Re: [PATCH] Strip trailing newlines from input string

[Luis Machado <luis.machado@arm.com>]

On 4/8/24 18:18, Tom Tromey wrote:
> A co-worker noticed a strange situation where "target remote" would
> fail due to a trailing newline in the address part of the command.
> Eventually he tracked this down to the fact that he was pasting the
> command into the terminal, and due to bracketed paste mode, the
> newline was being preserved by readline.
> 
> It seems to me that we basically never want a trailing newline on a
> gdb command, so this patch removes it when handling the readline
> result.
> 
> Co-Authored-By: Kévin Le Gouguec <legouguec@adacore.com>
> ---
>  gdb/event-top.c                          |  8 +++++
>  gdb/testsuite/gdb.base/paste-newline.exp | 45 ++++++++++++++++++++++++
>  2 files changed, 53 insertions(+)
>  create mode 100644 gdb/testsuite/gdb.base/paste-newline.exp
> 
> diff --git a/gdb/event-top.c b/gdb/event-top.c
> index 9a02ac6df27..f0c07ba7f64 100644
> --- a/gdb/event-top.c
> +++ b/gdb/event-top.c
> @@ -251,6 +251,14 @@ gdb_rl_callback_handler (char *rl) noexcept
>    static struct gdb_exception gdb_rl_expt;
>    struct ui *ui = current_ui;
>  
> +  /* In bracketed paste mode, pasting a complete line can result in a
> +     literal newline appearing at the end of LINE.  However, we never
> +     want this in gdb.  */
> +  size_t len = strlen (rl);
> +  while (len > 0 && (rl[len - 1] == '\r' || rl[len - 1] == '\n'))
> +    --len;
> +  rl[len] = '\0';
> +
>    try
>      {
>        /* Ensure the exception is reset on each call.  */
> diff --git a/gdb/testsuite/gdb.base/paste-newline.exp b/gdb/testsuite/gdb.base/paste-newline.exp
> new file mode 100644
> index 00000000000..b886fae6871
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/paste-newline.exp
> @@ -0,0 +1,45 @@
> +# Copyright (C) 2024 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# This test script checks that a trailing newline is stripped from a
> +# bracketed paste.
> +
> +save_vars { env(TERM) env(INPUTRC) } {
> +    setenv TERM ansi
> +
> +    # Create an inputrc file that enables bracketed paste mode.
> +    set inputrc [standard_output_file inputrc]
> +    set fd [open "$inputrc" w]
> +    puts $fd "set enable-bracketed-paste on"
> +    close $fd
> +
> +    setenv INPUTRC "$inputrc"
> +
> +    clean_restart
> +
> +    send_gdb "\033\[200~echo hello\n\033\[201~\n"
> +
> +    gdb_test_multiple "" "newline removed from paste" {
> +	-re "hello\[^\n\]*$gdb_prompt $" {
> +	    # Some escape sequences are expected between echo's output
> +	    # and the prompt (e.g. the paste-bracketing toggle
> +	    # sequences) but _newlines_ are not.
> +	    pass $gdb_test_name
> +	}
> +	-re "hello.*\r\n.*$gdb_prompt $" {
> +	    fail $gdb_test_name
> +	}
> +    }
> +}

Looks good to me.

Approved-By: Luis Machado <luis.machado@arm.com>
Tested-By: Luis Machado <luis.machado@arm.com>