Re: Tab completion regression test failed on illumos

On Thu, 02 Nov 2023 at 22:23, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Japin Li <japinli@hotmail.com> writes:
>> It seems the 'SEL\t' is converted to 'SEL     ' which is "SEL" with 5 spaces.
>
> That would be plausible if readline were disabled, or otherwise
> not functioning.
>

I think this might be a bug comes from Illumos pseudo-tty. I can reproduce
this by using pseudo-tty on Illumos.

Here is a simple test case:

$ cat pseudo-tty.c
#define _XOPEN_SOURCE 600

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>

#define DEV_PTMX        "/dev/ptmx"

int
main(void)
{
    int ptm_fd;
    pid_t pid;
    char *pts_name;

    ptm_fd = open(DEV_PTMX, O_RDWR);
    grantpt(ptm_fd);
    unlockpt(ptm_fd);
    pts_name = ptsname(ptm_fd);

    pid = fork();
    if (pid == -1) {
        fprintf(stderr, "could not fork a new process: %m\n");
        close(ptm_fd);
        return -1;
    } else if (pid == 0) {
        int pts_fd;

        close(ptm_fd);
        pts_fd = open(pts_name, O_RDWR);
        write(pts_fd, "SEL\tH", 5);
        close(pts_fd);
    } else {
        int status;
        char buffer[512] = { 0 };
        ssize_t bytes;

        bytes = read(ptm_fd, buffer, sizeof(buffer));
        printf("%ld: '%s'\n", bytes, buffer);
        waitpid(pid, &status, 0);
        close(ptm_fd);
    }

    return 0;
}

On IllumsOS
$ gcc -o pseudo-tty pseudo-tty.c
$ ./pseudo-tty
9: 'SEL     H'

On Ubuntu
$ gcc -o pseudo-tty pseudo-tty.c
$ ./pseudo-tty
5: 'SEL    H'

--
Regrads,
Japin Li
ChengDu WenWu Information Technology Co., Ltd.