From 7c1aeb387afa9a1b7d01ee9ea3a2950a3cc5ac8b Mon Sep 17 00:00:00 2001
From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Thu, 23 May 2019 10:26:08 +0200
Subject: [PATCH] Fixup da2696cc: do not clear useful information from row

Ensure before calling breakRow that the row is empty.

Remove Row::clear(), which has unnatural semantics.

Fixes bug #11396.
---
 src/Row.h           | 2 --
 src/TextMetrics.cpp | 5 +++--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/Row.h b/src/Row.h
index e4a8e689b6..d210174ef9 100644
--- a/src/Row.h
+++ b/src/Row.h
@@ -261,8 +261,6 @@ public:
 	Element const & back() const { return elements_.back(); }
 	/// remove last element
 	void pop_back();
-	/// remove all row elements
-	void clear() { *this = Row(); }
 	/**
 	 * if row width is too large, remove all elements after last
 	 * separator and update endpos if necessary. If all that
diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 6f195a6022..fc610ad854 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -524,10 +524,11 @@ bool TextMetrics::redoParagraph(pit_type const pit, bool const align_rows)
 	do {
 		if (row_index == pm.rows().size())
 			pm.rows().push_back(Row());
+		else
+			pm.rows()[row_index] = Row();
 		Row & row = pm.rows()[row_index];
 		row.pit(pit);
 		row.pos(first);
-		row.pit(pit);
 		need_new_row = breakRow(row, right_margin);
 		setRowHeight(row);
 		row.changed(true);
@@ -881,6 +882,7 @@ private:
  */
 bool TextMetrics::breakRow(Row & row, int const right_margin) const
 {
+	LATTEST(row.empty());
 	Paragraph const & par = text_->getPar(row.pit());
 	pos_type const end = par.size();
 	pos_type const pos = row.pos();
@@ -888,7 +890,6 @@ bool TextMetrics::breakRow(Row & row, int const right_margin) const
 	bool const is_rtl = text_->isRTL(row.pit());
 	bool need_new_row = false;
 
-	row.clear();
 	row.left_margin = leftMargin(row.pit(), pos);
 	row.right_margin = right_margin;
 	if (is_rtl)
-- 
2.39.5