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Merged
kalenikaliaksandr merged 1 commit into from
Aug 9, 2026
Merged

Make derived baselines an output of formatting context runs #11050

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32 changes: 23 additions & 9 deletions Libraries/LibWeb/Rust/src/layout/flex_formatting_context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,7 @@ struct FlexItem<'pass> {
padding: DirectionAgnosticMargins,
is_min_violation: bool,
is_max_violation: bool,
content_baselines: DerivedBaselines,
}

impl<'pass> FlexItem<'pass> {
Expand Down Expand Up @@ -94,6 +95,7 @@ impl<'pass> FlexItem<'pass> {
padding: DirectionAgnosticMargins::default(),
is_min_violation: false,
is_max_violation: false,
content_baselines: DerivedBaselines::default(),
}
}

Expand Down Expand Up @@ -2295,8 +2297,16 @@ impl<'pass> FlexFormattingContext<'pass> {
}
}

fn box_baseline(&self, node: Node) -> CssPixels {
crate::layout::box_baseline(self.state, &self.callbacks, node, crate::layout::BaselineSet::First)
fn item_box_baseline(&self, index: usize) -> CssPixels {
let item = &self.flex_items[index];
crate::layout::box_baseline_with_content_baselines(
self.state,
&self.callbacks,
item.box_,
item.used_values,
crate::layout::BaselineSet::First,
item.content_baselines,
)
}

// https://drafts.csswg.org/css-flexbox-1/#valdef-align-items-baseline
Expand All @@ -2319,13 +2329,13 @@ impl<'pass> FlexFormattingContext<'pass> {
let mut max_baseline = CssPixels::default();
for index in self.flex_lines[line_index].items.iter().copied() {
if participates(self, index) {
max_baseline = max_baseline.max(self.box_baseline(self.flex_items[index].box_));
max_baseline = max_baseline.max(self.item_box_baseline(index));
}
}
for item_position in 0..self.flex_lines[line_index].items.len() {
let index = self.flex_lines[line_index].items[item_position];
if participates(self, index) {
let baseline = self.box_baseline(self.flex_items[index].box_);
let baseline = self.item_box_baseline(index);
self.flex_items[index].cross_offset += max_baseline - baseline;
}
}
Expand Down Expand Up @@ -2387,11 +2397,15 @@ impl<'pass> FlexFormattingContext<'pass> {
input.sizing.forced_min_border_box_block_size = Some(intrinsic_size + extra);
}

match crate::layout::layout_inside_child(run, None, None, node, LayoutMode::Normal, input, false) {
crate::layout::ChildLayoutOutcome::Created(_) => {}
crate::layout::ChildLayoutOutcome::ReenterCurrent => self.run(run, input),
crate::layout::ChildLayoutOutcome::Skipped => {}
}
self.flex_items[index].content_baselines =
match crate::layout::layout_inside_child(run, None, None, node, LayoutMode::Normal, input, false) {
crate::layout::ChildLayoutOutcome::Created(result) => result.baselines,
crate::layout::ChildLayoutOutcome::ReenterCurrent => {
self.run(run, input);
self.item_used(index).content_baselines_from_cells()
}
crate::layout::ChildLayoutOutcome::Skipped => self.item_used(index).content_baselines_from_cells(),
};

let container_inline_size = self.container_used().content_inline_size.get();
let container_block_size = self.container_used().content_block_size.get();
Expand Down
62 changes: 34 additions & 28 deletions Libraries/LibWeb/Rust/src/layout/formatting_context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -484,12 +484,22 @@ pub(crate) fn box_baseline(
state: &LayoutState,
callbacks: &FfiLayoutFcCallbacks,
box_: Node,
used: &UsedValues,
baseline_set: BaselineSet,
) -> CssPixels {
box_baseline_with_content_baselines(state, callbacks, box_, used, baseline_set, used.content_baselines_from_cells())
}

pub(crate) fn box_baseline_with_content_baselines(
state: &LayoutState,
callbacks: &FfiLayoutFcCallbacks,
box_: Node,
used: &UsedValues,
mut baseline_set: BaselineSet,
content_baselines: DerivedBaselines,
) -> CssPixels {
let facts = state.node_facts(callbacks, box_);
let style = state.style_facts(callbacks, box_);
let used_pointer = state.used_values(callbacks, box_);
let used = used_pointer;
let collapsed = used.uses_collapsing_borders_model.get();

