Re: GitForWindows vs. Cygwin
- Date: Wed, 21 Mar 2018 00:24:58 +0000
- From: Tony Kelman <tony@xxxxxxxxxx>
- Subject: Re: GitForWindows vs. Cygwin
>> Can anyone enlighten me about the relationship of "Git for Windows" to
> They are not related.
Yes, they are.
>> But now I hear of this GitForWindows thing. Which seems to have replaced
>> MSysGit, with a GUI thrown in. But is it _still_ a stale fork of Cygwin, or a
>> fork at all? Is it descended from MSysGit? I have been googling all over,
>> but not finding good answers.
GitForWindows 2.x is based on MSYS2, which doesn't share any non-cygwin
code with the old MSYS1 as far as I'm aware, but it reimplements (on
top of a much more up-to-date fork of cygwin) the path-mangling trick
that was the main motivating factor for using MSYS1 in the first place.
When you have a non-cygwin windows executable (one compiled by mingw.org,
or mingw-w64, or MSVC compilers) and try to pass it a posix/cygwin-style
absolute path, the windows executable won't usually recognize it as a
file that exists. What the MSYS shell does is apply a heuristic that
automatically translates posix-style absolute paths to Windows paths
(similar to manually calling `cygpath -w /posix/style/path` on each
argument within cygwin) before passing the argument to the executable.
There are other differences between MSYS2 and Cygwin, mostly that it
uses a different package manager and repository, but these are less
significant with respect to GitForWindows' requirements.
The git.exe in Cygwin's git package is a cygwin executable compiled
by cygwin's gcc. Hence it understands posix-style paths just fine,
but it depends on cygwin1.dll to do so, and may not perform as well as
a non-cygwin Windows executable. (Maybe someone has benchmarked this.)
GitForWindows has historically been compiled using mingw gcc -
the legacy and now-mostly-obsolete mingw.org in the git 1.x timeframe
(this is the reason there was not a 64 bit version of git.exe through
that release channel at the time), and more recently the mingw-w64
compilers for git 2.x. Many of your questions are answered at
Some components used by git (any shell scripts, for example) require
some form of posix compatibility layer to function. The recent MinGit
has a busybox-based variant that can mostly avoid MSYS2 dependencies,
though it seems to have at least some small MSYS2 pieces remaining:
You can see exactly how the MSYS2 runtime used by GitForWindows differs
from the version used by the MSYS2 project itself by looking at the
git repo at https://github.com/git-for-windows/msys2-runtime/commits/master
and how MSYS2 differs from upstream cygwin by looking at the repos at
These "patch sets" tend to get rebased pretty frequently when new
cygwin releases come out upstream.
I dunno where else this history has been written down, but this is
my understanding of the development heritage. Any git and/or MSYS2
maintainers can correct me if anything I stated here is incorrect.
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