From b6c639c48732a8823303f730f7a271f487217329 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 11 Dec 2016 14:48:00 +0530
Subject: [PATCH] Fix incorrect handling of trailing whitespace for lines in
 the history buffer when resizing

---
 kitty/history.c          | 18 +++++++++++-------
 kitty_tests/datatypes.py |  7 +++++++
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/kitty/history.c b/kitty/history.c
index 3af7f66de..41efd7d45 100644
--- a/kitty/history.c
+++ b/kitty/history.c
@@ -10,6 +10,12 @@
 
 #define CELL_SIZE_H (CELL_SIZE + 1)
 
+static inline uint8_t* 
+start_of(HistoryBuf *self, index_type num) {
+    // Pointer to the start of the line with index (buffer position) num
+    return self->buf + CELL_SIZE_H * num * self->xnum;
+}
+
 static PyObject *
 new(PyTypeObject *type, PyObject *args, PyObject UNUSED *kwds) {
     HistoryBuf *self;
@@ -34,6 +40,10 @@ new(PyTypeObject *type, PyObject *args, PyObject UNUSED *kwds) {
             Py_CLEAR(self);
         } else {
             self->line->xnum = xnum;
+            for(index_type y = 0; y < self->ynum; y++) {
+                self->line->chars = (char_type*)(start_of(self, y) + 1);
+                for (index_type i = 0; i < self->xnum; i++) self->line->chars[i] = (1 << ATTRS_SHIFT) | 32;
+            }
         }
     }
 
@@ -56,12 +66,6 @@ index_of(HistoryBuf *self, index_type lnum) {
     return (self->start_of_data + idx) % self->ynum;
 }
 
-static inline uint8_t* 
-start_of(HistoryBuf *self, index_type num) {
-    // Pointer to the start of the line with index (buffer position) num
-    return self->buf + CELL_SIZE_H * num * self->xnum;
-}
-
 static inline void 
 init_line(HistoryBuf *self, index_type num, Line *l) {
     // Initialize the line l, setting its pointer to the offsets for the line at index (buffer position) num
@@ -214,7 +218,7 @@ HistoryBuf *alloc_historybuf(unsigned int lines, unsigned int columns) {
 
 #define is_src_line_continued(src_y) (map_src_index(src_y) < src->ynum - 1 ? *(start_of(src, map_src_index(src_y + 1))) : false)
 
-#define next_dest_line(cont) historybuf_push(dest); dest->line->continued = cont;
+#define next_dest_line(cont) *start_of(dest, historybuf_push(dest)) = cont; dest->line->continued = cont; 
 
 #define first_dest_line next_dest_line(false); 
 
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index 0730c2556..8e2c40101 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -321,6 +321,13 @@ class TestDataTypes(BaseTest):
         hb.rewrap(hb2)
         for i in range(hb2.ynum):
             self.ae(hb2.line(i), hb.line(i))
+        hb = filled_history_buf(5, 5)
+        hb2 = HistoryBuf(hb.ynum, hb.xnum * 2)
+        hb.rewrap(hb2)
+        hb3 = HistoryBuf(hb.ynum, hb.xnum)
+        hb2.rewrap(hb3)
+        for i in range(hb.ynum):
+            self.ae(hb.line(i), hb3.line(i))
 
     def test_ansi_repr(self):
         lb = filled_line_buf()