Revert Label text reshaping fix #71553 and subsequent regression fixes

Despite a lot of great work from Pedro to try to improve the Label text
reshaping logic and fix subsequent regressions, we found ourselves still
chasing more edge cases, such as #73736 (which got reverted already due
to it causing yet another regression).

In parallel, it seems like the crash scenario that #71553 was addressing
got solved differently in the master branch, so it appears like this
change is no longer necessary at all (at least not urgently), so we
decided to revert to the previous known "ok" state of Label.

- Revert #71553 "Prevent infinite cascade of re-layout after label text reshaping"
This reverts commit ed8c5cd52f7914daf6f1aa309581ca3b9b048a2e.

- Revert #72387 "Enhance label sizing algorithm"
This reverts commit 5131b81a4db89d2ef05f7cff7b4b5ea93b140aec.

- Revert #73234 "Fix blank non-autowrapping labels"
This reverts commit 3ccabee9ae8f261aa7b0110482fbb5d2500d2e38.

- Revert #73343 "Make label sizing algorithm more robust"
This reverts commit 4f7f1ef60bdbb0c6d6096d3d99f3e967af7d7a39.

- Revert #73426 "Fix width determination of non-trimmed, non-wrapped labels"
This reverts commit 73b6c0b972150c7cee3975080bedc510f1088adb.

2 files changed, 107 insertions, 132 deletions

diff --git a/scene/gui/label.cpp b/scene/gui/label.cpp
index b861d7af01..59f7511894 100644
--- a/scene/gui/label.cpp
+++ b/scene/gui/label.cpp
@@ -86,7 +86,7 @@ int Label::get_line_height(int p_line) const {
 	}
 }
 
-bool Label::_shape() {
+void Label::_shape() {
 	Ref<StyleBox> style = theme_cache.normal_style;
 	int width = (get_size().width - style->get_minimum_size().width);
 
@@ -101,7 +101,7 @@ bool Label::_shape() {
 		}
 		const Ref<Font> &font = (settings.is_valid() && settings->get_font().is_valid()) ? settings->get_font() : theme_cache.font;
 		int font_size = settings.is_valid() ? settings->get_font_size() : theme_cache.font_size;
-		ERR_FAIL_COND_V(font.is_null(), true);
+		ERR_FAIL_COND(font.is_null());
 		String txt = (uppercase) ? TS->string_to_upper(xl_text, language) : xl_text;
 		if (visible_chars >= 0 && visible_chars_behavior == TextServer::VC_CHARS_BEFORE_SHAPING) {
 			txt = txt.substr(0, visible_chars);
@@ -121,7 +121,6 @@ bool Label::_shape() {
 		dirty = false;
 		font_dirty = false;
 		lines_dirty = true;
-		// Note for future maintainers: forgetting stable width here (e.g., setting it to -1) may fix still undiscovered bugs.
 	}
 
 	if (lines_dirty) {
@@ -129,143 +128,126 @@ bool Label::_shape() {
 			TS->free_rid(lines_rid[i]);
 		}
 		lines_rid.clear();
-	}
-
-	Size2i prev_minsize = minsize;
-	minsize = Size2();
 
