Re: Infinite loop in cascade_filter_fn()

On Fri, Nov 25, 2011 at 04:43:41PM +0100, Henrik Grubbström wrote:

On Wed, 23 Nov 2011, Henrik Grubbström wrote:

quoted

Hi.

My git repository walker just got bitten by what seems to be a
reasonably new bug in convert.c:cascade_filter_fn() (git 1.7.8.rc3
(gentoo)).

After some tracing, the problem is triggered by the variable "remaining"
being set to 1 in the beginning of the cascade_filter_fn() loop,
which causes filter "two" to be called with an output buffer size of
1.
Filter "two" in this case is lf_to_crlf_filter_fn(), and the next
input character is a "\n". lf_to_crlf_filter_fn() wants to convert
this to "\r\n", but that doesn't fit into the buffer, so it breaks
out and returns zero. Upon seing the zero cascade_filter_fn() thinks
all is well, even though nothing has happened, and loops.

The bug is probably that lf_to_crlf_filter_fn() should return
non-zero in this case (ie o and/or i being zero).

non-zero? That would cause the filter to abort, which definitely not
what we want. Have you seen my other e-mails regarding this? I'm
trying to figure out which is the best way to go about this. The
solution is to keep track of the fact that we're missing a LF in the
output buffer.

   cmn