This PR will close#13501
# Description
This PR expands on [the relay of signals to running plugin
processes](https://github.com/nushell/nushell/pull/13181). The Ctrlc
relay has been generalized to SignalAction::Interrupt and when
reset_signal is called on the main EngineState, a SignalAction::Reset is
now relayed to running plugins.
# User-Facing Changes
The signal handler closure now takes a `signals::SignalAction`, while
previously it took no arguments. The handler will now be called on both
interrupt and reset. The method to register a handler on the plugin side
is now called `register_signal_handler` instead of
`register_ctrlc_handler`
[example](https://github.com/nushell/nushell/pull/13510/files#diff-3e04dff88fd0780a49778a3d1eede092ec729a1264b4ef07ca0d2baa859dad05L38).
This will only affect plugin authors who have started making use of
https://github.com/nushell/nushell/pull/13181, which isn't currently
part of an official release.
The change will also require all of user's plugins to be recompiled in
order that they don't error when a signal is received on the
PluginInterface.
# Testing
```
: example ctrlc
interrupt status: false
waiting for interrupt signal...
^Cinterrupt status: true
peace.
Error: × Operation interrupted
╭─[display_output hook:1:1]
1 │ if (term size).columns >= 100 { table -e } else { table }
· ─┬
· ╰── This operation was interrupted
╰────
: example ctrlc
interrupt status: false <-- NOTE status is false
waiting for interrupt signal...
^Cinterrupt status: true
peace.
Error: × Operation interrupted
╭─[display_output hook:1:1]
1 │ if (term size).columns >= 100 { table -e } else { table }
· ─┬
· ╰── This operation was interrupted
╰────
```
# Description
This PR adds a new method to `EngineInterface`: `register_ctrlc_handler`
which takes a closure to run when the plugin's driving engine receives a
ctrlc-signal. It also adds a mirror of the `signals` attribute from the
main shell `EngineState`.
This is an example of how a plugin which makes a long poll http request
can end the request on ctrlc:
https://github.com/cablehead/nu_plugin_http/blob/main/src/commands/request.rs#L68-L77
To facilitate the feature, a new attribute has been added to
`EngineState`: `ctrlc_handlers`. This is a Vec of closures that will be
run when the engine's process receives a ctrlc signal.
When plugins are added to an `engine_state` during a `merge_delta`, the
engine passes the ctrlc_handlers to the plugin's
`.configure_ctrlc_handler` method, which gives the plugin a chance to
register a handler that sends a ctrlc packet through the
`PluginInterface`, if an instance of the plugin is currently running.
On the plugin side: `EngineInterface` also has a ctrlc_handlers Vec of
closures. Plugin calls can use `register_ctrlc_handler` to register a
closure that will be called in the plugin process when the
PluginInput::Ctrlc command is received.
For future reference these are some alternate places that were
investigated for tying the ctrlc trigger to transmitting a Ctrlc packet
through the `PluginInterface`:
- Directly from `src/signals.rs`: the handler there would need a
reference to the Vec<Arc<RegisteredPlugins>>, which would require us to
wrap the plugins in a Mutex, which we don't want to do.
- have `PersistentPlugin.get_plugin` pass down the engine's
CtrlcHandlers to .get and then to .spawn (if the plugin isn't already
running). Once we have CtrlcHandlers in spawn, we can register a handler
to write directly to PluginInterface. We don't want to double down on
passing engine_state to spawn this way though, as it's unpredictable
because it would depend on whether the plugin has already been spawned
or not.
- pass `ctrlc_handlers` to PersistentPlugin::new so it can store it on
itself so it's available to spawn.
- in `PersistentPlugin.spawn`, create a handler that sends to a clone of
the GC event loop's tx. this has the same issues with regards to how to
get CtrlcHandlers to the spawn method, and is more complicated than a
handler that writes directly to PluginInterface
# User-Facing Changes
No breaking changes
---------
Co-authored-by: Ian Manske <ian.manske@pm.me>
# Description
This PR introduces a new `Signals` struct to replace our adhoc passing
around of `ctrlc: Option<Arc<AtomicBool>>`. Doing so has a few benefits:
- We can better enforce when/where resetting or triggering an interrupt
is allowed.
- Consolidates `nu_utils::ctrl_c::was_pressed` and other ad-hoc
re-implementations into a single place: `Signals::check`.
- This allows us to add other types of signals later if we want. E.g.,
exiting or suspension.
- Similarly, we can more easily change the underlying implementation if
we need to in the future.
- Places that used to have a `ctrlc` of `None` now use
`Signals::empty()`, so we can double check these usages for correctness
in the future.
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
# Description
Simplifies `SIGQUIT` protection to a single `signal` ignore system call.
# User-Facing Changes
`SIGQUIT` is no longer blocked if nushell is in non-interactive mode
(signals should not be blocked in non-interactive mode).
Also a breaking API change for `nu_protocol`.
# Tests + Formatting
Should come after #11178 for testing.
