Merge patch series "add [ as alias for test, fix 0/1 argument handling"

Rasmus Villemoes <ravi@prevas.dk> says:

Make 'test' behave a little more like its cousins in other shells, by
allowing the [ ... ] spelling, and while here, fix up the handling of
a single, non-empty argument to comply with POSIX.

Link: https://lore.kernel.org/r/20260312100106.702368-1-ravi@prevas.dk

cmd/test.c

@@ -63,10 +63,25 @@ static int do_test(struct cmd_tbl *cmdtp, int flag, int argc,
 	char * const *ap;
 	int i, op, left, adv, expr, last_expr, last_unop, last_binop;
 
-	/* args? */
-	if (argc < 3)
+	if (!strcmp(argv[0], "[")) {
+		if (strcmp(argv[argc - 1], "]")) {
+			printf("[: missing terminating ]\n");
+			return 1;
+		}
+		argc--;
+	}
+
+	/*
+	 * Per POSIX, 'test' with 0 arguments should return 1, while
+	 * 'test <arg>' should be equivalent to 'test -n <arg>',
+	 * i.e. true if and only if <arg> is not empty.
+	 */
+	if (argc < 2)
 		return 1;
 
+	if (argc == 2)
+		return !strcmp(argv[1], "");
+
 #ifdef DEBUG
 	{
 		debug("test(%d):", argc);
@@ -212,6 +227,17 @@ U_BOOT_CMD(
 	"[args..]"
 );
 
+/*
+ * This does not use the U_BOOT_CMD macro as [ can't be used in symbol names
+ */
+ll_entry_declare(struct cmd_tbl, lbracket, cmd) = {
+	"[",	CONFIG_SYS_MAXARGS, cmd_always_repeatable, do_test,
+	"alias for 'test'",
+#ifdef CONFIG_SYS_LONGHELP
+	" <test expression> ]"
+#endif /* CONFIG_SYS_LONGHELP */
+};
+
 static int do_false(struct cmd_tbl *cmdtp, int flag, int argc,
 		    char *const argv[])
 {

doc/usage/cmd/test.rst

@@ -20,11 +20,14 @@ Synopsis
     test -e <interface> <dev[:part]> <path>
     test <s> =~ <re>
 
+    [ <test expression> ]
+
 Description
 -----------
 
 The ``test`` command is similar to the ordinary shell built-in by the
-same name. Unlike in ordinary shells, it cannot be spelled ``[``.
+same name. Like in ordinary shells, it can also be spelled ``[``,
+provided the test expression is followed by a separate ``]`` argument.
 
 Strings
 ~~~~~~~

test/hush/if.c

@@ -32,6 +32,15 @@ static int hush_test_if_base(struct unit_test_state *uts)
 	sprintf(if_formatted, if_format, "false");
 	ut_asserteq(1, run_command(if_formatted, 0));
 
+	sprintf(if_formatted, if_format, "test");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "test ''");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "test 'abc'");
+	ut_assertok(run_command(if_formatted, 0));
+
 	return 0;
 }
 HUSH_TEST(hush_test_if_base, 0);
@@ -315,3 +324,67 @@ static int hush_test_if_z_operator(struct unit_test_state *uts)
 	return 0;
 }
 HUSH_TEST(hush_test_if_z_operator, 0);
+
+static int hush_test_lbracket_alias(struct unit_test_state *uts)
+{
+	char if_formatted[128];
+	const char *missing_rbracket_error = "[: missing terminating ]";
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = aaa]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa = bbb]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ aaa != aaa -o bbb != bbb ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ aaa != aaa -o bbb = bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ! aaa != aaa -o ! bbb != bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ! aaa != aaa -o ! bbb = bbb ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ '' ]");
+	ut_asserteq(1, run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ ''");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	sprintf(if_formatted, if_format, "[ 'abc' ]");
+	ut_assertok(run_command(if_formatted, 0));
+
+	sprintf(if_formatted, if_format, "[ 'abc'");
+	ut_asserteq(1, run_command(if_formatted, 0));
+	ut_assert_nextline(missing_rbracket_error);
+
+	return 0;
+}
+HUSH_TEST(hush_test_lbracket_alias, UTF_CONSOLE);