terminal: 'scrollback'

Closes #2637

4 files changed, 111 insertions, 30 deletions

diff --git a/test/functional/terminal/edit_spec.lua b/test/functional/terminal/edit_spec.lua
index 8edcfa56b7..9795e7957d 100644
--- a/test/functional/terminal/edit_spec.lua
+++ b/test/functional/terminal/edit_spec.lua
@@ -31,45 +31,40 @@ describe(':edit term://*', function()
     eq(termopen_runs[1], termopen_runs[1]:match('^term://.//%d+:$'))
   end)
 
-  it('runs TermOpen early enough to respect terminal_scrollback_buffer_size', function()
+  it("runs TermOpen early enough to set buffer-local 'scrollback'", function()
     local columns, lines = 20, 4
     local scr = get_screen(columns, lines)
     local rep = 'a'
     meths.set_option('shellcmdflag', 'REP ' .. rep)
-    local rep_size = rep:byte()
+    local rep_size = rep:byte()  -- 'a' => 97
     local sb = 10
-    local gsb = 20
-    meths.set_var('terminal_scrollback_buffer_size', gsb)
-    command('autocmd TermOpen * :let b:terminal_scrollback_buffer_size = '
-            .. tostring(sb))
+    command('autocmd TermOpen * :setlocal scrollback='..tostring(sb))
     command('edit term://foobar')
+
     local bufcontents = {}
     local winheight = curwinmeths.get_height()
-    -- I have no idea why there is + 4 needed. But otherwise it works fine with
-    -- different scrollbacks.
-    local shift = -4
-    local buf_cont_start = rep_size - 1 - sb - winheight - shift
-    local bufline = function(i) return ('%d: foobar'):format(i) end
+    local buf_cont_start = rep_size - sb - winheight + 2
+    local function bufline (i)
+      return ('%d: foobar'):format(i)
+    end
     for i = buf_cont_start,(rep_size - 1) do
       bufcontents[#bufcontents + 1] = bufline(i)
     end
     bufcontents[#bufcontents + 1] = ''
     bufcontents[#bufcontents + 1] = '[Process exited 0]'
-    -- Do not ask me why displayed screen is one line *before* buffer
-    -- contents: buffer starts with 87:, screen with 86:.
+
     local exp_screen = '\n'
-    local did_cursor = false
-    for i = 0,(winheight - 1) do
-      local line = bufline(buf_cont_start + i - 1)
+    for i = 1,(winheight - 1) do
+      local line = bufcontents[#bufcontents - winheight + i]
       exp_screen = (exp_screen
-                    .. (did_cursor and '' or '^')
                     .. line
                     .. (' '):rep(columns - #line)
                     .. '|\n')
-      did_cursor = true
     end
-    exp_screen = exp_screen .. (' '):rep(columns) .. '|\n'
+    exp_screen = exp_screen..'^[Process exited 0]  |\n'
+
+    exp_screen = exp_screen..(' '):rep(columns)..'|\n'
     scr:expect(exp_screen)
-    eq(bufcontents, curbufmeths.get_lines(1, -1, true))
+    eq(bufcontents, curbufmeths.get_lines(0, -1, true))
   end)
 end)
diff --git a/test/functional/terminal/ex_terminal_spec.lua b/test/functional/terminal/ex_terminal_spec.lua
index 7c391db18c..dc2535bade 100644
--- a/test/functional/terminal/ex_terminal_spec.lua
+++ b/test/functional/terminal/ex_terminal_spec.lua
@@ -20,22 +20,18 @@ describe(':terminal', function()
     source([[
       echomsg "msg1"
       echomsg "msg2"
+      echomsg "msg3"
     ]])
     -- Invoke a command that emits frequent terminal activity.
     execute([[terminal while true; do echo X; done]])
     helpers.feed([[<C-\><C-N>]])
-    screen:expect([[
-      X                                                 |
-      X                                                 |
-      ^X                                                 |
-                                                        |
-    ]])
+    wait()
     helpers.sleep(10)  -- Let some terminal activity happen.
     execute("messages")
     screen:expect([[
-      X                                                 |
       msg1                                              |
       msg2                                              |
+      msg3                                              |
       Press ENTER or type command to continue^           |
     ]])
   end)
diff --git a/test/functional/terminal/helpers.lua b/test/functional/terminal/helpers.lua
index ae5e6d4b1f..8c31a300dd 100644
--- a/test/functional/terminal/helpers.lua
+++ b/test/functional/terminal/helpers.lua
@@ -37,7 +37,6 @@ local default_command = '["'..nvim_dir..'/tty-test'..'"]'
 local function screen_setup(extra_height, command)
   nvim('command', 'highlight TermCursor cterm=reverse')
   nvim('command', 'highlight TermCursorNC ctermbg=11')
-  nvim('set_var', 'terminal_scrollback_buffer_size', 10)
   if not extra_height then extra_height = 0 end
   if not command then command = default_command end
   local screen = Screen.new(50, 7 + extra_height)
@@ -58,7 +57,9 @@ local function screen_setup(extra_height, command)
   -- tty-test puts the terminal into raw mode and echoes all input. tests are
   -- done by feeding it with terminfo codes to control the display and
   -- verifying output with screen:expect.
-  execute('enew | call termopen('..command..') | startinsert')
+  execute('enew | call termopen('..command..')')
+  execute('setlocal scrollback=10')
+  execute('startinsert')
   if command == default_command then
     -- wait for "tty ready" to be printed before each test or the terminal may
     -- still be in canonical mode(will echo characters for example)
diff --git a/test/functional/terminal/scrollback_spec.lua b/test/functional/terminal/scrollback_spec.lua
index d60819af65..74d44649a8 100644
--- a/test/functional/terminal/scrollback_spec.lua
+++ b/test/functional/terminal/scrollback_spec.lua
@@ -3,7 +3,11 @@ local helpers = require('test.functional.helpers')(after_each)
 local thelpers = require('test.functional.terminal.helpers')
 local clear, eq, curbuf = helpers.clear, helpers.eq, helpers.curbuf
 local feed, nvim_dir, execute = helpers.feed, helpers.nvim_dir, helpers.execute
+local eval = helpers.eval
+local command = helpers.command
 local wait = helpers.wait
+local retry = helpers.retry
+local curbufmeths = helpers.curbufmeths
 local feed_data = thelpers.feed_data
 