// https://drafts.csswg.org/css2/#propdef-vertical-align
Expand Down Expand Up @@ -559,9 +569,8 @@ pub(crate) fn box_baseline(
let input_derives_from_children = facts.is_html_input_element() && !facts.children_are_inline();

let content_baseline = match baseline_set {
BaselineSet::First if used.has_first_baseline.get() => Some(used.first_baseline.get()),
BaselineSet::Last if used.has_last_baseline.get() => Some(used.last_baseline.get()),
_ => None,
BaselineSet::First => content_baselines.first,
BaselineSet::Last => content_baselines.last,
};
if let Some(content_baseline) = content_baseline
&& (derive_baseline_from_content || input_derives_from_children)
Expand Down Expand Up @@ -630,7 +639,7 @@ pub(crate) fn derive_baselines(
let block_child_state = state.used_values(callbacks, fragment_node);
let child_offset_from_margin_edge = block_child_state.content_offset.get().y
- block_child_state.margin_box_top(block_child_state.uses_collapsing_borders_model.get());
child_offset_from_margin_edge + box_baseline(state, callbacks, fragment_node, baseline_set)
child_offset_from_margin_edge + box_baseline(state, callbacks, fragment_node, block_child_state, baseline_set)
};

let mut first_line_index = 0;
Expand Down Expand Up @@ -706,7 +715,7 @@ pub(crate) fn derive_baselines(
}
let child_offset_from_margin_edge = child_state.content_offset.get().y
- child_state.margin_box_top(child_state.uses_collapsing_borders_model.get());
return Some(child_offset_from_margin_edge + box_baseline(state, callbacks, child, baseline_set));
return Some(child_offset_from_margin_edge + box_baseline(state, callbacks, child, child_state, baseline_set));
}
None
};
Expand Down Expand Up @@ -762,6 +771,7 @@ pub struct FfiBordersData {
pub(crate) struct ChildLayoutResult {
pub automatic_content_inline_size: CssPixels,
pub automatic_content_block_size: CssPixels,
pub baselines: DerivedBaselines,
}

