Re: [PATCH] gdb/debuginfod: Prevent out_of_range exception

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2022-04-08 18:50, Aaron Merey via Gdb-patches wrote:
> Trailing whitespace in the string of debuginfod URLs causes an
> out_of_range exception during the printing of URLs for the first
> use notice.
> 
> To fix this, stop printing URLs when the substring to be printed
> consists only of whitespace.
> ---
>  gdb/debuginfod-support.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
> index 6c2d3fb2951..668c50c405c 100644
> --- a/gdb/debuginfod-support.c
> +++ b/gdb/debuginfod-support.c
> @@ -187,10 +187,13 @@ debuginfod_is_enabled ()
>        gdb::string_view url_view (urls);
>        while (true)
>  	{
> -	  url_view = url_view.substr (url_view.find_first_not_of (' '));
> +	  size_t off = url_view.find_first_not_of (' ');
> +	  if (off == gdb::string_view::npos)
> +	    break;
> +	  url_view = url_view.substr (off);
>  	  if (url_view.empty ())
>  	    break;


The change LGTM.  A test would be nice though, if not too complicated.

Also, I wonder if that url_view.empty() check is useful though.  Can it
really happen?

Simon