From cf2fffaf95f4dcf8ff9b21872de41c115054155c Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 28 Dec 2024 10:48:21 +0530
Subject: [PATCH] Fix continuation char marking when rewrapping historybuf

---
 kitty/history.c          | 16 ++++++++--------
 kitty/line.c             |  7 +++++++
 kitty_tests/datatypes.py | 12 ++++++++++++
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/kitty/history.c b/kitty/history.c
index dbbcbea5f..e98df12b1 100644
--- a/kitty/history.c
+++ b/kitty/history.c
@@ -305,13 +305,6 @@ historybuf_pop_line(HistoryBuf *self, Line *line) {
     return true;
 }
 
-static void
-history_buf_set_last_char_as_continuation(HistoryBuf *self, index_type y, bool wrapped) {
-    if (self->count > 0) {
-        cpu_lineptr(self, index_of(self, y))[self->xnum-1].next_char_was_wrapped = wrapped;
-    }
-}
-
 static PyObject*
 line(HistoryBuf *self, PyObject *val) {
 #define line_doc "Return the line with line number val. This buffer grows upwards, i.e. 0 is the most recently added line"
@@ -608,9 +601,16 @@ HistoryBuf *alloc_historybuf(unsigned int lines, unsigned int columns, unsigned
 }
 // }}}
 
+static void
+history_buf_set_last_char_as_continuation(HistoryBuf *self, index_type y, bool wrapped) {
+    if (self->count > 0) {
+        cpu_lineptr(self, index_of(self, y))[self->xnum-1].next_char_was_wrapped = wrapped;
+    }
+}
+
 index_type
 historybuf_next_dest_line(HistoryBuf *self, ANSIBuf *as_ansi_buf, Line *src_line, index_type dest_y, Line *dest_line, bool continued) {
-    history_buf_set_last_char_as_continuation(self, dest_y, continued);
+    history_buf_set_last_char_as_continuation(self, 0, continued);
     index_type idx = historybuf_push(self, as_ansi_buf);
     *attrptr(self, idx) = src_line->attrs;
     init_line(self, idx, dest_line);
diff --git a/kitty/line.c b/kitty/line.c
index a6916b5a6..e380fc49e 100644
--- a/kitty/line.c
+++ b/kitty/line.c
@@ -546,6 +546,12 @@ last_char_has_wrapped_flag(Line* self, PyObject *a UNUSED) {
     Py_RETURN_FALSE;
 }
 
+static PyObject*
+set_wrapped_flag(Line* self, PyObject *is_wrapped) {
+    self->cpu_cells[self->xnum-1].next_char_was_wrapped = PyObject_IsTrue(is_wrapped);
+    Py_RETURN_NONE;
+}
+
 static PyObject*
 __repr__(Line* self) {
     PyObject *s = line_as_unicode(self, false);
@@ -1028,6 +1034,7 @@ static PyMethodDef methods[] = {
     METHOD(set_attribute, METH_VARARGS)
     METHOD(as_ansi, METH_NOARGS)
     METHOD(last_char_has_wrapped_flag, METH_NOARGS)
+    METHODB(set_wrapped_flag, METH_O),
     METHOD(hyperlink_ids, METH_NOARGS)
     METHOD(width, METH_O)
     METHOD(url_start_at, METH_O)
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index df4ad22e7..1ff997a0d 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -486,6 +486,18 @@ class TestDataTypes(BaseTest):
             self.ae(str(hb.line(i)).rstrip(), str(3000 - 1 - i))
 
         # rewrap
+        def as_ansi(hb):
+            lines = []
+            hb.as_ansi(lines.append)
+            return ''.join(lines)
+        hb = filled_history_buf(5, 5)
+        for i in range(hb.ynum):
+            hb.line(i).set_wrapped_flag(True)
+        hb2 = HistoryBuf(3, 10)
+        before = as_ansi(hb)
+        hb.rewrap(hb2)
+        self.ae(before, as_ansi(hb2).rstrip())
+
         hb = filled_history_buf(5, 5)
         hb2 = HistoryBuf(hb.ynum, hb.xnum)
         hb.rewrap(hb2)