pub(crate) enum ChildLayoutOutcome {
Expand Down Expand Up @@ -1489,57 +1499,53 @@ fn run_formatting_context<'pass>(
None
};
let mut implementation = None;
let result = if let Some(cached_block_size) = cached_atomic_block_size {
let result = if let Some((cached_block_size, cached_baselines)) = cached_atomic_block_size {
ChildLayoutResult {
automatic_content_block_size: cached_block_size,
baselines: cached_baselines,
..ChildLayoutResult::default()
}
} else {
let mut context_implementation = create_formatting_context_implementation(run, parent_grid, fc_type);
let result = match &mut context_implementation {
FormattingContextImplementation::Block(context) => {
context.run(run, body_input);
let result = ChildLayoutResult {
let baselines = context.derived_baselines_of_root_box();
store_derived_baselines(run.state.used_values(&run.callbacks, run.box_), baselines);
ChildLayoutResult {
automatic_content_inline_size: context.automatic_content_inline_size(),
automatic_content_block_size: context.automatic_content_block_size(),
};
store_derived_baselines(
run.state.used_values(&run.callbacks, run.box_),
context.derived_baselines_of_root_box(),
);
result
baselines,
}
}
FormattingContextImplementation::Flex(context) => {
context.run(run, body_input);
store_derived_baselines(
run.state.used_values(&run.callbacks, run.box_),
context.derived_baselines_of_root_box(),
);
let baselines = context.derived_baselines_of_root_box();
store_derived_baselines(run.state.used_values(&run.callbacks, run.box_), baselines);
ChildLayoutResult {
automatic_content_inline_size: context.automatic_content_inline_size(),
automatic_content_block_size: context.automatic_content_block_size(),
baselines,
}
}
FormattingContextImplementation::Grid(context) => {
context.run(run, body_input);
store_derived_baselines(
run.state.used_values(&run.callbacks, run.box_),
context.derived_baselines_of_root_box(),
);
let baselines = context.derived_baselines_of_root_box();
store_derived_baselines(run.state.used_values(&run.callbacks, run.box_), baselines);
ChildLayoutResult {
automatic_content_inline_size: context.automatic_content_inline_size(),
automatic_content_block_size: context.automatic_content_block_size(),
baselines,
}
}
FormattingContextImplementation::Table(context) => {
context.run(run, body_input);
store_derived_baselines(
run.state.used_values(&run.callbacks, run.box_),
context.derived_baselines_of_root_box(),
);
let baselines = context.derived_baselines_of_root_box();
store_derived_baselines(run.state.used_values(&run.callbacks, run.box_), baselines);
ChildLayoutResult {
automatic_content_inline_size: context.automatic_content_inline_size(),
automatic_content_block_size: context.automatic_content_block_size,
baselines,
}
}
FormattingContextImplementation::Svg(context) => {
Expand Down Expand Up @@ -1572,7 +1578,7 @@ fn run_formatting_context<'pass>(
finalize_atomic_root_block_size(
run,
&input,
cached_atomic_block_size,
cached_atomic_block_size.map(|(block_size, _)| block_size),
automatic_content_block_size_of_completed_body_run,
parent_block,
);
Expand Down
32 changes: 18 additions & 14 deletions Libraries/LibWeb/Rust/src/layout/inline_formatting_context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -886,26 +886,28 @@ impl<'context, 'pass> InlineFormattingContext<'context, 'pass> {
next.map(|next| next - containing_block_offset_in_root)
}

fn layout_inside(&mut self, node: Node, available_space: AvailableSpace) {
fn layout_inside(&mut self, node: Node, available_space: AvailableSpace) -> DerivedBaselines {
let input = LayoutInput::new(
available_space,
self.input.containing_block_constraints,
ParticipationInParentFormattingContext::AtomicInline,
);
if let crate::layout::ChildLayoutOutcome::ReenterCurrent = crate::layout::layout_inside_child(
self.run,
Some(self.parent),
None,
node,
self.layout_mode,
input,
false,
) {
self.parent.run(self.run, input);
let content_baselines_from_cells = |used: &UsedValues| DerivedBaselines {
first: used.has_first_baseline.get().then(|| used.first_baseline.get()),
last: used.has_last_baseline.get().then(|| used.last_baseline.get()),
};
match crate::layout::layout_inside_child(self.run, Some(self.parent), None, node, self.layout_mode, input, false)
{
crate::layout::ChildLayoutOutcome::Created(result) => result.baselines,
crate::layout::ChildLayoutOutcome::ReenterCurrent => {
self.parent.run(self.run, input);
content_baselines_from_cells(self.used(node))
}
crate::layout::ChildLayoutOutcome::Skipped => content_baselines_from_cells(self.used(node)),
}
}

pub(crate) fn dimension_box_on_line(&mut self, node: Node) {
pub(crate) fn dimension_box_on_line(&mut self, node: Node) -> DerivedBaselines {
let available_space = self.input.available_space;
let facts = self.facts(node);
// Any fragmented inline box should have generated line box fragments already.
Expand All @@ -918,15 +920,16 @@ impl<'context, 'pass> InlineFormattingContext<'context, 'pass> {
self.callbacks.shell(node),
);
}
return;
return DerivedBaselines::default();
}

