Re: [PATCH] tests: create an interactive gdb session with the 'debug' helper

[Jeff King <peff@peff.net>]

On Fri, Mar 17, 2017 at 03:46:46PM +0100, SZEDER Gábor wrote:

> The 'debug' test helper is supposed to facilitate debugging by running
> a command of the test suite under gdb.  Unfortunately, its usefulness
> is severely limited, because that gdb session is not interactive,
> since the test's, and thus gdb's standard input is attached to
> /dev/null (for a good reason, see 781f76b15 (test-lib: redirect stdin
> of tests, 2011-12-15)).
> 
> Re-attach the original standard input in the debug helper, thus
> creating an interactive gdb session, which is much much more useful.

Yeah, I think I've had to do a similar hack manually. This is an obvious
improvement. Though...

> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
> index bd357704c..9567dc986 100644
> --- a/t/test-lib-functions.sh
> +++ b/t/test-lib-functions.sh
> @@ -154,7 +154,7 @@ test_pause () {
>  #
>  # Example: "debug git checkout master".
>  debug () {
> -	 GIT_TEST_GDB=1 "$@"
> +	 GIT_TEST_GDB=1 "$@" <&6
>  }

Your stderr and stdout may be redirected, too. That's usually not a big
problem because you'll be using "-v", but perhaps this should add:

  >&3 2>&4

to be on the safe side. That covers running without "-v", as well as
cases where the test script is redirecting output (I _actually_ wish gdb
behaved like perl's debugger and unconditionally used the terminal,
retaining existing redirections, but I AFAIK there's no easy way to get
it to do that).

-Peff