Re: [PATCH][gdb/testsuite] Fix xpass in gdb.python/lib-types.exp

[Tom de Vries <tdevries@suse.de>]

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On 19-02-2020 22:28, Tom Tromey wrote:
>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
> 
> Tom> It's incorrect to xfail a gdb test-case for gcc bug.
> 
> I think we've used "kfail" for this in the past, though TBH I never
> truly understood the kfail/xfail distinction and I probably have it
> backward or something.
> 

I went to double check again at my xfail/kfail reference point (
https://opensource.apple.com/source/gdb/gdb-325/src/dejagnu/doc/dejagnu.texi.auto.html
), and found:
...
@item XFAIL
A test failed, but it was expected to fail.  This result indicates no
change in a known environment bug.  If a test fails because the
operating system where the test runs lacks some facility required by the
test (i.e. failure is due to the lack of a feature, not the existence of
a bug), the outcome is @code{UNSUPPORTED} instead.
...

So, I got the xfail and kfail mixed up, and in fact the xfail for a gcc
bug is valid use in the gdb testsuite. Oops.

I've now fixed the xpass by testing more precisely for the xfail.

Committed as attached.

Thanks,
- Tom

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[gdb/testsuite] Fix xpass in gdb.python/lib-types.exp

When running gdb.python/lib-types.exp, we have an xpass:
...
(gdb) python print (str (typedef_const_typedef_class1_ref_obj.type))^M
typedef_const_typedef_class1_ref^M
(gdb) XPASS: gdb.python/lib-types.exp: \
  python print (str (typedef_const_typedef_class1_ref_obj.type)) \
  (PRMS gcc/55641)
...

When running the same with gcc 4.8, we have an xfail instead:
...
(gdb) python print (str (typedef_const_typedef_class1_ref_obj.type))^M
const typedef_const_typedef_class1_ref^M
(gdb) XFAIL: gdb.python/lib-types.exp: \
  python print (str (typedef_const_typedef_class1_ref_obj.type)) \
  (PRMS gcc/55641)
...

Fix the xpass by xfailing only for the gcc 4.8 pattern.

Tested on x86_64-linux, with:
- gcc 7.5.0
- gcc 4.8.5
- clang 5.0.2

gdb/testsuite/ChangeLog:

2020-02-19  Tom de Vries  <tdevries@suse.de>

	* gdb.python/lib-types.exp: Make xfail more strict.

---
 gdb/testsuite/gdb.python/lib-types.exp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/gdb/testsuite/gdb.python/lib-types.exp b/gdb/testsuite/gdb.python/lib-types.exp
index ab1d9d8dad..d2d5f9b2b9 100644
--- a/gdb/testsuite/gdb.python/lib-types.exp
+++ b/gdb/testsuite/gdb.python/lib-types.exp
@@ -103,8 +103,15 @@ gdb_test_multiple "python print (str (basic_type_typedef_const_typedef_class1_ob
 # test nested typedef/reference stripping
 gdb_test_no_output "python typedef_const_typedef_class1_ref_obj = gdb.parse_and_eval ('typedef_const_typedef_class1_ref_obj')"
 gdb_test_no_output "python basic_type_typedef_const_typedef_class1_ref_obj = gdb.types.get_basic_type (typedef_const_typedef_class1_ref_obj.type)"
-if {[test_compiler_info {gcc-*-*}]} { setup_xfail gcc/55641 *-*-* }
-gdb_test "python print (str (typedef_const_typedef_class1_ref_obj.type))" "\[\r\n\]+typedef_const_typedef_class1_ref"
+gdb_test_multiple "python print (str (typedef_const_typedef_class1_ref_obj.type))" "" {
+    -re -wrap "\[\r\n\]+const typedef_const_typedef_class1_ref" {
+	# Compiler with PR gcc/55641.
+	xfail $gdb_test_name
+    }
+    -re -wrap "\[\r\n\]+typedef_const_typedef_class1_ref" {
+	pass $gdb_test_name
+    }
+}
 set test "nested typedef/ref stripping"
 gdb_test_multiple "python print (str (basic_type_typedef_const_typedef_class1_ref_obj))" $test {
     -re "\[\r\n\]+class1\[\r\n\]+$gdb_prompt $" {