 if helpers.pending_win32(pending) then return end
@@ -20,7 +24,7 @@ describe('terminal scrollback', function()
     screen:detach()
   end)
 
-  describe('when the limit is crossed', function()
+  describe('when the limit is exceeded', function()
     before_each(function()
       local lines = {}
       for i = 1, 30 do
@@ -359,3 +363,88 @@ describe('terminal prints more lines than the screen height and exits', function
   end)
 end)
 
+describe("'scrollback' option", function()
+  before_each(function()
+    clear()
+  end)
+
+  local function expect_lines(expected)
+    local actual = eval("line('$')")
+    if expected ~= actual then
+    error('expected: '..expected..', actual: '..tostring(actual))
+    end
+  end
+
+  it('set to 0 behaves as 1', function()
+    local screen = thelpers.screen_setup(nil, "['sh']", 30)
+
+    curbufmeths.set_option('scrollback', 0)
+    feed_data('for i in $(seq 1 30); do echo "line$i"; done\n')
+    screen:expect('line30                        ', nil, nil, nil, true)
+    retry(nil, nil, function() expect_lines(7) end)
+
+    screen:detach()
+  end)
+
+  it('deletes lines (only) if necessary', function()
+    local screen = thelpers.screen_setup(nil, "['sh']", 30)
+
+    curbufmeths.set_option('scrollback', 200)
+
+    -- Wait for prompt.
+    screen:expect('$', nil, nil, nil, true)
+
+    wait()
+    feed_data('for i in $(seq 1 30); do echo "line$i"; done\n')
+
+    screen:expect('line30                        ', nil, nil, nil, true)
+
+    retry(nil, nil, function() expect_lines(33) end)
+    curbufmeths.set_option('scrollback', 10)
+    wait()
+    retry(nil, nil, function() expect_lines(16) end)
+    curbufmeths.set_option('scrollback', 10000)
+    eq(16, eval("line('$')"))
+    -- Terminal job data is received asynchronously, may happen before the
+    -- 'scrollback' option is synchronized with the internal sb_buffer.
+    command('sleep 100m')
+    feed_data('for i in $(seq 1 40); do echo "line$i"; done\n')
+
+    screen:expect('line40                        ', nil, nil, nil, true)
+
+    retry(nil, nil, function() expect_lines(58) end)
+    -- Verify off-screen state
+    eq('line35', eval("getline(line('w0') - 1)"))
+    eq('line26', eval("getline(line('w0') - 10)"))
+
+    screen:detach()
+  end)
+
+  it('defaults to 1000', function()
+    execute('terminal')
+    eq(1000, curbufmeths.get_option('scrollback'))
+  end)
+
+  it('error if set to invalid values', function()
+    local status, rv = pcall(command, 'set scrollback=-2')
+    eq(false, status)  -- assert failure
+    eq('E474:', string.match(rv, "E%d*:"))
+
+    status, rv = pcall(command, 'set scrollback=100001')
+    eq(false, status)  -- assert failure
+    eq('E474:', string.match(rv, "E%d*:"))
+  end)
+
+  it('defaults to -1 on normal buffers', function()
+    execute('new')
+    eq(-1, curbufmeths.get_option('scrollback'))
+  end)
+
+  it('error if set on a normal buffer', function()
+    command('new')
+    execute('set scrollback=42')
+    feed('<CR>')
+    eq('E474:', string.match(eval("v:errmsg"), "E%d*:"))
+  end)
+
+end)