self.layout_inside(node, available_space);
let content_baselines = self.layout_inside(node, available_space);
debug_assert!(
self.used(node).has_definite_inline_size.get()
|| self.used(node).inline_size_constraint.get() != SizeConstraint::None,
"atomic inline-level run left its root's inline size unresolved"
);
content_baselines
}

fn clear_floating_boxes(&self, node: Node) -> bool {
Expand Down Expand Up @@ -1021,6 +1024,7 @@ impl<'context, 'pass> InlineFormattingContext<'context, 'pass> {
item.padding_end + item.border_end,
item.margin_start,
item.margin_end,
item.content_baselines,
);
}
ItemType::BlockLevelBox => {
Expand Down
5 changes: 4 additions & 1 deletion Libraries/LibWeb/Rust/src/layout/inline_level_iterator.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ pub(crate) struct Item {
pub(crate) is_collapsible_whitespace: bool,
pub(crate) can_break_before: bool,
pub(crate) preceded_by_unattached_inline_start_edges: bool,
pub(crate) content_baselines: DerivedBaselines,
}

impl Item {
Expand All @@ -51,6 +52,7 @@ impl Item {
is_collapsible_whitespace: false,
can_break_before: false,
preceded_by_unattached_inline_start_edges: false,
content_baselines: DerivedBaselines::default(),
}
}

Expand Down Expand Up @@ -552,8 +554,9 @@ impl<'iterator, 'context, 'pass> InlineLevelIteratorGenerator<'iterator, 'contex
self.context()
.create_used_values(node, self.context().input.containing_block_constraints)
};
self.context_mut().dimension_box_on_line(node);
let content_baselines = self.context_mut().dimension_box_on_line(node);
let mut item = Item::new(ItemType::Element, node);
item.content_baselines = content_baselines;
item.inline_size = used.content_inline_size.get();
item.padding_start = used.padding_left.get();
item.padding_end = used.padding_right.get();
Expand Down
2 changes: 2 additions & 0 deletions Libraries/LibWeb/Rust/src/layout/line_box_fragment.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@ pub(crate) struct LineBoxFragmentData {
pub(crate) first_available_font: *const c_void,
pub(crate) text_utf16: *const u16,
pub(crate) text_length_in_code_units: usize,
pub(crate) content_baselines: Option<DerivedBaselines>,
}

#[derive(Clone, Copy)]
Expand Down Expand Up @@ -103,6 +104,7 @@ impl LineBoxFragmentData {
first_available_font: facts.first_available_font,
text_utf16: facts.text_utf16,
text_length_in_code_units: facts.text_length_in_code_units,
content_baselines: None,
};
if let Some(glyphs) = &fragment.glyphs {
fragment.current_insert_direction = fragment.resolve_glyph_run_direction(glyphs.text_type);
Expand Down
16 changes: 14 additions & 2 deletions Libraries/LibWeb/Rust/src/layout/line_builder.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -216,6 +216,7 @@ impl<'builder, 'context, 'pass> LineBuilder<'builder, 'context, 'pass> {
trailing_size: CssPixels,
leading_margin: CssPixels,
trailing_margin: CssPixels,
content_baselines: DerivedBaselines,
) {
self.prepare_to_append_inline_content();
let used = self.context().used(node);
Expand Down Expand Up @@ -244,6 +245,7 @@ impl<'builder, 'context, 'pass> LineBuilder<'builder, 'context, 'pass> {
fragment_facts,
text_align_is_justify,
);
self.line_mut(line_index).fragments[fragment_index].content_baselines = Some(content_baselines);
self.max_block_size_on_current_line = self.max_block_size_on_current_line.max(margin_block_size);
let used = self.context().used_mut(node);
used.has_containing_line_box_fragment.set(false);
Expand Down Expand Up @@ -557,18 +559,28 @@ impl<'builder, 'context, 'pass> LineBuilder<'builder, 'context, 'pass> {
let mut line_box_baseline = strut_baseline;
let fragment_count = self.line(line_index).fragments.len();
for fragment_index in 0..fragment_count {
let (node, style_source) = {
let (node, style_source, content_baselines) = {
let fragment = &self.line(line_index).fragments[fragment_index];
(fragment.layout_node, fragment.style_source)
(fragment.layout_node, fragment.style_source, fragment.content_baselines)
};
let style = self.context().style(style_source);
let fragment_baseline = if self.context().facts(node).is_text_node() {
Self::baseline_for_style(style, style.line_height())
} else if let Some(content_baselines) = content_baselines {
crate::layout::box_baseline_with_content_baselines(
self.context().state,
&self.context().callbacks,
node,
self.context().used(node),
crate::layout::BaselineSet::Last,
content_baselines,
)
} else {
crate::layout::box_baseline(
self.context().state,
&self.context().callbacks,
node,
self.context().used(node),
crate::layout::BaselineSet::Last,
)
};
Expand Down
1 change: 1 addition & 0 deletions Libraries/LibWeb/Rust/src/layout/replaced_with_children_formatting_context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -69,5 +69,6 @@ fn layout_replaced_with_children(run: &FormattingContextRun, layout_input: Layou
ChildLayoutResult {
automatic_content_inline_size: content_inline_size,
automatic_content_block_size: wrapper_layout.automatic_content_block_size,
baselines: DerivedBaselines::default(),
}
Comment on lines 69 to 73

