# Description
Instead of handling a foreground process being stopped in any way, we
were simply ignoring SIGTSTP (which the terminal usually sends to the
foreground process group when Ctrl-Z is pressed), and propagating this
to our foreground children. This works for most processes, but it
generally fails for applications which put the terminal in raw mode[1]
and implement their own suspension mechanism (typically TUI apps like
helix[2], neovim[3], top[4] or amp[5]). In these cases, triggering
suspension within the app results in the terminal getting blocked, since
the application is waiting for a SIGCONT, while nushell is waiting for
it to exit.
Fix this by unblocking SIGTSTP for our foreground children (neovim,
helix and probably others send this to themselves while trying to
suspend), and displaying the following message whenever one of them gets
stopped:
nushell currently does not support background jobs
press any key to continue
Pressing any key will then send SIGCONT to the child's process group and
resume waiting.
This fix is probably going to be superseded by a proper background job
implementation (#247) at some point, but for now it's better than
completely blocking the terminal.
[1]
https://docs.rs/crossterm/latest/crossterm/terminal/index.html#raw-mode
[2] https://helix-editor.com/
[3] https://neovim.io/
[4] https://man7.org/linux/man-pages/man1/top.1.html
[5] https://amp.rs/
- fixes#1038
- fixes#7335
- fixes#10335
# User-Facing Changes
While any foreground process is running, Ctrl-Z is no longer ignored.
Instead, the message described above is displayed, and nushell waits for
a key to be pressed.
# Tests + Formatting
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> **Note**
> from `nushell` you can also use the `toolkit` as follows
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# After Submitting
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# Description
This PR introduces a `ByteStream` type which is a `Read`-able stream of
bytes. Internally, it has an enum over three different byte stream
sources:
```rust
pub enum ByteStreamSource {
Read(Box<dyn Read + Send + 'static>),
File(File),
Child(ChildProcess),
}
```
This is in comparison to the current `RawStream` type, which is an
`Iterator<Item = Vec<u8>>` and has to allocate for each read chunk.
Currently, `PipelineData::ExternalStream` serves a weird dual role where
it is either external command output or a wrapper around `RawStream`.
`ByteStream` makes this distinction more clear (via `ByteStreamSource`)
and replaces `PipelineData::ExternalStream` in this PR:
```rust
pub enum PipelineData {
Empty,
Value(Value, Option<PipelineMetadata>),
ListStream(ListStream, Option<PipelineMetadata>),
ByteStream(ByteStream, Option<PipelineMetadata>),
}
```
The PR is relatively large, but a decent amount of it is just repetitive
changes.
This PR fixes#7017, fixes#10763, and fixes#12369.
This PR also improves performance when piping external commands. Nushell
should, in most cases, have competitive pipeline throughput compared to,
e.g., bash.
| Command | Before (MB/s) | After (MB/s) | Bash (MB/s) |
| -------------------------------------------------- | -------------:|
------------:| -----------:|
| `throughput \| rg 'x'` | 3059 | 3744 | 3739 |
| `throughput \| nu --testbin relay o> /dev/null` | 3508 | 8087 | 8136 |
# User-Facing Changes
- This is a breaking change for the plugin communication protocol,
because the `ExternalStreamInfo` was replaced with `ByteStreamInfo`.
Plugins now only have to deal with a single input stream, as opposed to
the previous three streams: stdout, stderr, and exit code.
- The output of `describe` has been changed for external/byte streams.
- Temporary breaking change: `bytes starts-with` no longer works with
byte streams. This is to keep the PR smaller, and `bytes ends-with`
already does not work on byte streams.
- If a process core dumped, then instead of having a `Value::Error` in
the `exit_code` column of the output returned from `complete`, it now is
a `Value::Int` with the negation of the signal number.
# After Submitting
- Update docs and book as necessary
- Release notes (e.g., plugin protocol changes)
- Adapt/convert commands to work with byte streams (high priority is
`str length`, `bytes starts-with`, and maybe `bytes ends-with`).
- Refactor the `tee` code, Devyn has already done some work on this.
---------
Co-authored-by: Devyn Cairns <devyn.cairns@gmail.com>
