From 1ad3b8730283ade32d64c43b45de5aca59930de0 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Sun, 17 Feb 2019 10:19:54 +1100
Subject: [PATCH] Collapse jumps based on current index change

The previous method, while likely more correct, could restore jump
lists containing references to already removed buffers.
---
 src/commands.cc | 13 ++++++-------
 src/context.cc  |  8 +++++++-
 src/context.hh  |  4 +++-
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/commands.cc b/src/commands.cc
index 5db90b5c..5f7e1530 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -1754,18 +1754,17 @@ void context_wrap(const ParametersParser& parser, Context& context, StringView d
     else
     {
         const bool collapse_jumps = not (c.flags() & Context::Flags::Draft) and context.has_buffer();
-        auto original_jump_list = collapse_jumps ? c.jump_list() : Optional<JumpList>{};
+        auto& jump_list = c.jump_list();
+        const size_t prev_index = jump_list.current_index();
         auto jump = collapse_jumps ? c.selections() : Optional<SelectionList>{};
 
         func(parser, c);
 
         // If the jump list got mutated, collapse all jumps into a single one from original selections
-        if (collapse_jumps and c.jump_list() != *original_jump_list)
-        {
-            original_jump_list->push(std::move(*jump));
-            if (c.jump_list() != *original_jump_list)
-                c.jump_list() = std::move(*original_jump_list);
-        }
+        if (auto index = jump_list.current_index();
+            collapse_jumps and index > prev_index and
+            contains(BufferManager::instance(), &jump->buffer()))
+            jump_list.push(std::move(*jump), prev_index);
     }
 }
 
diff --git a/src/context.cc b/src/context.cc
index b3b82938..d97073d0 100644
--- a/src/context.cc
+++ b/src/context.cc
@@ -76,8 +76,14 @@ void Context::print_status(DisplayLine status) const
         client().print_status(std::move(status));
 }
 
-void JumpList::push(SelectionList jump)
+void JumpList::push(SelectionList jump, Optional<size_t> index)
 {
+    if (index)
+    {
+        m_current = *index;
+        kak_assert(m_current <= m_jumps.size());
+    }
+
     if (m_current != m_jumps.size())
         m_jumps.erase(m_jumps.begin()+m_current+1, m_jumps.end());
     m_jumps.erase(std::remove(begin(m_jumps), end(m_jumps), jump),
diff --git a/src/context.hh b/src/context.hh
index d8830b2e..b71e6547 100644
--- a/src/context.hh
+++ b/src/context.hh
@@ -21,7 +21,7 @@ class AliasRegistry;
 
 struct JumpList
 {
-    void push(SelectionList jump);
+    void push(SelectionList jump, Optional<size_t> index = {});
     const SelectionList& forward(Context& context, int count);
     const SelectionList& backward(Context& context, int count);
     void forget_buffer(Buffer& buffer);
@@ -33,6 +33,8 @@ struct JumpList
 
     friend bool operator!=(const JumpList& lhs, const JumpList& rhs) { return not (lhs == rhs); }
 
+    size_t current_index() const { return m_current; }
+
 private:
     using Contents = Vector<SelectionList, MemoryDomain::Selections>;
     Contents m_jumps;