that I don't see any record of anyone noticing or complaining about this before -- if anyone has thoughts as to why that is, please comment below.

razzeee [] I build this (LSP elm-format wrapper) and it seems to work But there's one small annoyance where I'm not sure if it's Design or oversight elm-format always uses.. \n for newline even if it should be \r\n on windows for example

av [6:16 PM] oh, hmm, that’s interesting…. I’m surprised I don’t remember any windows users have ever reporting that as a bug before

razzeee [2:09 AM] git and your editor will mitigate this, but still operations on disk and unnessesary file changes

razzeee [2:24 AM] All elements with 0 are unchanged all with -1 mean remove. I'm diffing a local file with the return of elm-format fed via stdin. Pasted image at 2019-02-14, 11:24 AM

av [10:23 AM] ah, interesting. I’d be open to an elm-format PR to fix this — or having a github issue created to remind me to look at it sometime

razzeee [3:16 PM] Will do, just wanted to make sure it's not by design

razzeee [3:27 PM] this makes it seem like it is on purpose? https://github.com/avh4/elm-format/blob/master/tests/test-files/transform/WindowsEol.elm

av [5:26 PM]

elm-format converts all CRLF line-endings to LF.

ah, that was meant to mean “it currently does this”, not that there’s any reason it should I think I searched the past issues, and I don’t see any discussion about it, so maybe I just forgot, but I don’t see any reason why elm-format can’t keep the CRs — just that it doesn’t yet, and also it’s kinda interesting that no windows user has ever yet complained about it so yeah, I’m open to the change, but probably won’t be able to work on it myself for a while thanks for bringing it up!

razzeee [2:04 AM] will see if i can figure it out, but never did any haskell

av [10:30 AM] I would guess maybe a good approach would be, first figure out how in haskell we can even detect that CRLF is meant to be used instead of LF (I guess we’d want to determine that from the input file itself, since some windows users would be storing their Elm files with LF and others with CRLF, probably?) — and then maybe after that it might be as simple as having an option to Box.render that would join the lines with on vs the other. The complicated part might be in figuring out what edge cases to consider w/r to multiple string literals

Contributor guide

Tech stack
None
Domain
developer experiencetooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Haskell knowledgeunderstanding of elm format internalsfamiliarity with line ending handling
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The issue requests preserving CRLF line endings in elm format. The maintainer suggests detecting the desired line ending from the input file (some Windows users may use LF), then modifying the rendering to join lines with the appropriate newline. Relevant file: tests/test files/transform/WindowsEol.elm. The approach involves understanding how elm format reads and outputs files, and possibly adding an option to Box.render.