Re: [PATCH] upload-pack: use buffered I/O to talk to rev-list

> One suggestion here:
> 
> On Sun, Aug 2, 2020 at 7:41 AM René Scharfe <l.s.r@web.de> wrote:
>> Like f0bca72dc77 (send-pack: use buffered I/O to talk to pack-objects,
>> 2016-06-08), significantly reduce the number of system calls and
>> simplify the code for sending object IDs to rev-list by using stdio's
>> buffering and handling errors after the loops.
>>
>> Signed-off-by: René Scharfe <l.s.r@web.de>
>> ---
>>  upload-pack.c | 21 +++++++--------------
>>  1 file changed, 7 insertions(+), 14 deletions(-)
>>
>> diff --git a/upload-pack.c b/upload-pack.c
>> index 86737410709..9f616c2c6a6 100644
>> --- a/upload-pack.c
>> +++ b/upload-pack.c
> 
> [snip]
> 
>> @@ -640,12 +636,11 @@ static int do_reachable_revlist(struct child_process *cmd,
>>                 }
>>                 if (reachable && o->type == OBJ_COMMIT)
>>                         o->flags |= TMP_MARK;
>> -               memcpy(namebuf, oid_to_hex(&o->oid), hexsz);
>> -               if (write_in_full(cmd->in, namebuf, hexsz + 1) < 0)
>> -                       goto error;
>> +               fprintf(cmd_in, "%s\n", oid_to_hex(&o->oid));
> 
> The fprintf() call here *can* return an error, e.g., if the
> connection has died.  If it does, it should set things up so that
> a later ferror(cmd_in) returns true.