[Pingv3] [PATCH v3] gdb/testsuite: fix completion tests when using READ1

[Guinevere Larsen <blarsen@redhat.com>]

Ping!

-- 
Cheers,
Guinevere Larsen
She/Her/Hers

On 28/08/2023 13:30, Guinevere Larsen wrote:
> The commit a3da2e7e550c4fe79128b5e532dbb90df4d4f418 has introduced
> regressions when testing using the READ1 mechanism. The reason for that
> is the new failure path in proc test_gdb_complete_tab_unique, which
> looks for GDB suggesting more than what the test inputted, but not the
> correct answer, followed by a white space. Consider the following case:
>
> int foo(int bar, int baz);
>
> Sending the command "break foo<tab>" to GDB will return
>
> break foo(int, int)
>
> which easily fits the buffer in normal testing, so everything works, but
> when reading one character at a time, the test will find the partial
> "break foo(int, " and assume that there was a mistake, so we get a
> spurious FAIL.
>
> That change was added because we wanted to avoid forcing a completion
> failure to fail through timeout, which it had to do because there is no
> way to verify that the output is done, mostly because when I was trying
> to solve a different problem I kept getting reading errors and testing
> completion was frustrating.
>
> This commit implements a better way to avoid that frustration, by first
> testing gdb's complete command and only if that passes we will test tab
> completion. The difference is that when testing with the complete
> command, we can tell when the output is over when we receive the GDB
> prompt again, so we don't need to rely on timeouts. With this, the
> change to test_gdb_complete_tab_unique has been removed as that test
> will only be run and fail in the very unlikely scenario that tab
> completion is different than command completion.
> ---
>   gdb/testsuite/lib/completion-support.exp | 31 +++++++++++++++---------
>   1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/gdb/testsuite/lib/completion-support.exp b/gdb/testsuite/lib/completion-support.exp
> index fdc512838c3..56c0eee8e1d 100644
> --- a/gdb/testsuite/lib/completion-support.exp
> +++ b/gdb/testsuite/lib/completion-support.exp
> @@ -111,15 +111,11 @@ proc test_gdb_complete_tab_unique { input_line complete_line_re append_char_re }
>   
>       set test "tab complete \"$input_line\""
>       send_gdb "$input_line\t"
> -    set partial_complete [string_to_regexp $input_line]
>       set res 1
>       gdb_test_multiple "" "$test" {
>   	-re "^$complete_line_re$append_char_re$" {
>   	    pass "$test"
>   	}
> -	-re "$partial_complete\[^ \]+ $" {
> -	    fail "$test"
> -	}
>   	timeout {
>   	    fail "$test (timeout)"
>   	    set res -1
> @@ -194,17 +190,21 @@ proc test_gdb_complete_cmd_none { line } {
>   proc test_gdb_complete_cmd_unique { input_line complete_line_re } {
>       global gdb_prompt
>   
> +    set res 0
>       set cmd "complete $input_line"
>       set cmd_re [string_to_regexp $cmd]
>       set test "cmd complete \"$input_line\""
>       gdb_test_multiple $cmd $test {
>   	-re "^$cmd_re\r\n$complete_line_re\r\n$gdb_prompt $" {
>   	    pass $test
> +	    set res 1
>   	}
>   	-re "$gdb_prompt $" {
>   	    fail "$test"
> +	    set res -1
>   	}
>       }
> +    return $res
>   }
>   
>   # Test that completing "CMD_PREFIX + COMPLETION_WORD" with the
> @@ -263,12 +263,6 @@ proc test_gdb_complete_none { input_line } {
>   
>   proc test_gdb_complete_unique_re { input_line complete_line_re {append_char " "} {max_completions 0}} {
>       set append_char_re [string_to_regexp $append_char]
> -    if { [readline_is_used] } {
> -	if { [test_gdb_complete_tab_unique $input_line $complete_line_re \
> -		  $append_char_re] == -1 } {
> -	    return -1
> -	}
> -    }
>   
>       # Trim COMPLETE LINE, for the case we're completing a command with leading
>       # whitespace.  Leading command whitespace is discarded by GDB.
> @@ -288,7 +282,22 @@ proc test_gdb_complete_unique_re { input_line complete_line_re {append_char " "}
>   	    "\r\n$input_line_re $max_completion_reached_msg_re"
>       }
>   
> -    test_gdb_complete_cmd_unique $input_line $expected_output_re
> +    # First test completion with the command, then with tab.
> +    # It is done in this order because cmd_complete knows when the output
> +    # from GDB is over, so it can fail without requiring a timeout, which
> +    # speeds up testing if necessary.
> +
> +    if { [test_gdb_complete_cmd_unique $input_line\
> +		$expected_output_re] == -1 } {
> +	return -1
> +    }
> +
> +    if { [readline_is_used] } {
> +	if { [test_gdb_complete_tab_unique $input_line $complete_line_re \
> +		  $append_char_re] == -1 } {
> +	    return -1
> +	}
> +    }
>       return 1
>   }
>