Fix bug in DAP handling of 'pause' requests

While working on cancellation, I noticed that a DAP 'pause' request
would set the "do not emit the continue" flag.  This meant that a
subsequent request that should provoke a 'continue' event would
instead suppress the event.

I then tried writing a more obvious test case for this, involving an
inferior call -- and discovered that gdb.events.cont does not fire for
an inferior call.

This patch installs a new event listener for gdb.events.inferior_call
and arranges for this to emit continue and stop events when
appropriate.  It also fixes the original bug, by adding a check to
exec_and_expect_stop.

(cherry picked from commit c618a1c548193d2a6a8c3d909a3d1c620a156b5d)

2 files changed, 73 insertions, 1 deletions

diff --git a/gdb/testsuite/gdb.dap/pause.c b/gdb/testsuite/gdb.dap/pause.c
new file mode 100644
index 0000000..2395ca6
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/pause.c
@@ -0,0 +1,44 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2011-2023 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <unistd.h>
+
+int
+do_nothing ()
+{
+  return 91;
+}
+
+int
+return_false ()
+{
+  return 0;
+}
+
+void
+sleep_a_bit ()
+{
+  sleep (1);			/* STOP */
+}
+
+int
+main ()
+{
+  while (1)
+    sleep_a_bit ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.dap/pause.exp b/gdb/testsuite/gdb.dap/pause.exp
index 558ede9..30ce609 100644
--- a/gdb/testsuite/gdb.dap/pause.exp
+++ b/gdb/testsuite/gdb.dap/pause.exp
@@ -19,7 +19,7 @@ require allow_dap_tests
 
 load_lib dap-support.exp
 
-standard_testfile attach.c
+standard_testfile
 
 if {[build_executable ${testfile}.exp $testfile $srcfile] == -1} {
     return
@@ -29,6 +29,18 @@ if {[dap_launch $testfile] == ""} {
     return
 }
 
+# Set a conditional breakpoint that will never fire.  This is done to
+# test the state-tracking in events -- an inferior call from a
+# breakpoint condition should not cause any sort of stop or continue
+# events.
+set line [gdb_get_line_number "STOP"]
+dap_check_request_and_response "set conditional breakpoint" \
+    setBreakpoints \
+    [format {o source [o path [%s]] \
+		 breakpoints [a [o line [i %d] \
+				     condition [s "return_false()"]]]} \
+	 [list s $srcfile] $line]
+
 dap_check_request_and_response "start inferior" configurationDone
 dap_wait_for_event_and_check "inferior started" thread "body reason" started
 
@@ -45,4 +57,20 @@ dap_check_request_and_response pause pause \
 dap_wait_for_event_and_check "stopped by pause" stopped \
     "body reason" pause
 
+set result [dap_request_and_response evaluate {o expression [s do_nothing()]}]
+gdb_assert {[dict get [lindex $result 0] body result] == 91} \
+    "check result of evaluation"
+
+set seen fail
+foreach event [lindex $result 1] {
+    if {[dict get $event type] != "event"} {
+	continue
+    }
+    if {[dict get $event event] == "continued"} {
+	set seen pass
+	break
+    }
+}
+gdb_assert {$seen == "pass"} "continue event from inferior call"
+
 dap_shutdown