-	bool can_process_lines = false;
-	if (xl_text.length() == 0) {
-		can_process_lines = true;
-		lines_dirty = false;
-	} else {
-		// With autowrap on or off with trimming enabled, we won't compute the minimum size until width is stable
-		// (two shape requests in a row with the same width.) This avoids situations in which the initial width is
-		// very narrow and the label would break text into many very short lines, causing a very tall label that can
-		// leave a deformed container. In the remaining case (namely, autowrap off and no trimming), the label is
-		// free to dictate its own width, something that will be taken advtantage of.
-		bool can_dictate_width = autowrap_mode == TextServer::AUTOWRAP_OFF && overrun_behavior == TextServer::OVERRUN_NO_TRIMMING;
-		bool is_width_stable = get_size().width == stable_width;
-		can_process_lines = can_dictate_width || is_width_stable;
-		stable_width = get_size().width;
-
-		if (can_process_lines) {
-			if (lines_dirty) {
-				BitField<TextServer::LineBreakFlag> autowrap_flags = TextServer::BREAK_MANDATORY;
-				switch (autowrap_mode) {
-					case TextServer::AUTOWRAP_WORD_SMART:
-						autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_ADAPTIVE | TextServer::BREAK_MANDATORY;
-						break;
-					case TextServer::AUTOWRAP_WORD:
-						autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_MANDATORY;
-						break;
-					case TextServer::AUTOWRAP_ARBITRARY:
-						autowrap_flags = TextServer::BREAK_GRAPHEME_BOUND | TextServer::BREAK_MANDATORY;
-						break;
-					case TextServer::AUTOWRAP_OFF:
-						break;
-				}
-				autowrap_flags = autowrap_flags | TextServer::BREAK_TRIM_EDGE_SPACES;
+		BitField<TextServer::LineBreakFlag> autowrap_flags = TextServer::BREAK_MANDATORY;
+		switch (autowrap_mode) {
+			case TextServer::AUTOWRAP_WORD_SMART:
+				autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_ADAPTIVE | TextServer::BREAK_MANDATORY;
+				break;
+			case TextServer::AUTOWRAP_WORD:
+				autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_MANDATORY;
+				break;
+			case TextServer::AUTOWRAP_ARBITRARY:
+				autowrap_flags = TextServer::BREAK_GRAPHEME_BOUND | TextServer::BREAK_MANDATORY;
+				break;
+			case TextServer::AUTOWRAP_OFF:
+				break;
+		}
+		autowrap_flags = autowrap_flags | TextServer::BREAK_TRIM_EDGE_SPACES;
 
-				PackedInt32Array line_breaks = TS->shaped_text_get_line_breaks(text_rid, width, 0, autowrap_flags);
-				for (int i = 0; i < line_breaks.size(); i = i + 2) {
-					RID line = TS->shaped_text_substr(text_rid, line_breaks[i], line_breaks[i + 1] - line_breaks[i]);
-					lines_rid.push_back(line);
-				}
-			}
+		PackedInt32Array line_breaks = TS->shaped_text_get_line_breaks(text_rid, width, 0, autowrap_flags);
+		for (int i = 0; i < line_breaks.size(); i = i + 2) {
+			RID line = TS->shaped_text_substr(text_rid, line_breaks[i], line_breaks[i + 1] - line_breaks[i]);
+			lines_rid.push_back(line);
+		}
+	}
 
-			if (can_dictate_width) {
-				for (int i = 0; i < lines_rid.size(); i++) {
-					if (minsize.width < TS->shaped_text_get_size(lines_rid[i]).x) {
-						minsize.width = TS->shaped_text_get_size(lines_rid[i]).x;
-					}
-				}
+	if (xl_text.length() == 0) {
+		minsize = Size2(1, get_line_height());
+		return;
+	}
 
-				width = (minsize.width - style->get_minimum_size().width);
+	if (autowrap_mode == TextServer::AUTOWRAP_OFF) {
+		minsize.width = 0.0f;
+		for (int i = 0; i < lines_rid.size(); i++) {
+			if (minsize.width < TS->shaped_text_get_size(lines_rid[i]).x) {
+				minsize.width = TS->shaped_text_get_size(lines_rid[i]).x;
 			}
+		}
+	}
 
-			if (lines_dirty) {
-				BitField<TextServer::TextOverrunFlag> overrun_flags = TextServer::OVERRUN_NO_TRIM;
-				switch (overrun_behavior) {
-					case TextServer::OVERRUN_TRIM_WORD_ELLIPSIS:
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM_WORD_ONLY);
-						overrun_flags.set_flag(TextServer::OVERRUN_ADD_ELLIPSIS);
-						break;
-					case TextServer::OVERRUN_TRIM_ELLIPSIS:
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
-						overrun_flags.set_flag(TextServer::OVERRUN_ADD_ELLIPSIS);
-						break;
-					case TextServer::OVERRUN_TRIM_WORD:
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM_WORD_ONLY);
-						break;
-					case TextServer::OVERRUN_TRIM_CHAR:
-						overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
-						break;
-					case TextServer::OVERRUN_NO_TRIMMING:
-						break;
-				}
+	if (lines_dirty) {
+		BitField<TextServer::TextOverrunFlag> overrun_flags = TextServer::OVERRUN_NO_TRIM;
+		switch (overrun_behavior) {
+			case TextServer::OVERRUN_TRIM_WORD_ELLIPSIS:
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM_WORD_ONLY);
+				overrun_flags.set_flag(TextServer::OVERRUN_ADD_ELLIPSIS);
+				break;
+			case TextServer::OVERRUN_TRIM_ELLIPSIS:
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
+				overrun_flags.set_flag(TextServer::OVERRUN_ADD_ELLIPSIS);
+				break;
+			case TextServer::OVERRUN_TRIM_WORD:
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM_WORD_ONLY);
+				break;
+			case TextServer::OVERRUN_TRIM_CHAR:
+				overrun_flags.set_flag(TextServer::OVERRUN_TRIM);
+				break;
+			case TextServer::OVERRUN_NO_TRIMMING:
+				break;
+		}
 
