[2/5] gdb: make set/show args work with $_gdb_setting_str

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index dd5808b17e7..2f0d4f38c85 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -66,14 +66,6 @@  static void step_1 (int, int, const char *);
 #define ERROR_NO_INFERIOR \
    if (!target_has_execution ()) error (_("The program is not being run."));
 
-/* Scratch area where string containing arguments to give to the
-   program will be stored by 'set args'.  As soon as anything is
-   stored, notice_args_set will move it into per-inferior storage.
-   Arguments are separated by spaces.  Empty string (pointer to '\0')
-   means no args.  */
-
-static std::string inferior_args_scratch;
-
 /* Scratch area where the new cwd will be stored by 'set cwd'.  */
 
 static std::string inferior_cwd_scratch;
@@ -136,26 +128,33 @@  set_inferior_args_vector (int argc, char **argv)
   current_inferior ()->set_args (std::move (n));
 }
 
-/* Notice when `set args' is run.  */
+/* Store the new value passed to 'set args'.  */
 
 static void
-set_args_command (const char *args, int from_tty, struct cmd_list_element *c)
+set_args_value (const std::string &args)
 {
-  /* CLI has assigned the user-provided value to inferior_args_scratch.
-     Now route it to current inferior.  */
-  current_inferior ()->set_args (inferior_args_scratch);
+  current_inferior ()->set_args (args);
 }
 
-/* Notice when `show args' is run.  */
+/* Return the value for 'show args' to display.  */
+
+static const std::string &
+get_args_value ()
+{
+  return current_inferior ()->args ();
+}
+
+/* Callback to implement 'show args' command.  */
 
 static void
 show_args_command (struct ui_file *file, int from_tty,
 		   struct cmd_list_element *c, const char *value)
 {
-  /* Note that we ignore the passed-in value in favor of computing it
-     directly.  */
-  deprecated_show_value_hack (file, from_tty, c,
-			      current_inferior ()->args ().c_str ());
+  /* Ignore the passed in value, pull the argument directly from the
+     inferior.  However, these should always be the same.  */
+  gdb_printf (_("\
+Argument list to give program being debugged when it is started is \"%s\".\n"),
+	      current_inferior ()->args ().c_str ());
 }
 
 /* See gdbsupport/common-inferior.h.  */
@@ -3154,12 +3153,12 @@  is restored."),
   add_alias_cmd ("tty", tty_set_show.set, class_run, 0, &cmdlist);
 
   auto args_set_show
-    = add_setshow_string_noescape_cmd ("args", class_run,
-				       &inferior_args_scratch, _("\
+    = add_setshow_string_noescape_cmd ("args", class_run, _("\
 Set argument list to give program being debugged when it is started."), _("\
 Show argument list to give program being debugged when it is started."), _("\
 Follow this command with any number of args, to be passed to the program."),
-				       set_args_command,
+				       set_args_value,
+				       get_args_value,
 				       show_args_command,
 				       &setlist, &showlist);
   set_cmd_completer (args_set_show.set, filename_completer);
diff --git a/gdb/testsuite/gdb.multi/gdb-settings.c b/gdb/testsuite/gdb.multi/gdb-settings.c
new file mode 100644
index 00000000000..3a264f239ed
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/gdb-settings.c
@@ -0,0 +1,22 @@ 
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 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/>.  */
+
+int
+main ()
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.multi/gdb-settings.exp b/gdb/testsuite/gdb.multi/gdb-settings.exp
new file mode 100644
index 00000000000..d2741d16157
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/gdb-settings.exp
@@ -0,0 +1,98 @@ 
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 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/>.
+
+# Test the use of $_gdb_setting_str with multiple inferiors.  Mostly
+# this test is interested in checking that per-inferior settings work
+# correctly.
+
+standard_testfile
+
+require !use_gdb_stub
+
+if {[build_executable "failed to prepare" $testfile $srcfile]} {
+    return -1
+}
+
+# Return a string containing the args to pass to inferior NUM.
+
+proc inferior_args {num} {
+    return "a_${num}_1 a_${num}_2 a_${num}_3"
+}
+
+# Start inferior NUM.
+
+proc start_inferior {num} {
+    with_test_prefix "start_inferior $num" {
+	global srcfile binfile
+
+	set args [inferior_args ${num}]
+
+	if {$num != 1} {
+	    gdb_test "add-inferior" "Added inferior $num.*" \
+		"add empty inferior"
+	    gdb_test "inferior $num" "Switching to inferior $num.*" \
+		"switch to inferior"
+
+	    gdb_test_no_output "set args $args"
+	}
+
+	gdb_test {print $_gdb_setting_str("args")} \
+	    " = \"$args\"" \
+	    "check args before loading a file"
+
+	gdb_load $binfile
+
+	if {[gdb_start_cmd] < 0} {
+	    fail "could not start"
+	    return -1
+	}
+	gdb_test "" ".*reakpoint .*, main .*${srcfile}.*" "start"
+
+	gdb_test {print $_gdb_setting_str("args")} \
+	    " = \"$args\"" \
+	    "check after after starting"
+    }
+
+    return 0
+}
+
+# For the first inferior we set the arguments on the command line.
+save_vars { GDBFLAGS } {
+    set args [inferior_args 1]
+    append GDBFLAGS " --args ${binfile} $args"
+    clean_restart
+}
+
+# An arbitrary number of inferiors to start.
+set NUM_INFS 3
+
+# Start each inferior, setting (and checking) its args as we do.
+for {set i 1} {$i <= $NUM_INFS} {incr i} {
+    if {[start_inferior $i] < 0} {
+	return -1
+    }
+}
+
+# Switch back to each inferior and check the args are correct.
+for {set i 1} {$i <= $NUM_INFS} {incr i} {
+    gdb_test "inferior $i" "Switching to inferior $i .*"
+
+    set args [inferior_args $i]
+    gdb_test {print $_gdb_setting_str("args")} \
+	" = \"$args\"" \
+	"check args after after switching to inferior $i"
+}