Re: [RFC] gdb.cp/static-print-quit.exp: fix racy tests (PR testsuite/12649)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Thu, 05 May 2011 20:03:32 +0200, Marek Polacek wrote:
[...]
> We can prevent this if we, in our gdb_test_multiple, create a "<return>"
> case with `exp_continue'.  Nonetheless, except this, we must also in this
> case:
> 
>     -re " to quit---$" {
>         fail $test
>         return -1
>     }

Found comments for the testcase were:
	[patch] Fix memory corruption on aborted object print
	http://sourceware.org/ml/gdb-patches/2010-06/msg00632.html
	47c8c764a9be6d023eca450336e6d9de16970fc0

The " to quit---$" case was there probably for the gdb-7.1 case which is
missing the "static field" output, put there untested now.  I understand this
is a change of the testcase.


> differentiate between success and failure, since after processing the "<return>"
> part we now have in the buffer " to quit---".  Thus, it is possible to do
> something like this, using a new variable `seen_return', although I must say, I don't
> like it at all.

exp_continue/variables make it complicated, I would prefer splitting it to
multiple consecutive test cases.


> set test "print c"
> set seen_return 0
> gdb_test_multiple $test $test {
>     "<return>" {
> 	incr seen_return
> 	exp_continue
>     }

BTW you do not need to match exactly "<return>" as is in lib/gdb.exp - it is
enough to match any string ending with "<return>".


On Thu, 05 May 2011 20:12:07 +0200, Marek Polacek wrote:
> I should have add a diff as well, here it is:
[...]
> -    -re " = \{loooooooooooooooooooooooooooooooooooooooooooooong = 0, static field = \{\r\n---Type <return> to continue, or q <return> to quit---$" {
> -       pass $test
> +    "<return>" {
> +       incr seen_return

FYI the diff could not be applied as it has <tab>s converted to spaces.

Any comments?  I will check it in otherwise.

Tested on x86_64-fedora15-linux-gnu.


Thanks,
Jan


gdb/testsuite/
2011-05-06  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix a race.
	* gdb.cp/static-print-quit.exp (print c): Split to ...
	(print c - <return>, print c - q <return>, print c - to quit):
	... these.  Make the testfile untested on gdb-7.1.

--- a/gdb/testsuite/gdb.cp/static-print-quit.exp
+++ b/gdb/testsuite/gdb.cp/static-print-quit.exp
@@ -30,14 +30,29 @@ clean_restart $executable
 gdb_test_no_output "set width 80"
 gdb_test_no_output "set height 2"
 
-set test "print c"
-gdb_test_multiple $test $test {
-    -re " = \{loooooooooooooooooooooooooooooooooooooooooooooong = 0, static field = \{\r\n---Type <return> to continue, or q <return> to quit---$" {
+set test "print c - <return>"
+gdb_test_multiple "print c" $test {
+    -re "\\$\[0-9\]+ = \{loooooooooooooooooooooooooooooooooooooooooooooong = 0, static field = \{\r\n---Type <return>" {
 	pass $test
     }
+    -re "\r\n---Type <return>" {
+	# gdb-7.1 did not crash with this testcase but it had the same bug.
+	untested ${testfile}.exp
+	return 0
+    }
+}
+
+set test "print c - q <return>"
+gdb_test_multiple "" $test {
+    -re " to continue, or q <return>" {
+	pass $test
+    }
+}
+
+set test "print c - to quit"
+gdb_test_multiple "" $test {
     -re " to quit---$" {
-	fail $test
-	return -1
+	pass $test
     }
 }