commit 16da47f4749b49660d85b3d00aaa00d66098027f
parent ec365a10924bc289fe30e1baf1f5511d207f6704
Author: zeertzjq <zeertzjq@outlook.com>
Date: Thu, 12 Feb 2026 20:10:02 +0800
fix(terminal): changing height may lead to wrong scrollback (#37824)
Problem: Changing terminal height immediately after outputting lines
may lead to wrong scrollback.
Solution: Insert pending scrollback lines before the old window height.
Diffstat:
3 files changed, 186 insertions(+), 25 deletions(-)
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
@@ -151,14 +151,16 @@ struct terminal {
// - receive data from libvterm as a result of key presses.
char textbuf[TEXTBUF_SIZE];
- ScrollbackLine **sb_buffer; // Scrollback storage.
- size_t sb_current; // Lines stored in sb_buffer.
- size_t sb_size; // Capacity of sb_buffer.
- // "virtual index" that points to the first sb_buffer row that we need to
- // push to the terminal buffer when refreshing the scrollback.
+ ScrollbackLine **sb_buffer; ///< Scrollback storage.
+ size_t sb_current; ///< Lines stored in sb_buffer.
+ size_t sb_size; ///< Capacity of sb_buffer.
+ /// "virtual index" that points to the first sb_buffer row that we need to
+ /// push to the terminal buffer when refreshing the scrollback.
int sb_pending;
- size_t sb_deleted; // Lines deleted from sb_buffer.
- size_t sb_deleted_last; // Value of sb_deleted on last refresh_scrollback()
+ size_t sb_deleted; ///< Lines deleted from sb_buffer.
+ size_t old_sb_deleted; ///< Value of sb_deleted on last refresh_scrollback().
+ /// Lines in the terminal buffer belonging to the screen instead of the scrollback.
+ int old_height;
char *title; // VTermStringFragment buffer
size_t title_len;
@@ -561,6 +563,7 @@ Terminal *terminal_alloc(buf_T *buf, TerminalOptions opts)
ml_delete_buf(buf, 1, false);
}
deleted_lines_buf(buf, 1, line_count);
+ term->old_height = 1;
return term;
}
@@ -1624,6 +1627,8 @@ static int term_sb_pop(int cols, VTermScreenCell *cells, void *data)
if (term->sb_pending > 0) {
term->sb_pending--;
+ } else {
+ term->old_height++;
}
ScrollbackLine *sbrow = term->sb_buffer[0];
@@ -2387,10 +2392,10 @@ static void adjust_scrollback(Terminal *term, buf_T *buf)
// Refresh the scrollback of an invalidated terminal.
static void refresh_scrollback(Terminal *term, buf_T *buf)
{
- linenr_T deleted = (linenr_T)(term->sb_deleted - term->sb_deleted_last);
+ linenr_T deleted = (linenr_T)(term->sb_deleted - term->old_sb_deleted);
deleted = MIN(deleted, buf->b_ml.ml_line_count);
mark_adjust_buf(buf, 1, deleted, MAXLNUM, -deleted, true, kMarkAdjustTerm, kExtmarkUndo);
- term->sb_deleted_last = term->sb_deleted;
+ term->old_sb_deleted = term->sb_deleted;
int width, height;
vterm_get_size(term->vt, &height, &width);
@@ -2404,24 +2409,14 @@ static void refresh_scrollback(Terminal *term, buf_T *buf)
}
max_line_count += term->sb_pending;
- // May still have pending scrollback after increase in terminal height if the
- // scrollback wasn't refreshed in time; append these to the top of the buffer.
- int row_offset = term->sb_pending;
- while (term->sb_pending > 0 && buf->b_ml.ml_line_count < height) {
- fetch_row(term, term->sb_pending - row_offset - 1, width);
- ml_append_buf(buf, 0, term->textbuf, 0, false);
- appended_lines_buf(buf, 0, 1);
- term->sb_pending--;
- }
-
- row_offset -= term->sb_pending;
+ int old_height = MIN(term->old_height, buf->b_ml.ml_line_count);
while (term->sb_pending > 0) {
// This means that either the window height has decreased or the screen
// became full and libvterm had to push all rows up. Convert the first
// pending scrollback row into a string and append it just above the visible
// section of the buffer.
