(REGRESSION: 267587@main) Text indent is incorrect when paragraph is …

…affected by a floating element

https://bugs.webkit.org/show_bug.cgi?id=265216
<rdar://problem/118701491>

Reviewed by Antti Koivisto.

Before 267587@main (which merged all the float constraints codepaths), we ignored the text-indent during the _initial_ constraint computation
and adjusted the line rect later.
At 267587@main, we started adding the text-indent value twice to the line rect; first while computing the initial constraint and
the second time when we would normally add it.

* LayoutTests/fast/text/text-indent-with-intrusive-float-expected.html: Added.
* LayoutTests/fast/text/text-indent-with-intrusive-float.html: Added.
* Source/WebCore/layout/formattingContexts/inline/InlineLineBuilder.cpp:
(WebCore::Layout::LineBuilder::initialConstraintsForLine const): Let's go back to "before 267587@main" state.
(WebCore::Layout::LineBuilder::floatConstrainedRect const): Add some comment and change variable names to reflect what they mean.

Canonical link: https://commits.webkit.org/271080@main

LayoutTests/fast/text/text-indent-with-intrusive-float-expected.html

@@ -0,0 +1,14 @@
+<style>
+.inline-block {
+  display: inline-block;
+  margin-right: 100px;
+}
+
+div {
+  width: 100px;
+  height: 100px;
+  background-color: green;
+}
+</style>
+<div class=inline-block></div><div class=inline-block></div>
+<div></div>

LayoutTests/fast/text/text-indent-with-intrusive-float.html

@@ -0,0 +1,18 @@
+<style>
+.inline-block {
+  display: inline-block;
+  width: 100px;
+  height: 100px;
+  background-color: green;
+}
+
+.float-box {
+  width: 100px;
+  height: 100px;
+  float: left;
+  background-color: green;
+}
+</style>
+<!-- PASS if text-indent puts a 100px gap between the float and the inline content -->
+<div><div class="float-box"></div><div style="text-indent: 100px"><div class=inline-block></div></div></div>
+<div><div class="float-box"></div><div style="text-indent: -100px"><div class=inline-block></div></div></div>

Source/WebCore/layout/formattingContexts/inline/InlineLineBuilder.cpp

@@ -529,9 +529,9 @@ LineContent LineBuilder::placeInlineAndFloatContent(const InlineItemRange& needs
 LineBuilder::UsedConstraints LineBuilder::initialConstraintsForLine(const InlineRect& initialLineLogicalRect, std::optional<bool> previousLineEndsWithLineBreak) const
 {
     auto isIntrinsicWidthMode = isInIntrinsicWidthMode() ? InlineFormattingUtils::IsIntrinsicWidthMode::Yes : InlineFormattingUtils::IsIntrinsicWidthMode::No;
-    auto textIndent = formattingContext().formattingUtils().computedTextIndent(isIntrinsicWidthMode, previousLineEndsWithLineBreak, initialLineLogicalRect.width());
-
-    return floatConstrainedRect(initialLineLogicalRect, textIndent);
+    auto constraints = floatConstrainedRect(initialLineLogicalRect, { });
+    constraints.marginStart = formattingContext().formattingUtils().computedTextIndent(isIntrinsicWidthMode, previousLineEndsWithLineBreak, initialLineLogicalRect.width());
+    return constraints;
 }
 
 InlineLayoutUnit LineBuilder::leadingPunctuationWidthForLineCandiate(size_t firstInlineTextItemIndex, size_t candidateContentStartIndex) const
@@ -756,20 +756,20 @@ LineBuilder::UsedConstraints LineBuilder::floatConstrainedRect(const InlineRect&
             return { logicalRect, marginStart, { } };
 
         auto isConstrainedByFloat = OptionSet<UsedFloat> { };
-        auto adjustedLogicalRect = logicalRect;
-        adjustedLogicalRect.shiftLeftBy(-marginStart);
+        // text-indent acts as (start)margin on the line. When looking for intrusive floats we need to check against the line's _margin_ box.
+        auto marginBoxRect = InlineRect { logicalRect.top(), logicalRect.left() - marginStart, logicalRect.width() + marginStart, logicalRect.height() };
 
-        if (constraints.left && constraints.left->x > adjustedLogicalRect.left()) {
-            adjustedLogicalRect.shiftLeftTo(constraints.left->x);
+        if (constraints.left && constraints.left->x > marginBoxRect.left()) {
+            marginBoxRect.shiftLeftTo(constraints.left->x);
             isConstrainedByFloat.add(UsedFloat::Left);
         }
-        if (constraints.right && constraints.right->x < adjustedLogicalRect.right()) {
-            adjustedLogicalRect.setRight(std::max<InlineLayoutUnit>(adjustedLogicalRect.left(), constraints.right->x));
+        if (constraints.right && constraints.right->x < marginBoxRect.right()) {
+            marginBoxRect.setRight(std::max<InlineLayoutUnit>(marginBoxRect.left(), constraints.right->x));
             isConstrainedByFloat.add(UsedFloat::Right);
         }
 
-        adjustedLogicalRect.shiftLeftBy(marginStart);
-        return { adjustedLogicalRect, marginStart, isConstrainedByFloat };
+        auto lineLogicalRect = InlineRect { marginBoxRect.top(), marginBoxRect.left() + marginStart, marginBoxRect.width() - marginStart, marginBoxRect.height() };
+        return { lineLogicalRect, marginStart, isConstrainedByFloat };
     }();
 
     if (auto adjustedRect = formattingContext().quirks().adjustedRectForLineGridLineAlign(constraints.logicalRect))