Fix "set integer-command unlimited junk"

With integer commands that support "unlimited", we currently fail to
notice junk after "unlimited":

 (gdb) show print elements
 Limit on string chars or array elements to print is 200.
 (gdb) set print elements unlimited foo
 (gdb) show print elements
 Limit on string chars or array elements to print is unlimited.

This commit fixes that.  After, we get:

 (gdb) set print elements unlimited foo
 Junk after "unlimited": foo

gdb/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* cli/cli-setshow.c (cli/cli-setshow.c): New parameter
	'expression'.  When parsing an expression, error out if there's
	junk after "unlimited".
	(parse_cli_var_uinteger, parse_cli_var_zuinteger_unlimited)
	(do_set_command): Adjust calls to is_unlimited_literal.

gdb/testsuite/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* gdb.base/settings.exp (test-integer): Test junk after
	"unlimited".

1 files changed, 19 insertions, 4 deletions

diff --git a/gdb/cli/cli-setshow.c b/gdb/cli/cli-setshow.c
index 14ea723..8199fa7 100644
--- a/gdb/cli/cli-setshow.c
+++ b/gdb/cli/cli-setshow.c
@@ -150,10 +150,12 @@ deprecated_show_value_hack (struct ui_file *ignore_file,
 /* Returns true if ARG is "unlimited".  */
 
 static bool
-is_unlimited_literal (const char **arg)
+is_unlimited_literal (const char **arg, bool expression)
 {
   *arg = skip_spaces (*arg);
 
+  const char *unl_start = *arg;
+
   const char *p = skip_to_space (*arg);
 
   size_t len = p - *arg;
@@ -161,6 +163,19 @@ is_unlimited_literal (const char **arg)
   if (len > 0 && strncmp ("unlimited", *arg, len) == 0)
     {
       *arg += len;
+
+      /* If parsing an expression (i.e., parsing for a "set" command),
+	 anything after "unlimited" is junk.  For options, anything
+	 after "unlimited" might be a command argument or another
+	 option.  */
+      if (expression)
+	{
+	  const char *after = skip_spaces (*arg);
+	  if (*after != '\0')
+	    error (_("Junk after \"%.*s\": %s"),
+		   (int) len, unl_start, after);
+	}
+
       return true;
     }
 
@@ -183,7 +198,7 @@ parse_cli_var_uinteger (var_types var_type, const char **arg,
 	error_no_arg (_("integer to set it to."));
     }
 
-  if (var_type == var_uinteger && is_unlimited_literal (arg))
+  if (var_type == var_uinteger && is_unlimited_literal (arg, expression))
     val = 0;
   else if (expression)
     val = parse_and_eval_long (*arg);
@@ -213,7 +228,7 @@ parse_cli_var_zuinteger_unlimited (const char **arg, bool expression)
   if (*arg == nullptr)
     error_no_arg (_("integer to set it to, or \"unlimited\"."));
 
-  if (is_unlimited_literal (arg))
+  if (is_unlimited_literal (arg, expression))
     val = -1;
   else if (expression)
     val = parse_and_eval_long (*arg);
@@ -448,7 +463,7 @@ do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	      error_no_arg (_("integer to set it to."));
 	  }
 
-	if (c->var_type == var_integer && is_unlimited_literal (&arg))
+	if (c->var_type == var_integer && is_unlimited_literal (&arg, true))
 	  val = 0;
 	else
 	  val = parse_and_eval_long (arg);