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 this 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:
2019-07-10  Richard Bunt  <richard.bunt@arm.com>
	Stephen Roberts  <stephen.roberts@arm.com>

	* gdb.base/define.exp: Restore original prompt.

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index fcf86bd..0118420 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-07-10  Richard Bunt  <richard.bunt@arm.com>
+       Stephen Roberts  <stephen.roberts@arm.com>
+
+       * gdb.base/define.exp: Restore original prompt.
+
 2019-07-09  Pedro Alves  <palves@redhat.com>
 
        * gdb.cp/catch-multi-stdlib.exp: Adjust expected "info

diff --git a/gdb/testsuite/gdb.base/define.exp b/gdb/testsuite/gdb.base/define.exp
index 0590da9..e8508b8 100644 (file)
--- 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"
     }