Refuse modification of ReadOnly buffers and make Debug buffer readonly

The debug buffer is a bit special as lots of events might mutate it,
permitting it to be modified leads to some buggy behaviour:

For example, `pipe` uses a ForwardChangeTracker to track buffer
changes, but when applied on a debug buffer with the profile flag
on, each shell execution will trigger an additional modification
of the buffer while applying the changes, leading to an assertion
failing as changes might not be happening in a forward way anymore.

Trying to modify a debug buffer will now raise an error immediatly.

1 files changed, 5 insertions, 4 deletions

diff --git a/src/buffer.hh b/src/buffer.hh
index 0eb6a4f4..d8f18015 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -139,9 +139,9 @@ public:
     void           set_fs_timestamp(timespec ts);
 
     void           commit_undo_group();
-    bool           undo(size_t count = 1) noexcept;
-    bool           redo(size_t count = 1) noexcept;
-    bool           move_to(size_t history_id) noexcept;
+    bool           undo(size_t count = 1);
+    bool           redo(size_t count = 1);
+    bool           move_to(size_t history_id);
     size_t         current_history_id() const noexcept;
     size_t         next_history_id() const noexcept { return m_next_history_id; }
 
@@ -218,6 +218,7 @@ public:
     void on_registered();
     void on_unregistered();
 
+    void throw_if_read_only() const;
 private:
     void on_option_changed(const Option& option) override;
 
@@ -272,7 +273,7 @@ private:
     SafePtr<HistoryNode>  m_last_save_history_cursor;
     UndoGroup             m_current_undo_group;
 
-    void move_to(HistoryNode* history_node) noexcept;
+    void move_to(HistoryNode* history_node);
 
     template<typename Func> HistoryNode* find_history_node(HistoryNode* node, const Func& func);