-				// Fill after min_size calculation.
+		// Fill after min_size calculation.
 
-				int visible_lines = lines_rid.size();
-				if (max_lines_visible >= 0 && visible_lines > max_lines_visible) {
-					visible_lines = max_lines_visible;
-				}
-				if (autowrap_mode != TextServer::AUTOWRAP_OFF) {
-					bool lines_hidden = visible_lines > 0 && visible_lines < lines_rid.size();
-					if (lines_hidden) {
-						overrun_flags.set_flag(TextServer::OVERRUN_ENFORCE_ELLIPSIS);
-					}
-					if (horizontal_alignment == HORIZONTAL_ALIGNMENT_FILL) {
-						for (int i = 0; i < lines_rid.size(); i++) {
-							if (i < visible_lines - 1 || lines_rid.size() == 1) {
-								TS->shaped_text_fit_to_width(lines_rid[i], width);
-							} else if (i == (visible_lines - 1)) {
-								TS->shaped_text_overrun_trim_to_width(lines_rid[visible_lines - 1], width, overrun_flags);
-							}
-						}
-					} else if (lines_hidden) {
+		if (autowrap_mode != TextServer::AUTOWRAP_OFF) {
+			int visible_lines = get_visible_line_count();
+			bool lines_hidden = visible_lines > 0 && visible_lines < lines_rid.size();
+			if (lines_hidden) {
+				overrun_flags.set_flag(TextServer::OVERRUN_ENFORCE_ELLIPSIS);
+			}
+			if (horizontal_alignment == HORIZONTAL_ALIGNMENT_FILL) {
+				for (int i = 0; i < lines_rid.size(); i++) {
+					if (i < visible_lines - 1 || lines_rid.size() == 1) {
+						TS->shaped_text_fit_to_width(lines_rid[i], width);
+					} else if (i == (visible_lines - 1)) {
 						TS->shaped_text_overrun_trim_to_width(lines_rid[visible_lines - 1], width, overrun_flags);
 					}
-				} else {
-					// Autowrap disabled.
-					for (int i = 0; i < lines_rid.size(); i++) {
-						if (horizontal_alignment == HORIZONTAL_ALIGNMENT_FILL) {
-							TS->shaped_text_fit_to_width(lines_rid[i], width);
-							overrun_flags.set_flag(TextServer::OVERRUN_JUSTIFICATION_AWARE);
-							TS->shaped_text_overrun_trim_to_width(lines_rid[i], width, overrun_flags);
-							TS->shaped_text_fit_to_width(lines_rid[i], width, TextServer::JUSTIFICATION_WORD_BOUND | TextServer::JUSTIFICATION_KASHIDA | TextServer::JUSTIFICATION_CONSTRAIN_ELLIPSIS);
-						} else {
-							TS->shaped_text_overrun_trim_to_width(lines_rid[i], width, overrun_flags);
-						}
-					}
-				}
-
-				int last_line = MIN(lines_rid.size(), visible_lines + lines_skipped);
-				int line_spacing = settings.is_valid() ? settings->get_line_spacing() : theme_cache.line_spacing;
-				for (int64_t i = lines_skipped; i < last_line; i++) {
-					minsize.height += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
 				}
-
-				lines_dirty = false;
+			} else if (lines_hidden) {
+				TS->shaped_text_overrun_trim_to_width(lines_rid[visible_lines - 1], width, overrun_flags);
 			}
 		} else {
-			callable_mp(this, &Label::_shape).call_deferred();
+			// Autowrap disabled.
+			for (int i = 0; i < lines_rid.size(); i++) {
+				if (horizontal_alignment == HORIZONTAL_ALIGNMENT_FILL) {
+					TS->shaped_text_fit_to_width(lines_rid[i], width);
+					overrun_flags.set_flag(TextServer::OVERRUN_JUSTIFICATION_AWARE);
+					TS->shaped_text_overrun_trim_to_width(lines_rid[i], width, overrun_flags);
+					TS->shaped_text_fit_to_width(lines_rid[i], width, TextServer::JUSTIFICATION_WORD_BOUND | TextServer::JUSTIFICATION_KASHIDA | TextServer::JUSTIFICATION_CONSTRAIN_ELLIPSIS);
+				} else {
+					TS->shaped_text_overrun_trim_to_width(lines_rid[i], width, overrun_flags);
+				}
+			}
 		}
+		lines_dirty = false;
 	}
 
