Re: [BUG] git cat-file does not terminate

On Fri, Mar 04, 2011 at 02:04:00PM +0100, Robert Wruck wrote:

Hi,

this is some strange behaviour of cat-file:
On a certain file, `git cat-file blob <objectname>` writes an
endless stream repeating the first 4096 byte of the original file.
cat-file -s and cat-file -t produce correct results.

Even stranger: This only happens with cygwin-git (1.7.4.1).
msysgit (same machine, same repository): works
linux-git (same machine, same repository): works

Even more strange: This only happens with cygwin on a particular
machine (recent cygwin1.dll 1.7.8) under WinXP/32bit. On another
machine, recent cygwin, Windows7/64bit it works...

Debugging a bit, I found that the following happens:
In xwrite (wrapper.c), write() is called with the total file size -
in my case about 87 MB. This call returns -1 and EAGAIN but
nevertheless writes 4096 byte to the output fd. I don't think that's
expected behaviour...

I "fixed" it by limiting each write to 64k (thus looping in
write_in_full) but maybe somebody knows about that cygwin behaviour?

This seems to be the cause of the dreaded "No newline found after
blob" when running `git svn clone` under cygwin on a repository with
large files.

You could argue that this is a cygwin bug but maybe limiting each
write to a maximum size is a simple workaround.

Maybe you could post a patch, so everyone can see the technical implications
and discuss the fix?

-Peter