Make cursor_shape optional

[nibon7]

Description

There are several cursor shape related issues #7151 #9243 #7271 #8452 #10169, you can't disable the cursor shape feature even if you comment out the entire cursor_shape block in the config.nu, and even worse, when nushell exits with an error, the cursor shape can't be restored, that is annoying.

This PR provides an opportunity to disable setting the cursor shape.

User-Facing Changes

If you use the default config.nu, nothing changes, but if you comment out cursor_shape block or set them to inherit, related cursor shape will not be set.

Tests + Formatting

After Submitting

[fdncred]

Thanks @nibon7. I'd love to see this work, because you're right, we've had a few complaints about it recently.

It kind of sounds like, if cursor shape is commented it, it "inherts" whatever cursor shape you already have. Is that right? If so, I'm wondering if inherit should be an option too and it just sets the cursor to None?

[nibon7]

If the cursor_shape block is commented out, the line editor will not set the cursor shape.

see https://github.com/nushell/reedline/blob/409b51784f108d7e1f004dfa2dc11d727c95b6f7/src/painting/painter.rs#L181-L191

[nibon7]

Should we provide an option just like none or something else to skip setting the cursor shape?

cursor_shape: {
    emacs: none
    vi_insert: none
    vi_normal: none
}

[fdncred]

Should we provide an option just like none or something else to skip setting the cursor shape?

That is what I was asking. I originally was going to suggest "none" but then I thought people would think that would mean no cursor would appear, and therefore be confusing, which is why I suggested "inherit". However, if "inhert" is not really what it's doing and doesn't describe it well enough, I'm up for other terminology.

[nibon7]

I originally was going to suggest "none" but then I thought people would think that would mean no cursor would appear, and therefore be confusing, which is why I suggested "inherit".

You're absolutely right.

[fdncred]

Thanks @nibon7! Just to be clear, if we set each cursor_shape to inherit, that produces the same behavior as commenting out the entire cursor_shape record. Is that correct?

[nibon7]

Just to be clear, if we set each cursor_shape to inherit, that produces the same behavior as commenting out the entire cursor_shape record. Is that correct?

Yes. If we comment out the cursor_shape record, it will use the default values None, same as inherit.

@@ -156,9 +156,9 @@ impl Default for Config {
             filesize_metric: false,
             filesize_format: "auto".into(),

-            cursor_shape_emacs: NuCursorShape::Line,
-            cursor_shape_vi_insert: NuCursorShape::Block,
-            cursor_shape_vi_normal: NuCursorShape::UnderScore,
+            cursor_shape_emacs: None,
+            cursor_shape_vi_insert: None,
+            cursor_shape_vi_normal: None,

             color_config: HashMap::new(),
             use_grid_icons: true,

[fdncred]

ok, I'm good with this. Thanks @nibon7!!

[mb21]

Good idea! And yes, inherit is definitely better wording that none. I was also thinking of dont-change or keep, as that seems technically a bit more correct – if I understand how the cursor shape works in terminal emulators – it seems to be just a global state that any program can alter.

---

Btw. it could have also been cursor_shape: inherit... but yeah, maybe better keep the config file format synced to the internal Rust sum type, which already can represent nonsensical state like:

edit_mode: emacs,
cursor_shape: {
  vi_insert: line
}

just my two cents ;)