Re: [msysGit] Re: Git for Windows and line endings

From: Raja R Harinath <harinath@hurrynot.org>
Date: Nov 4, 2012, 12:37 UTC
Message-ID: <878vahee72.fsf@hariville.hurrynot.org>
In-Reply-To: <CADKp0pxuFsSEeZoeemyaqhSJEcsjj1arEOsF4Ub8=76y7tkwHg@mail.gmail.com>

Hi,

Chris B <chris.blaszczynski@gmail.com> writes: [snip]

Show 14 quoted lines

> - Windows has been able to cope with UNIX line endings a long time; no
> developer is using a default Notepad to open files with high
> expectations. Any Windows development tool and editor worth anything
> I've used is able to handle both just fine.
> - VIM also handles Windows line endings just fine as well. I just
> tested it on a Linux machine. Maybe old version? (pure VI is not even
> on this machine but hard to press these days it can't handle it.)
> - The files in .git folder are in UNIX format anyway, so why are those
> not also included in line ending changes? Isn't is because there is a
> Windows app (msysgit) running on Windows that expects the UNIX line
> ending? So in the same manor, someone might have a Windows system
> using some Cygwin components perhaps, or a Windows C program possibly
> poorly written or just old, that demand some text files to be left
> alone in the format we saved it.

There are several subtleties in LF handling with mixed systems. Here's my write-up in:

  https://github.com/mono/mono/blob/master/.gitattributes

for an example set of trade-offs.  Quoting in full since it's fairly short.

- Hari

# CRLF Handling # ------------- # # The ideal situation would be to do no EOL normalization. Each file # would have a default EOL, and tools on Windows and Linux would handle # both EOL formats. # # We're not in the ideal world. A popular editor on Windows (possibly # Visual Studio) silently introduces EOL corruption -- it displays an # LF-file normally, but any newly added lines have CRLF. On Linux, # Emacs and versions of VI handle LF-files and CRLF-files properly. # However, emacs doesn't like files with both LF and CRLF EOLs. Editing # the file without additional action will increase the EOL corruption # in the file. # # Another vector for mixed EOLs is scripts. We mostly don't have scripts # that add new lines -- so we rarely see this. However, one major event # in the tree was the addition of copyright headers using a script. That # script introduced EOL corruption. # # Any automated EOL normalization of files already in the repository will # cause difficulties in traversing histories, assigning blame, etc. So, we # don't want to change what's in the repository significantly, even if it # causes trouble. # # What we do now: # # a) we ensure that there's no further corruption of LF-files. So, we use # git's 'crlf' attribute on those files to ensure that things are fine # when we work on Windows. We could use 'crlf=input', but it doesn't buy # us much -- we might as well be working with consistent EOLs for files in # working directories as well as in the repository # # b) if the file already of CRLFs, we don't do any normalization. We use '-crlf' # so that git doesn't do any EOL-conversion of the file. As I said, this # is mostly harmless on Linux. We can't mark these files as 'crlf' or use # the new (git 1.7.2) 'eol=crlf' attribute, since it changes the contents # _inside_ the repository [1], and hence makes history traversal annoying. # So, we live with occasional EOL corruption. # # c) We can handle mixed-EOL files on a case-by-case basis, converting them to # LF- or CRLF-files based on which causes fewer lines to change # # d) We try to ensure no further headaches, by declaring EOL normalization on # code files, and Unix-flavoured files, like shell-scripts, makefiles, etc. # # [1] GIT use LFs as the normalized internal representation.