[libvirt] [PATCH] docs: ensure outputfile is deleted if rst2html/rst2man fail

[Eric Blake]

On 12/11/19 12:45 PM, Daniel P. Berrangé wrote:
> This avoids leaving a zero length or partially generated output
> file on errors.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>   docs/Makefile.am | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/docs/Makefile.am b/docs/Makefile.am
> index eb8de80b9c..9a1f7a6117 100644
> --- a/docs/Makefile.am
> +++ b/docs/Makefile.am
> @@ -259,21 +259,21 @@ man8_MANS = $(manpages8_rst:%.rst=%.8)
>   	   grep -v '^\.\. contents::' < $< | \
>   	   sed -e 's|SYSCONFDIR|$(sysconfdir)|g' \
>   	       -e 's|RUNSTATEDIR|$(runstatedir)|g' | \
> -	   $(RST2MAN) > $@
> +	   $(RST2MAN) > $@ || { rm $@ && exit 1; }

But still allows a truncated view of the file if another process 
accesses the file while RST2MAN is still running.  Even better is to 
generate output to a temp file then atomically mv it into place, so that 
no concurrent process can ever see an incomplete file.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org