Tolerate restoring invalid coordinates from register

Clamp those selection after updating them to the current timestamp

Fixes #2078

3 files changed, 50 insertions, 20 deletions

diff --git a/src/normal.cc b/src/normal.cc
index e66045a3..fb295f4d 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -1734,11 +1734,22 @@ SelectionList read_selections_from_register(char reg, Context& context)
     const auto desc = content[0] | split<StringView>('@') | static_gather<error, 3>();
     Buffer& buffer = BufferManager::instance().get_buffer(desc[0]);
     const size_t timestamp = str_to_int(desc[1]);
-    const size_t main = str_to_int(desc[2]);
+    size_t main = str_to_int(desc[2]);
+
+    if (timestamp > buffer.timestamp())
+        throw runtime_error{"register '{}' refers to an invalid timestamp"};
 
     auto sels = content | skip(1) | transform(selection_from_string) | gather<Vector<Selection>>();
+    sort_selections(sels, main);
+    merge_overlapping_selections(sels, main);
+    if (timestamp < buffer.timestamp())
+        update_selections(sels, main, buffer, timestamp);
+    else
+        clamp_selections(sels, buffer);
 
-    return {SelectionList::UnsortedTag{}, buffer, std::move(sels), timestamp, main};
+    SelectionList res{buffer, std::move(sels)};
+    res.set_main_index(main);
+    return res;
 }
 
 enum class CombineOp
@@ -2012,9 +2023,7 @@ void move_cursor(Context& context, NormalParams params)
         sel.anchor() = mode == SelectMode::Extend ? sel.anchor() : cursor;
         sel.cursor() = cursor;
     }
-    selections.sort();
-
-    selections.merge_overlapping();
+    selections.sort_and_merge_overlapping();
 }
 
 void select_whole_buffer(Context& context, NormalParams)
diff --git a/src/selection.cc b/src/selection.cc
index 02358fea..c8ab543b 100644
--- a/src/selection.cc
+++ b/src/selection.cc
@@ -212,6 +212,12 @@ static void clamp(Selection& sel, const Buffer& buffer)
     sel.cursor() = buffer.clamp(sel.cursor());
 }
 
+void clamp_selections(Vector<Selection>& selections, const Buffer& buffer)
+{
+    for (auto& sel : selections)
+        clamp(sel, buffer);
+}
+
 void update_selections(Vector<Selection>& selections, size_t& main, Buffer& buffer, size_t timestamp)
 {
     if (timestamp == buffer.timestamp())
@@ -286,30 +292,41 @@ void SelectionList::check_invariant() const
 #endif
 }
 
-void SelectionList::sort()
+void sort_selections(Vector<Selection>& selections, size_t& main_index)
 {
-    if (size() == 1)
+    if (selections.size() == 1)
         return;
 
-    const auto& main = this->main();
+    const auto& main = selections[main_index];
     const auto main_begin = main.min();
-    m_main = std::count_if(begin(), end(), [&](const Selection& sel) {
-                               auto begin = sel.min();
-                               if (begin == main_begin)
-                                   return &sel < &main;
-                               else
-                                   return begin < main_begin;
-                           });
-    std::stable_sort(begin(), end(), compare_selections);
+    main_index = std::count_if(selections.begin(), selections.end(),
+                               [&](const Selection& sel) {
+        auto begin = sel.min();
+        if (begin == main_begin)
+            return &sel < &main;
+        else
+            return begin < main_begin;
+    });
+    std::stable_sort(selections.begin(), selections.end(), compare_selections);
 }
 
-void SelectionList::merge_overlapping()
+void merge_overlapping_selections(Vector<Selection>& selections, size_t& main_index)
 {
-    if (size() == 1)
+    if (selections.size() == 1)
         return;
 
-    m_selections.erase(Kakoune::merge_overlapping(begin(), end(),
-                                                  m_main, overlaps), end());
+    selections.erase(Kakoune::merge_overlapping(selections.begin(), selections.end(),
+                                                main_index, overlaps), selections.end());
+}
+
+void SelectionList::sort()
+{
+    sort_selections(m_selections, m_main);
+}
+
+void SelectionList::merge_overlapping()
+{
+    merge_overlapping_selections(m_selections, m_main);
 }
 
 void SelectionList::merge_consecutive()
diff --git a/src/selection.hh b/src/selection.hh
index 1ab93aa5..510f999b 100644
--- a/src/selection.hh
+++ b/src/selection.hh
@@ -65,6 +65,10 @@ inline bool overlaps(const Selection& lhs, const Selection& rhs)
 void update_selections(Vector<Selection>& selections, size_t& main,
                        Buffer& buffer, size_t timestamp);
 
+void sort_selections(Vector<Selection>& selections, size_t& main);
+void merge_overlapping_selections(Vector<Selection>& selections, size_t& main);
+void clamp_selections(Vector<Selection>& sel, const Buffer& buffer);
+
 enum class InsertMode : unsigned
 {
     Insert,