regression: bat fails to page - will not read from stdin if no file (or -) specified

[jamesodhunt]

bat (no longer) reads from stdin if no file or - is specified. This breaks my git(1) workflow.

What steps will reproduce the bug?

# Works
$ bat big-file.txt

# Fails to page
$ cat big-file.txt | bat

# Fails to page
$ cat big-file.txt | bat -

# Works (because an actual file is specified)
$ cat big-file.txt | bat /dev/fd/0

What happens?

bat doesn't page - the file is just dumped to stdout a la cat(1).

What did you expect to happen instead?

bat should page the file.

How did you install bat?

$ git clone https://github.com/sharkdp/bat
$ cargo install --path .

---

$ bat --version
bat 0.23.0 (b420c42)

[jamesodhunt]

I'm afraid I don't have time to debug the problem but the code in this block looks odd and potentially related:

• https://github.com/sharkdp/bat/blob/master/src/bin/bat/app.rs#L311..L324

It looks like files being None is handled twice: once on line 311 and again on 318, but presumably we can't get to that line?

[Nigecat]

This caused some problems for me as well, a quick bisection shows that the regression was introduced in 57cc0d8 when atty was switched to is-terminal.

This seems to have been introduced since the condition !atty::is(Stream::Stdin) was inverted to std::io::stdin().is_terminal(). This seems to be a mistake since the comment says

// If we are reading from stdin, only enable paging if we write to an
// interactive terminal and if we do not *read* from an interactive
// terminal.

but the current code enables paging if stdin is interactive.