@coderabbitai coderabbitai Bot Aug 9, 2026

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🗄️ Data Integrity & Integration | 🟠 Major | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Description: Trace whether ReplacedWithChildren roots ever get derived baselines stored
# through a path other than layout_replaced_with_children.
set -euo pipefail

rg -n 'ReplacedWithChildren' Libraries/LibWeb/Rust/src/layout -g '*.rs' -C5

echo '--- is_html_input_element / input_derives_from_children usage ---'
rg -n 'is_html_input_element|input_derives_from_children' Libraries/LibWeb/Rust/src/layout -g '*.rs' -C5

echo '--- finalize_block_level_root definition ---'
rg -n 'fn finalize_block_level_root' Libraries/LibWeb/Rust/src/layout -g '*.rs' -A40

echo '--- store_derived_baselines call sites ---'
rg -n 'store_derived_baselines\(' Libraries/LibWeb/Rust/src/layout -g '*.rs' -B3 -A1

Repository: LadybirdBrowser/ladybird

Length of output: 19900

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo '--- formatting_context.rs baseline functions ---'
sed -n '540,610p' Libraries/LibWeb/Rust/src/layout/formatting_context.rs

echo '--- run_formatting_context relevant section ---'
sed -n '1500,1630p' Libraries/LibWeb/Rust/src/layout/formatting_context.rs

echo '--- replaced_with_children_formatting_context.rs ---'
sed -n '1,130p' Libraries/LibWeb/Rust/src/layout/replaced_with_children_formatting_context.rs

echo '--- all DerivedBaselines default/store/receive occurrences ---'
rg -n 'DerivedBaselines::default|derive_baselines|derived_baselines_of_root_box|content_baselines_from_cells|has_first_baseline|first_baseline|baselines:' Libraries/LibWeb/Rust/src/layout -g '*.rs' -C2

Repository: LadybirdBrowser/ladybird

Length of output: 50380

🏁 Script executed:

#!/bin/bash
set -euo pipefail

python3 - <<'PY'
from pathlib import Path
import re

root = Path("Libraries/LibWeb/Rust/src/layout")

def text(path):
    return path.read_text()

ctx = text(root / "formatting_context.rs")
repr = text(root / "used_values.rs")
bfc = text(root / "block_formatting_context.rs")
replaced = text(root / "replaced_with_children_formatting_context.rs")
inline = text(root / "inline_formatting_context.rs")
flex = text(root / "flex_formatting_context.rs")
grid = text(root / "grid_formatting_context.rs")
table = text(root / "table_formatting_context.rs")

