Re: [RFC] sending errors to stdout under $PAGER

From: Shawn O. Pearce <spearce@spearce.org>
Date: Feb 17, 2008, 07:50 UTC
Message-ID: <20080217075033.GP24004@spearce.org>
In-Reply-To: <7vbq6g90gy.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> wrote:

Show 9 quoted lines

> Because we spawn the pager as the foreground process and feed
> its input via pipe from the real command, we cannot affect the
> exit status the shell sees from git command when the pager is in
> use (I think there is not much gain we can have by working it
> around, though).  But at least it may make sense to show the
> error message to the user sitting in front of the pager, perhaps
> like this.
> 
> What do people think?  Have I overlooked any downsides?

I think this is a good idea.

If you are using an interactive pager, you have asked for the content to come to you through that. Not unlike how I have chosen to have the content come to me through a virtual pty and not a printer with green-and-white bar paper. :)

I've been bitten by this in the past a few times, but I have also been knowledgable enough about git, the command I ran, and the project I ran it on to realize something wasn't right with the output I am seeing in the pager and retry without the pager to see the real error(s).

Show 16 quoted lines

> +++ b/usage.c
> @@ -4,12 +4,15 @@
>   * Copyright (C) Linus Torvalds, 2005
>   */
>  #include "git-compat-util.h"
> +#include "cache.h"
>  
>  static void report(const char *prefix, const char *err, va_list params)
>  {
>  	char msg[256];
> +	FILE *outto = (pager_in_use() ? stdout : stderr);
> +
>  	vsnprintf(msg, sizeof(msg), err, params);
> -	fprintf(stderr, "%s%s\n", prefix, msg);
> +	fprintf(outto, "%s%s\n", prefix, msg);
>  }

-- 
Shawn.