Description of problem:

`bash -t` does not work on RHEL8.
It works on RHEL7 and earlier, and on RHEL9.

[root@rhel87 ~]# rpm -q bash
bash-4.4.20-4.el8_6.x86_64
[root@rhel87 ~]# bash -t <<< "echo hello"
[root@rhel87 ~]#

[root@rhel79 ~]# rpm -q bash
bash-4.2.46-34.el7.x86_64
[root@rhel79 ~]# bash -t <<< "echo hello"
hello
[root@rhel79 ~]#

[root@rhel92 ~]# rpm -q bash
bash-5.1.8-6.el9_1.x86_64
[root@rhel92 ~]# bash -t <<< "echo hello"
hello
[root@rhel92 ~]#

Version-Release number of selected component (if applicable):

• Red Hat Enterprise Linux 8
• bash-4.4.20-4.el8_6

How reproducible:

Always

Steps to Reproduce:
1. Run `bash -t <<< "echo hello"`

Actual results:

Nothing is displayed and sub-shell exits immediately.

Expected results:

"hello" will be displayed.

Additional info:

It seems to be a problem with the handling of tokens in the input.
In upstream, the following commit solved the problem.

--------------------------------------------------------------------
commit d233b485e83c3a784b803fb894280773f16f2deb (tag: bash-5.0)
Author: Chet Ramey <chet.ramey@case.edu>
Date: Mon Jan 7 09:27:52 2019 -0500

bash-5.0 distribution sources and documentation
:
+eval.c
+ - reader_loop: if we're just going to execute one command, make sure
+ the read-ahead token isn't set to something that will result in a
+ NULL command (by calling reset_readahead_token), since the code
+ will take that as the one command and set EOF_Reached
--------------------------------------------------------------------

It can be fixed by adding the following code extracted from bash-5.0.

--------------------------------------------------------------------

1. cat bash-4.4-fix.patch
   • • a/eval.c 2023-08-25 11:35:52.304318084 +0900
       +++ b/eval.c 2023-08-25 11:37:12.593570384 +0900
       @@ -79,6 +79,9 @@ reader_loop ()

our_indirection_level = ++indirection_level;

+ if (just_one_command)
+ reset_readahead_token ();
+
while (EOF_Reached == 0)

{ int code; --- a/parse.y 2023-08-25 11:35:52.349318785 +0900 +++ b/parse.y 2023-08-25 11:38:06.863417857 +0900 @@ -4683,6 +4683,13 @@ token_is_ident (t, i) }

#endif

+void
+reset_readahead_token ()
+

{ + if (token_to_read == '\n') + token_to_read = 0; +}

+
static int
read_token_word (character)
int character;
--------------------------------------------------------------------