Notify observer of breakpoint auto-disabling

As breakpoint_modified observer is currently notified upon breakpoint stop
before handling auto-disabling when enable count is reached, the observer
is never notified of the disabling.

The problem affects:
- The MI interpreter enabled= value when reporting =breakpoint-modified
- A Python event handler for breakpoint_modified using the "enabled"
  member of its parameter
- insight: breakpoint GUI window is not properly updated upon auto-disable

This patch moves the observer notification after the auto-disabling
code and implements corresponding tests for the MI and Python cases.

Fixes https://sourceware.org/bugzilla/show_bug.cgi?id=23336

Change-Id: I0c50df4789334071e5390cb46b3ca0d4a7f83c61

gdb/breakpoint.c

@@ -5491,7 +5491,6 @@ bpstat_stop_status (const address_space *aspace,
 	  if (bs->stop)
 	    {
 	      ++(b->hit_count);
-	      gdb::observers::breakpoint_modified.notify (b);
 
 	      /* We will stop here.  */
 	      if (b->disposition == disp_disable)
@@ -5501,6 +5500,7 @@ bpstat_stop_status (const address_space *aspace,
 		    b->enable_state = bp_disabled;
 		  removed_any = 1;
 		}
+	      gdb::observers::breakpoint_modified.notify (b);
 	      if (b->silent)
 		bs->print = 0;
 	      bs->commands = b->commands;

gdb/testsuite/gdb.mi/mi-breakpoint-changed.exp

@@ -257,3 +257,44 @@ proc test_pending_resolved { } {
 with_test_prefix "test_pending_resolved" {
     test_pending_resolved
 }
+
+# Test auto-disable is effective when notifying breakpoint-modified.
+
+proc test_auto_disable { } {
+    global mi_gdb_prompt
+    global lib_sl1 lib_sl2
+    global binfile
+
+    mi_clean_restart $binfile
+
+    mi_load_shlibs $lib_sl1 $lib_sl2
+
+    mi_runto_main
+
+    # Set the breakpoint.
+    mi_gdb_test "-break-insert -f pendfunc1" \
+	{(&.*)*.*~"Breakpoint 2 at.*\\n".*=breakpoint-created,bkpt=\{number="2",type="breakpoint".*\}.*\n\^done}
+
+    # Enable for one shot only.
+    mi_gdb_test "-break-enable count 1 2" \
+	{=breakpoint-modified,bkpt=\{number="2",type="breakpoint",disp="dis",enabled="y".*\}.*\n\^done}
+
+    mi_send_resuming_command "exec-continue" "continuing execution to breakpoint"
+
+    set test "breakpoint auto-disabling after enable count reached"
+    gdb_expect {
+	-re ".*=breakpoint-modified,bkpt=\{number=\"2\".*enabled=\"n\"" {
+	    pass $test
+	}
+	-re ".*${mi_gdb_prompt}$" {
+	    fail $test
+	}
+	timeout {
+	    fail "$test (timeout)"
+	}
+    }
+}
+
+with_test_prefix "test_auto_disable" {
+    test_auto_disable
+}

gdb/testsuite/gdb.python/py-breakpoint.exp

@@ -799,6 +799,28 @@ proc_with_prefix test_catchpoints {} {
     gdb_test "continue" "Stopped at catchpoint event: ${num}"
 }
 
+# Test auto-disable is effective when notifying breakpoint_modified.
+
+proc_with_prefix test_bkpt_auto_disable { } {
+    global srcfile testfile hex decimal
+
+    # Start with a fresh gdb.
+    clean_restart ${testfile}
+
+    if ![runto_main] then {
+	fail "cannot run to main."
+	return 0
+    }
+    delete_breakpoints
+
+    set mult_line [gdb_get_line_number "Break at multiply."]
+    gdb_breakpoint ${mult_line}
+    gdb_test_no_output "enable count 1 2" "one shot enable"
+    gdb_test_no_output "python gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))" \
+	"trap breakpoint_modified event"
+    gdb_test "continue" "False.*" "auto-disabling after enable count reached"
+}
+
 test_bkpt_basic
 test_bkpt_deletion
 test_bkpt_cond_and_cmds
@@ -815,3 +837,4 @@ test_bkpt_events
 test_bkpt_explicit_loc
 test_bkpt_qualified
 test_bkpt_probe
+test_bkpt_auto_disable