for name, pattern, file in [
    ("derive_baselines", r"pub\(crate\) fn derive_baselines", root/"formatting_context.rs"),
    ("FinalizeAtomicRootBlock", r"fn finalize_atomic_root_block_size", root/"formatting_context.rs"),
    ("compute_and_store_baselines Call", r"self\.compute_and_store_baselines\s*\(", root/"block_formatting_context.rs"),
    ("DeriveBaselines Call", r"crate::layout::derive_baselines\s*\(", file),
]:
    idx = file.find(pattern)
    print(f"--- {name}: {file} ---")
    if idx == -1:
        print("not found")
        continue
    start = file.rfind("\n", 0, max(0, idx - 1000)) + 1
    end = min(idx + 2500, len(file))
    print(file[start:end])

# Read-only invariants focused on the baseline storage data flow.
print("--- invariants ---")

# In run_formatting_context ReplacedWithChildren branch, the result is returned directly and
# the only post-run block-level finalize is finalize_block_level_root().
rf = ctx.find("FormattingContextImplementation::ReplacedWithChildren => layout_replaced_with_children(run, body_input),")
final = ctx.find("fn finalize_block_level_root(", rf)
print(f"run_formatting_context ReplacedWithChildren returns before finalize_block_level_root after child layout: {0 < rf < final}")

# Locate finalize_block_level_root and check it does not call store_derived_baselines.
start = ctx.find("fn finalize_block_level_root(")
end = ctx.find("\nfn size_skipped_independent_root", start)
frag = ctx[start:end]
print(f"finalize_block_level_root calls store_derived_baselines: {'store_derived_baselines(' in frag}")
print(f"finalize_block_level_root records_replaced_block_size: {'record_replaced_block_size(' in frag}")

# Locate derive_baselines and check ReplacedWithChildren children are never treated as derived baselines.
start = ctx.find("// pub(crate) fn derive_baselines", None if "pub(crate) fn derive_baselines" not in ctx else None)
start = ctx.find("pub(crate) fn derive_baselines")
end = ctx.find("pub(crate) struct ChildLayoutResult", start)
ds = ctx[start:end]
print(f"derive_baselines handles child formatting-context boxes: {'is_flex_container' in ds or 'GridFormattingContext' in ds or 'TableFormattingContext' in ds or 'block_container' in ds}")
print(f"derivation first baseline source line count around child-derived baselines:")
for m in re.finditer(r"(has_first_baseline|first_baseline|children_are_inline|BlockFormattingContext)", ds):
    line = ds[:m.start()].count("\n") + 1
    print(f"  line {line}: {m.group()}")
PY

Repository: LadybirdBrowser/ladybird

Length of output: 274

🏁 Script executed:

#!/bin/bash
set -euo pipefail

python3 - <<'PY'
from pathlib import Path
import re

root = Path("Libraries/LibWeb/Rust/src/layout")

def text(path):
    return path.read_text()

ctx = text(root / "formatting_context.rs")
repr = text(root / "used_values.rs")
bfc = text(root / "block_formatting_context.rs")
replaced = text(root / "replaced_with_children_formatting_context.rs")
inline = text(root / "inline_formatting_context.rs")
flex = text(root / "flex_formatting_context.rs")
grid = text(root / "grid_formatting_context.rs")
table = text(root / "table_formatting_context.rs")

