Re: [PATCH v3] sha1_file: pass empty buffer to index empty file

> Subject: [PATCH] copy.c: make copy_fd() report its status silently
>
> When copy_fd() function encounters errors, it emits error messages
> itself, which makes it impossible for callers to take responsibility
> for reporting errors, especially when they want to ignore certaion

> errors.
>
> Move the error reporting to its callers in preparation.
>
>  - copy_file() and copy_file_with_time() by indirection get their
>    own calls to error().
>
>  - hold_lock_file_for_append(), when told to die on error, used to
>    exit(128) relying on the error message from copy_fd(), but now it
>    does its own die() instead.  Note that the callers that do not
>    pass LOCK_DIE_ON_ERROR need to be adjusted for this change, but
>    fortunately there is none ;-)
>
>  - filter_buffer_or_fd() has its own error() already, in addition to
>    the message from copy_fd(), so this will change the output but
>    arguably in a better way.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>