Re: [PATCH 2/2] [gdb] Don't use gdb_stdlog for inferior-events

[Simon Marchi <simark@simark.ca>]

On 2021-11-15 6:21 a.m., Tom de Vries via Gdb-patches wrote:
> The test-case gdb.base/foll-vfork.exp contains:
> ...
> if [gdb_debug_enabled] {
>     untested "debug is enabled"
>     return 0
> }
> ...
>
> To understand what it does, I disabled this bit and ran with GDB_DEBUG=infrun,
> like so:
> ...
> $ cd $build/gdb/testsuite
> $ make check GDB_DEBUG=infrun RUNTESTFLAGS=gdb.base/foll-vfork.exp

Interesting, I didn't know about that.

> ...
> and ran into:
> ...
> (gdb) PASS: gdb.base/foll-vfork.exp: exec: \
>   vfork parent follow, through step: set follow-fork parent
> next^M
> 33        if (pid == 0) {^M
> (gdb) FAIL: gdb.base/foll-vfork.exp: exec: \
>   vfork parent follow, through step: step
> ...
>
> The problem is that the test-case expects:
> ...
> (gdb) PASS: gdb.base/foll-vfork.exp: exec: \
>   vfork parent follow, through step: set follow-fork parent
> next^M
> [Detaching after vfork from child process 28169]^M
> 33        if (pid == 0) {^M
> (gdb) PASS: gdb.base/foll-vfork.exp: exec: \
>   vfork parent follow, through step: step
> ...
> but the "Detaching" line has been redirected to
> $outputs/gdb.base/foll-vfork/gdb.debug.
>
> I looked at the documentation of "set logging debugredirect [on|off]":
> ...
>   By default, GDB debug output will go to both the terminal and the logfile.
>   Set debugredirect if you want debug output to go only to the log file.
> ...
> and my interpretation of it was that "debug output" did not match the
> "messages" description of inferior-events:
> ...
> The set print inferior-events command allows you to enable or disable printing
> of messages when GDB notices that new inferiors have started or that inferiors
> have exited or have been detached.
> ...
>
> Fix the discrepancy by not redirecting inferior-events for debugredirect.
> [ Alternatively, we could update the documentation to clarify that debug
> output also implies inferior-events messsages. ]
>
> Update the gdb.base/foll-vfork.exp test-case to not require
> gdb_debug_enabled == 0.
>
> Tested on x86_64-linux.
>
> Tested test-case gdb.base/foll-vfork.exp with and without GDB_DEBUG=infrun.

I think the patch is doing the right thing, LGTM.

Simon