[pacman-dev] [PATCH] getcols: return 0 when not attached to a tty

[Dave Reisner]

On Mon, Aug 11, 2014 at 09:51:19AM -0400, Andrew Gregory wrote:
> Scripts that parse pacman's output (like pacsearch) generally do not
> want wrapped lines.
> 
> Signed-off-by: Andrew Gregory <andrew.gregory.8 at gmail.com>
> ---

I agree there's a bug here, but this doesn't seem like the right fix...

>  src/pacman/util.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/src/pacman/util.c b/src/pacman/util.c
> index 6a095fd..de103b6 100644
> --- a/src/pacman/util.c
> +++ b/src/pacman/util.c
> @@ -46,7 +46,7 @@
>  #include "conf.h"
>  #include "callback.h"
>  
> -static int cached_columns = 0;
> +static int cached_columns = -1;
>  
>  struct table_cell_t {
>  	char *label;
> @@ -158,7 +158,7 @@ static int flush_term_input(int fd)
>  
>  void columns_cache_reset(void)
>  {
> -	cached_columns = 0;
> +	cached_columns = -1;
>  }
>  
>  static int getcols_fd(int fd)
> @@ -189,10 +189,15 @@ unsigned short getcols(void)
>  	const char *e;
>  	int c = 0;
>  
> -	if(cached_columns > 0) {
> +	if(cached_columns >= 0) {
>  		return cached_columns;
>  	}
>  
> +	if(!isatty(STDOUT_FILENO)) {
> +		cached_columns = 0;
> +		return 0;
> +	}
> +

Doing this means that you can no longer use COLUMNS to control output
width when not attached to a TTY.

>  	e = getenv("COLUMNS");
>  	if(e) {
>  		c = strtol(e, NULL, 10);

What isn't shown in the context here is that columns_fd is called next
to determine the width of the terminal. I think we should add the isatty
check there and then accept '0' as a valid return from that function.

> -- 
> 2.0.1
>