[committed][gdb/testsuite] Fix gdb.base/define.exp with check-read1

[Tom de Vries <tdevries at suse dot de>]

[ was: Re: [PATCH v2] Restore original GDB prompt in define.exp ]
On 09-07-19 09:17, Richard Bunt wrote:
> Restore original GDB prompt in define.exp
> 
> define.exp will fail on a GDB which has set a custom prompt to identify
> itself.  This is because the test resets the prompt to a hard coded
> "(gdb)" but then verifies the success of this against the value in
> $gdb_prompt, which is set to the custom prompt.
> 
> The original approach to fix this involved resetting the prompt to
> $gdb_prompt rather than a hard coded "(gdb)". However it was noted during
> review that $gdb_prompt is a regular expression rather than a string.
> This is problematic because in general the prompt would be reset to a
> regular expression rather than an instance of a string accepted by said
> regular expression.
> 
> The fix used in commit avoids the above issue by capturing the literal
> prompt from running "show prompt" and uses this literal to restore the
> previous prompt.
> 
> Regression tested with GCC 7.3.0 on x86_64, ppc64le, aarch64.
> 
> gdb/testsuite/ChangeLog:
> 
> 2019-07-04  Richard Bunt  <richard.bunt@arm.com>
> 	Stephen Roberts  <stephen.roberts@arm.com>
> 
> 	* gdb.base/define.exp: Restore original prompt.
> 
> ---
>  gdb/testsuite/gdb.base/define.exp | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/testsuite/gdb.base/define.exp b/gdb/testsuite/gdb.base/define.exp
> index 0590da9..e8508b8 100644
> --- a/gdb/testsuite/gdb.base/define.exp
> +++ b/gdb/testsuite/gdb.base/define.exp
> @@ -283,6 +283,15 @@ gdb_test_multiple "define target hookpost-testsuite" "" {
> 
>  gdb_test "target testsuite" "one\r\nhello\r\ntwo" "target testsuite with hooks"
> 
> +# Save the GDB prompt so it can be restored to the original value later.
> +set prior_prompt ""
> +gdb_test_multiple "show prompt" "save gdb_prompt" {
> +    -re "Gdb's prompt is \"($gdb_prompt) \"\.\[\r\n\]*$gdb_prompt $" {
> +	set prior_prompt $expect_out(1,string)
> +	pass "save gdb_prompt"
> +    }
> +}
> +
>  # This is a quasi-define command: Verify that the user can redefine
>  # GDB's gdb_prompt.
>  #
> @@ -292,7 +301,7 @@ gdb_test_multiple "set prompt \\(blah\\) " "set gdb_prompt" {
>      }
>  }
> 
> -gdb_test_multiple "set prompt \\(gdb\\) " "reset gdb_prompt" {
> +gdb_test_multiple "set prompt $prior_prompt " "reset gdb_prompt" {
>      -re "$gdb_prompt $" {
>  	pass "reset gdb_prompt"
>      }
> 

This seems to have caused a check-read1 regression.

Fixed by patch below, committed to trunk.

Thanks,
- Tom

[gdb/testsuite] Fix gdb.base/define.exp with check-read1

When running gdb.base/define.exp with check-read1, we get:
...
show prompt^M
Gdb's prompt is "(gdb) ".^M
(gdb) PASS: gdb.base/define.exp: save gdb_prompt
set prompt \(blah\) ^M
(blah) PASS: gdb.base/define.exp: set gdb_prompt
set prompt (gdb) PASS: gdb.base/define.exp: reset gdb_prompt
^M
(gdb) FAIL: gdb.base/define.exp: define do-define
...

The problem is that the "$gdb_prompt $" regexp here:
...
gdb_test_multiple "set prompt $prior_prompt " "reset gdb_prompt" {
    -re "$gdb_prompt $" {
        pass "reset gdb_prompt"
    }
}
...
triggers for the echoing of the command "set prompt $prior_prompt " rather
than for the prompt after the command has executed.

Fix this by changing the regexp to "\r\n$gdb_prompt $".

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2019-07-29  Tom de Vries  <tdevries@suse.de>

	* gdb.base/define.exp: Add "\r\n" to "reset gdb_prompt" regexp.

---
 gdb/testsuite/gdb.base/define.exp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.base/define.exp b/gdb/testsuite/gdb.base/define.exp
index e8508b8728..d7d4fd03ba 100644
--- a/gdb/testsuite/gdb.base/define.exp
+++ b/gdb/testsuite/gdb.base/define.exp
@@ -302,7 +302,7 @@ gdb_test_multiple "set prompt \\(blah\\) " "set gdb_prompt" {
 }
 
 gdb_test_multiple "set prompt $prior_prompt " "reset gdb_prompt" {
-    -re "$gdb_prompt $" {
+    -re "\r\n$gdb_prompt $" {
 	pass "reset gdb_prompt"
     }
 }