gpui: Bump taffy to 0.4.3 again (#11655)

We reverted bump to taffy 0.4.3 following an issue spotted by
@maxdeviant where chat text input was not being rendered correctly:

![image](https://github.com/zed-industries/zed/assets/24362066/9d7e6444-47b1-4ac2-808f-bf10404377c0)
This was an issue with the previous attempt to upgrade to taffy 0.4.0 as
well. We bail early in `compute_auto_height_layout` due to a missing
width:
https://github.com/zed-industries/zed/blob/df190ea84621837c44fa50c62837bdbea04b9e22/crates/editor/src/element.rs#L5266
The same issue is visible in story for auto-height editor (or rather,
the breakage is visible - the editor simply does not render at all
there).

I tracked down the breakage to
DioxusLabs/taffy#573 ; it looks like it
specifically affects editors with auto-height. In taffy <0.4 which we
were using previously, we'd eventually get a proper width for
auto-height EditorElement after having initially computed the size. With
taffy 0.4 however (and specifically that PR mentioned earlier), we're
getting `Size::NONE` in layout phase [^1].
I've noticed though that even with taffy <0.3, the
`known_dimensions.width` was always equal to `available_space.width` in
layout phase. Hence, I went with falling back to `available_space.width`
when it is a definite value and we don't have a
`known_dimensions.width`.
Done this way, both chat input and auto-height story render correctly.
/cc @as-cii 
Related:
#11606
#11622
#7868
#7896

[^1]: This could possibly be related to change in what gets passed in
https://github.com/DioxusLabs/taffy/pull/573/files#diff-60c916e9b0c507925f032cecdde6ae163e41b84b8e4bc0a6c04f7d846b0aad9eR133
, though I'm not sure if editor is a leaf node in this case

Release Notes:

- N/A

crates/editor/src/element.rs

@@ -3670,19 +3670,23 @@ impl Element for EditorElement {
                     let editor_handle = cx.view().clone();
                     let max_line_number_width =
                         self.max_line_number_width(&editor.snapshot(cx), cx);
-                    cx.request_measured_layout(Style::default(), move |known_dimensions, _, cx| {
-                        editor_handle
-                            .update(cx, |editor, cx| {
-                                compute_auto_height_layout(
-                                    editor,
-                                    max_lines,
-                                    max_line_number_width,
-                                    known_dimensions,
-                                    cx,
-                                )
-                            })
-                            .unwrap_or_default()
-                    })
+                    cx.request_measured_layout(
+                        Style::default(),
+                        move |known_dimensions, available_space, cx| {
+                            editor_handle
+                                .update(cx, |editor, cx| {
+                                    compute_auto_height_layout(
+                                        editor,
+                                        max_lines,
+                                        max_line_number_width,
+                                        known_dimensions,
+                                        available_space.width,
+                                        cx,
+                                    )
+                                })
+                                .unwrap_or_default()
+                        },
+                    )
                 }
                 EditorMode::Full => {
                     let mut style = Style::default();
@@ -5261,9 +5265,16 @@ fn compute_auto_height_layout(
     max_lines: usize,
     max_line_number_width: Pixels,
     known_dimensions: Size<Option<Pixels>>,
+    available_width: AvailableSpace,
     cx: &mut ViewContext<Editor>,
 ) -> Option<Size<Pixels>> {
-    let width = known_dimensions.width?;
+    let width = known_dimensions.width.or_else(|| {
+        if let AvailableSpace::Definite(available_width) = available_width {
+            Some(available_width)
+        } else {
+            None
+        }
+    })?;
     if let Some(height) = known_dimensions.height {
         return Some(size(width, height));
     }

crates/gpui/Cargo.toml

@@ -61,7 +61,7 @@ slotmap = "1.0.6"
 smallvec.workspace = true
 smol.workspace = true
 sum_tree.workspace = true
-taffy = { git = "https://github.com/DioxusLabs/taffy", rev = "1876f72bee5e376023eaa518aa7b8a34c769bd1b" }
+taffy = "0.4.3"
 thiserror.workspace = true
 time.workspace = true
 util.workspace = true

crates/gpui/src/taffy.rs

@@ -9,14 +9,14 @@ use taffy::{
     geometry::{Point as TaffyPoint, Rect as TaffyRect, Size as TaffySize},
     style::AvailableSpace as TaffyAvailableSpace,
     tree::NodeId,
-    Taffy,
+    TaffyTree, TraversePartialTree as _,
 };
 
 type NodeMeasureFn =
     Box<dyn FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>>;
 
 pub struct TaffyLayoutEngine {
-    taffy: Taffy,
+    taffy: TaffyTree<()>,
     styles: FxHashMap<LayoutId, Style>,
     children_to_parents: FxHashMap<LayoutId, LayoutId>,
     absolute_layout_bounds: FxHashMap<LayoutId, Bounds<Pixels>>,
@@ -29,7 +29,7 @@ static EXPECT_MESSAGE: &str = "we should avoid taffy layout errors by constructi
 impl TaffyLayoutEngine {
     pub fn new() -> Self {
         TaffyLayoutEngine {
-            taffy: Taffy::new(),
+            taffy: TaffyTree::new(),
             styles: FxHashMap::default(),
             children_to_parents: FxHashMap::default(),
             absolute_layout_bounds: FxHashMap::default(),
@@ -114,7 +114,7 @@ impl TaffyLayoutEngine {
     fn max_depth(&self, depth: u32, parent: LayoutId) -> anyhow::Result<u32> {
         println!(
             "{parent:?} at depth {depth} has {} children",
-            self.taffy.child_count(parent.0)?
+            self.taffy.child_count(parent.0)
         );
 
         let mut max_child_depth = 0;