fragments = [
    ("derive_baselines", root / "formatting_context.rs"),
    ("finalize_atomic_root_block_size", root / "formatting_context.rs"),
    ("compute_and_store_baselines in block FC", root / "block_formatting_context.rs"),
    ("derive_baselines calls", root / "block_formatting_context.rs"),
    ("box_baseline_with_content_baselines", root / "formatting_context.rs"),
    ("input_derives_from_children handling", root / "formatting_context.rs"),
    ("derive_baselines implementation", None),
]
for (name, file) in fragments:
    print(f"--- {name}: {file or 'formatting_context.rs'} ---")
    target = file.read_text() if file else ctx
    if name == "derive_baselines implementation":
        start = target.find("pub(crate) fn derive_baselines")
        end = target.find("pub(crate) struct ChildLayoutResult", start)
    else:
        start = target.find("pub(crate) fn " + name)
        if start == -1:
            start = target.find("fn " + name)
        if start == -1:
            print("not found")
            continue
        if name == "derive_baselines implementation":
            end = target.find("pub(crate) struct ChildLayoutResult", start)
        else:
            next_new = target.find("\nfn ", start + 1)
            end = target.find("\n}", target.rfind("{", start, next_new if next_new != -1 else len(target))) + 2 if next_new != -1 else len(target)
            if target.find("\n)", end) != -1:
                end = target.find("\n)", end) + 2
            end = min(end, target.find("\n}", end) + 2)
    print(target[start:end])

print("--- invariants ---")

rf = ctx.find("FormattingContextImplementation::ReplacedWithChildren => layout_replaced_with_children(run, body_input),")
final_start = ctx.find("fn finalize_block_level_root(", rf)
print(f"run_formatting_context ReplacedWithChildren branch exists: {rf != -1}")
print(f"finalize_block_level_root exists after ReplacedWithChildren case: {final_start != -1}")
print(f"finalize_block_level_root contains store_derived_baselines: {'store_derived_baselines(' in ctx[final_start:ctx.find('fn size_skipped_independent_root', final_start)]}")
print(f"finalize_block_level_root contains record_replaced_block_size: {'record_replaced_block_size(' in ctx[final_start:ctx.find('fn size_skipped_independent_root', final_start)]}")

ds_start = ctx.find("pub(crate) fn derive_baselines")
ds_end = ctx.find("pub(crate) struct ChildLayoutResult", ds_start)
ds = ctx[ds_start:ds_end]
print(f"derive_baselines handles block container children: {'child_state.content_baselines_from_cells' in ds}")
print(f"derive_baselines handles flex container children: {'fctx.derived_baselines_of_root_box' in ds}")
print(f"derive_baselines handles grid container children: {'gctx.derived_baselines_of_root_box' in ds}")
print(f"derive_baselines handles table formatting context: {'TableFormattingContext' in ds}")

stored_calls = []
for p in [root / "block_formatting_context.rs", root / "inline_formatting_context.rs", root / "flex_formatting_context.rs", root / "grid_formatting_context.rs", root / "table_formatting_context.rs"]:
    pc = p.read_text()
    if "crate::layout::store_derived_baselines(" in pc:
        for m in re.finditer(r"crate::layout::store_derived_baselines\s*\(", pc):
            line = pc[:m.start()].count("\n") + 1
            stored_calls.append((p, line, pc[pc.rfind("\n", 0, m.start()-1):pc.find("\n", m.start()) + 1].strip()))
print("store_derived_baselines call sites:")
for p,line,snippet in stored_calls:
    print(f"  {p}:{line} {snippet}")
PY

Repository: LadybirdBrowser/ladybird

Length of output: 50380

Store baselines for ReplacedWithChildren roots.

layout_replaced_with_children always returns DerivedBaselines::default(), and run_formatting_context does not call store_derived_baselines for ReplacedWithChildren roots. Derive and forward the wrapper baseline result from layout_replaced_with_children, or explicitly derive/store baselines from the wrapper child instead of relying on finalize_block_level_root, so <input> elements with block shadow-tree children do not collapse to the margin-box bottom edge.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In
`@Libraries/LibWeb/Rust/src/layout/replaced_with_children_formatting_context.rs`
around lines 69 - 73, Update layout_replaced_with_children and the
ReplacedWithChildren path in run_formatting_context to derive and store the
wrapper child’s baselines instead of returning DerivedBaselines::default().
Ensure the derived baselines are forwarded or explicitly passed to
store_derived_baselines so input elements with block shadow-tree children retain
the wrapper baseline.

}
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