- fetch_row(term, -term->sb_pending - row_offset, width);
- int buf_index = buf->b_ml.ml_line_count - height;
+ fetch_row(term, -term->sb_pending, width);
+ int buf_index = buf->b_ml.ml_line_count - old_height;
ml_append_buf(buf, buf_index, term->textbuf, 0, false);
appended_lines_buf(buf, buf_index, 1);
term->sb_pending--;
@@ -2467,6 +2462,7 @@ static void refresh_screen(Terminal *term, buf_T *buf)
added++;
}
}
+ term->old_height = height;
int change_start = row_to_linenr(term, term->invalid_start);
int change_end = change_start + changed;
diff --git a/test/functional/terminal/scrollback_spec.lua b/test/functional/terminal/scrollback_spec.lua
@@ -1103,7 +1103,7 @@ describe('pending scrollback line handling', function()
end)
end)
-describe('nvim_open_term()', function()
+describe('scrollback is correct', function()
local screen --- @type test.functional.ui.screen
local buf --- @type integer
local win --- @type integer
@@ -1141,6 +1141,8 @@ describe('nvim_open_term()', function()
for i = start, stop do
eq(('TEST %d'):format(i), lines[i - start + 1])
end
+ eq('', lines[#lines])
+ eq(stop - start + 2, #lines)
end
local function check_common()
@@ -1156,7 +1158,7 @@ describe('nvim_open_term()', function()
]])
end
- it('on buffer with fewer lines than scrollback', function()
+ it('with nvim_open_term() on buffer with fewer lines than scrollback', function()
exec_lua(function()
vim.api.nvim_open_term(buf, {})
vim.api.nvim_win_set_cursor(win, { 3, 0 })
@@ -1175,7 +1177,7 @@ describe('nvim_open_term()', function()
check_common()
end)
- it('on buffer with more lines than scrollback', function()
+ it('with nvim_open_term() on buffer with more lines than scrollback', function()
api.nvim_set_option_value('scrollback', 10, { buf = buf })
exec_lua(function()
vim.api.nvim_open_term(buf, {})
@@ -1194,4 +1196,144 @@ describe('nvim_open_term()', function()
check_buffer_lines(86, 99)
check_common()
end)
+
+ describe('when window height', function()
+ before_each(function()
+ feed('<C-W>lGV4kdgg')
+ screen:try_resize(30, 20)
+ command('botright 9new | wincmd p')
+ exec_lua(function()
+ vim.g.chan = vim.api.nvim_open_term(buf, {})
+ vim.cmd('$')
+ end)
+ screen:expect([[
+ │{100:TEST} 88 |
+ {1:~ }│{100:TEST} 89 |
+ {1:~ }│{100:TEST} 90 |
+ {1:~ }│{100:TEST} 91 |
+ {1:~ }│{100:TEST} 92 |
+ {1:~ }│{100:TEST} 93 |
+ {1:~ }│{100:TEST} 94 |
+ {1:~ }│^ |
+ {2:[No Name] }{102:[Scratch] [-] }|
+ |
+ {1:~ }|*8
+ {2:[No Name] }|
+ |
+ ]])
+ check_buffer_lines(0, 94)
+ end)
+
+ local send_cmd = 'call chansend(g:chan, @")'
+
+ describe('increases in the same refresh cycle as outputting lines', function()
+ --- @type string[][]
+ local perms = t.concat_tables(
+ t.permutations({ 'resize +2', send_cmd }),
+ t.permutations({ 'resize +4', 'resize -2', send_cmd }),
+ t.permutations({ 'resize +6', 'resize -4', send_cmd })
+ )