-	if (draw_pending) {
-		queue_redraw();
-		draw_pending = false;
-	}
+	_update_visible();
 
-	if (minsize != prev_minsize) {
+	if (autowrap_mode == TextServer::AUTOWRAP_OFF || !clip || overrun_behavior == TextServer::OVERRUN_NO_TRIMMING) {
 		update_minimum_size();
 	}
+}
+
+void Label::_update_visible() {
+	int line_spacing = settings.is_valid() ? settings->get_line_spacing() : theme_cache.line_spacing;
+	Ref<StyleBox> style = theme_cache.normal_style;
+	int lines_visible = lines_rid.size();
 
-	return can_process_lines;
+	if (max_lines_visible >= 0 && lines_visible > max_lines_visible) {
+		lines_visible = max_lines_visible;
+	}
+
+	minsize.height = 0;
+	int last_line = MIN(lines_rid.size(), lines_visible + lines_skipped);
+	for (int64_t i = lines_skipped; i < last_line; i++) {
+		minsize.height += TS->shaped_text_get_size(lines_rid[i]).y + line_spacing;
+		if (minsize.height > (get_size().height - style->get_minimum_size().height + line_spacing)) {
+			break;
+		}
+	}
 }
 
 inline void draw_glyph(const Glyph &p_gl, const RID &p_canvas, const Color &p_font_color, const Vector2 &p_ofs) {
@@ -375,11 +357,7 @@ void Label::_notification(int p_what) {
 			}
 
 			if (dirty || font_dirty || lines_dirty) {
-				if (!_shape()) {
-					// There will be another pass.
-					draw_pending = true;
-					break;
-				}
+				_shape();
 			}
 
 			RID ci = get_canvas_item();
@@ -622,8 +600,6 @@ void Label::_notification(int p_what) {
 				}
 				ofs.y += TS->shaped_text_get_descent(lines_rid[i]) + vsep + line_spacing;
 			}
-
-			draw_pending = false;
 		} break;
 
 		case NOTIFICATION_THEME_CHANGED: {
@@ -915,7 +891,7 @@ void Label::set_lines_skipped(int p_lines) {
 	}
 
 	lines_skipped = p_lines;
-	lines_dirty = true;
+	_update_visible();
 	queue_redraw();
 }
 
@@ -929,7 +905,7 @@ void Label::set_max_lines_visible(int p_lines) {
 	}
 
 	max_lines_visible = p_lines;
-	lines_dirty = true;
+	_update_visible();
 	queue_redraw();
 }
 
diff --git a/scene/gui/label.h b/scene/gui/label.h
index 36b85f7af8..2350525236 100644
--- a/scene/gui/label.h
+++ b/scene/gui/label.h
@@ -46,7 +46,6 @@ private:
 	bool clip = false;
 	TextServer::OverrunBehavior overrun_behavior = TextServer::OVERRUN_NO_TRIMMING;
 	Size2 minsize;
-	real_t stable_width = -1;
 	bool uppercase = false;
 
 	bool lines_dirty = true;
@@ -65,7 +64,6 @@ private:
 	float visible_ratio = 1.0;
 	int lines_skipped = 0;
 	int max_lines_visible = -1;
-	bool draw_pending = false;
 
 	Ref<LabelSettings> settings;
 
@@ -83,7 +81,8 @@ private:
 		int font_shadow_outline_size;
 	} theme_cache;
 
-	bool _shape();
+	void _update_visible();
+	void _shape();
 	void _invalidate();
 
 protected: