gdb/gdb-only-force-interp_console-ui_out-for-breakpoint-commands-in-mi-mode.patch

[gdb] Only force INTERP_CONSOLE ui_out for breakpoint commands in MI mode

The problem reported in PR mi/25055 is that the output of the backtrace
command, when executed as breakpoint command does not show when executing
using the MI interpreter:
...
$ gdb a.out
Reading symbols from a.out...
(gdb) break main
Breakpoint 1 at 0x4003c0: file test.c, line 19.
(gdb) commands
Type commands for breakpoint(s) 1, one per line.
End with a line saying just "end".
>bt
>end
(gdb) interpreter-exec mi "-exec-run"
^done

Breakpoint 1, main () at test.c:19
19        return foo (4);
(gdb)
...

Interestingly, the function print_frame is called twice during -exec-run:
- once during tui_on_normal_stop where the ui_out is temporarily set to
  tui->interp_ui_out (), resulting in the part after the comma in
  "Breakpoint 1, main () at test.c:19"
- once during execute_control_command, where the ui_out is the default for the
  current interpreter: mi_ui_out, which ignores calls to output text.

The commit 3a87ae656c2 "Use console uiout when executing breakpoint commands"
fixes the problem by temporarily switching to the ui_out of INTERP_CONSOLE in
execute_control_command.

This however caused a regression in redirection (escaping '#' using '\' for
git commit message convenience):
...
$ rm -f gdb.txt; gdb a.out
Reading symbols from a.out...
(gdb) break main
Breakpoint 1 at 0x4003c0: file test.c, line 19.
(gdb) commands
Type commands for breakpoint(s) 1, one per line.
End with a line saying just "end".
>bt
>end
(gdb) set logging redirect on
(gdb) set logging on
Redirecting output to gdb.txt.
Copying debug output to gdb.txt.
(gdb) run
\#0  main () at test.c:19
(gdb) q
A debugging session is active.

        Inferior 1 [process 22428] will be killed.

Quit anyway? (y or n) y
$ cat gdb.txt
Starting program: /data/gdb_versions/devel/a.out

Breakpoint 1, main () at test.c:19
19        return foo (4);
...

The problem is that the '#0  main () at test.c:19' ends up in the gdb output
output rather than in gdb.txt.  This is due to the fact that the redirect is
setup for the current ui_out (which is tui->interp_ui_out ()), while the
backtrace output is printed to the INTERP_CONSOLE ui_out.

Fix this by limiting switching to INTERP_CONSOLE ui_out to when INTERP_MI is
active.

Tested on x86_64-linux.

gdb/ChangeLog:

2019-10-02  Tom de Vries  <tdevries@suse.de>

	PR gdb/24956
	* cli/cli-script.c (execute_control_command): Only switch to
	INTERP_CONSOLE's ui_out when INTERP_MI is active.

gdb/testsuite/ChangeLog:

2019-10-02  Tom de Vries  <tdevries@suse.de>

	PR gdb/24956
	* gdb.base/ui-redirect.exp: Test output of user-defined command.

Change-Id: Id1771e7fcc9496a7d97ec2b2ea6b1487596f1ef7

---
 gdb/cli/cli-script.c                   |  3 +++
 gdb/testsuite/gdb.base/ui-redirect.exp | 47 +++++++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index 85f00c75b3f..4d216f15dae 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -697,6 +697,9 @@ execute_control_command_1 (struct command_line *cmd, int from_tty)
 enum command_control_type
 execute_control_command (struct command_line *cmd, int from_tty)
 {
+  if (!current_uiout->is_mi_like_p ())
+    return execute_control_command_1 (cmd, from_tty);
+
   /* Make sure we use the console uiout.  It's possible that we are executing
      breakpoint commands while running the MI interpreter.  */
   interp *console = interp_lookup (current_ui, INTERP_CONSOLE);
diff --git a/gdb/testsuite/gdb.base/ui-redirect.exp b/gdb/testsuite/gdb.base/ui-redirect.exp
index 1ebff790e57..ab85eb059a0 100644
--- a/gdb/testsuite/gdb.base/ui-redirect.exp
+++ b/gdb/testsuite/gdb.base/ui-redirect.exp
@@ -17,7 +17,10 @@ if { [prepare_for_testing "failed to prepare" ui-redirect start.c] } {
     return -1
 }
 
-gdb_breakpoint main
+if ![runto_main] {
+    fail "can't run to main"
+    return -1
+}
 
 set test "commands"
 gdb_test_multiple $test $test {
@@ -34,8 +37,50 @@ gdb_test_multiple $test $test {
 }
 gdb_test_no_output "end"
 
+with_test_prefix "userdefined" {
+    set test "define userdefined"
+    gdb_test_multiple $test $test {
+	-re "End with a line saying just \"end\"\\.\r\n>$" {
+	    pass $test
+	}
+    }
+
+    set test "bt"
+    gdb_test_multiple $test $test {
+	-re "\r\n>$" {
+	    pass $test
+	}
+    }
+
+    gdb_test_no_output "end"
+}
+
 gdb_test_no_output "set logging file /dev/null"
 gdb_test "set logging on" "Copying output to /dev/null\\."
 gdb_test "save breakpoints /dev/null" "Saved to file '/dev/null'\\."
+gdb_test "userdefined" "#0  main ().*"
 gdb_test "set logging off" "Done logging to /dev/null\\."
 gdb_test "help" "List of classes of commands:.*"
+
+with_test_prefix "redirect" {
+    gdb_test "set logging redirect on"
+    gdb_test "set logging on" \
+    "Redirecting output to /dev/null\\."
+    gdb_test_no_output "save breakpoints /dev/null" "Saved to file '/dev/null'\\."
+    gdb_test_no_output "userdefined"
+    gdb_test "set logging off" "Done logging to /dev/null\\."
+    gdb_test "help" "List of classes of commands:.*"
+}
+
+with_test_prefix "redirect while already logging" {
+    gdb_test_no_output "set logging redirect off"
+    gdb_test "set logging on" \
+    "Copying output to /dev/null\\."
+    gdb_test "set logging redirect on" \
+    ".*warning: Currently logging .*Turn the logging off and on to make the new setting effective.*"
+    gdb_test "save breakpoints /dev/null" "Saved to file '/dev/null'\\."
+    gdb_test "userdefined" "#0  main ().*"
+    gdb_test "set logging off" "Done logging to /dev/null\\."
+    gdb_test "help" "List of classes of commands:.*"
+    gdb_test_no_output "set logging redirect off"
+}