[LyX/master] Fix crash when copying multiple cells in table

[Juergen Spitzmueller]

commit 6ec6db8cd9073bcb856e6a055d12ff95802e22be
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Sat Apr 8 16:55:41 2023 +0200

    Fix crash when copying multiple cells in table
    
    while having done "backwards" selection (selBegin() in a later
    column/row than selEnd())
---
 src/insets/InsetTabular.cpp |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/insets/InsetTabular.cpp b/src/insets/InsetTabular.cpp
index 163f162..69f9e73 100644
--- a/src/insets/InsetTabular.cpp
+++ b/src/insets/InsetTabular.cpp
@@ -7516,10 +7516,15 @@ docstring InsetTabular::asString(idx_type stidx, idx_type enidx,
 {
 	LASSERT(stidx <= enidx, return docstring());
 	docstring retval;
-	col_type const col1 = tabular.cellColumn(stidx);
-	col_type const col2 = tabular.cellColumn(enidx);
-	row_type const row1 = tabular.cellRow(stidx);
-	row_type const row2 = tabular.cellRow(enidx);
+	col_type col1 = tabular.cellColumn(stidx);
+	col_type col2 = tabular.cellColumn(enidx);
+	row_type row1 = tabular.cellRow(stidx);
+	row_type row2 = tabular.cellRow(enidx);
+	// stidx might be in a later column or row than enidx
+	if (col1 > col2)
+		swap(col1, col2);
+	if (row1 > row2)
+		swap(row1, row2);
 	bool first = true;
 	for (col_type col = col1; col <= col2; col++)
 		for (row_type row = row1; row <= row2; row++) {
@@ -7537,10 +7542,15 @@ ParagraphList InsetTabular::asParList(idx_type stidx, idx_type enidx)
 {
 	LASSERT(stidx <= enidx, return ParagraphList());
 	ParagraphList retval;
-	col_type const col1 = tabular.cellColumn(stidx);
-	col_type const col2 = tabular.cellColumn(enidx);
-	row_type const row1 = tabular.cellRow(stidx);
-	row_type const row2 = tabular.cellRow(enidx);
+	col_type col1 = tabular.cellColumn(stidx);
+	col_type col2 = tabular.cellColumn(enidx);
+	row_type row1 = tabular.cellRow(stidx);
+	row_type row2 = tabular.cellRow(enidx);
+	// stidx might be in a later column or row than enidx
+	if (col1 > col2)
+		swap(col1, col2);
+	if (row1 > row2)
+		swap(row1, row2);
 	for (col_type col = col1; col <= col2; col++)
 		for (row_type row = row1; row <= row2; row++)
 			for (auto const & par : tabular.cellInset(row, col)->paragraphs())