+ assert(#perms == 2 + 6 + 6)
+ local screen_final = [[
+ │{100:TEST} 91 |
+ {1:~ }│{100:TEST} 92 |
+ {1:~ }│{100:TEST} 93 |
+ {1:~ }│{100:TEST} 94 |
+ {1:~ }│{100:TEST} 95 |
+ {1:~ }│{100:TEST} 96 |
+ {1:~ }│{100:TEST} 97 |
+ {1:~ }│{100:TEST} 98 |
+ {1:~ }│{100:TEST} 99 |
+ {1:~ }│^ |
+ {2:[No Name] }{102:[Scratch] [-] }|
+ |
+ {1:~ }|*6
+ {2:[No Name] }|
+ |
+ ]]
+
+ for i, perm in ipairs(perms) do
+ it(('permutation %d'):format(i), function()
+ exec_lua(function()
+ for _, cmd in ipairs(perm) do
+ vim.cmd(cmd)
+ end
+ end)
+ screen:expect(screen_final)
+ check_buffer_lines(0, 99)
+ end)
+ end
+ end)
+
+ describe('decreases in the same refresh cycle as outputting lines', function()
+ --- @type string[][]
+ local perms = t.concat_tables(
+ t.permutations({ 'resize -2', send_cmd }),
+ t.permutations({ 'resize -4', 'resize +2', send_cmd }),
+ t.permutations({ 'resize -6', 'resize +4', send_cmd })
+ )
+ assert(#perms == 2 + 6 + 6)
+ local screen_final = [[
+ │{100:TEST} 95 |
+ {1:~ }│{100:TEST} 96 |
+ {1:~ }│{100:TEST} 97 |
+ {1:~ }│{100:TEST} 98 |
+ {1:~ }│{100:TEST} 99 |
+ {1:~ }│^ |
+ {2:[No Name] }{102:[Scratch] [-] }|
+ |
+ {1:~ }|*10
+ {2:[No Name] }|
+ |
+ ]]
+
+ for i, perm in ipairs(perms) do
+ it(('permutation %d'):format(i), function()
+ exec_lua(function()
+ for _, cmd in ipairs(perm) do
+ vim.cmd(cmd)
+ end
+ end)
+ screen:expect(screen_final)
+ check_buffer_lines(0, 99)
+ end)
+ end
+ end)
+
+ describe("decreases by more than 'scrollback'", function()
+ before_each(function()
+ api.nvim_set_option_value('scrollback', 4, { buf = buf })
+ check_buffer_lines(84, 94)
+ end)
+
+ local perms = {
+ { send_cmd, 'resize -6' },
+ { 'resize -6', send_cmd },
+ { send_cmd, 'resize +6', 'resize -12' },
+ { 'resize +6', send_cmd, 'resize -12' },
+ { 'resize +6', 'resize -12', send_cmd },
+ }
+ local screen_final = [[
+ │{100:TEST} 99 |
+ {1:~ }│^ |
+ {2:[No Name] }{102:[Scratch] [-] }|
+ |
+ {1:~ }|*14
+ {2:[No Name] }|
+ |
+ ]]
+
+ for i, perm in ipairs(perms) do
+ it(('permutation %d'):format(i), function()
+ exec_lua(function()
+ for _, cmd in ipairs(perm) do
+ vim.cmd(cmd)
+ end
+ end)
+ screen:expect(screen_final)
+ check_buffer_lines(95, 99)
+ end)
+ end
+ end)
+ end)
end)
diff --git a/test/testutil.lua b/test/testutil.lua
@@ -646,6 +646,29 @@ function M.concat_tables(...)
return ret
end
+--- Get all permutations of an array.
+---
+--- @param arr any[]
+--- @return any[][]
+function M.permutations(arr)
+ local res = {} --- @type any[][]
+ --- @param a any[]
+ --- @param n integer
+ local function gen(a, n)
+ if n == 0 then
+ res[#res + 1] = M.shallowcopy(a)
+ return
+ end
+ for i = 1, n do
+ a[n], a[i] = a[i], a[n]
+ gen(a, n - 1)
+ a[n], a[i] = a[i], a[n]
+ end
+ end
+ gen(M.shallowcopy(arr), #arr)
+ return res
+end
+
--- @param str string
--- @param leave_indent? integer
--- @return string
