vim-patch:9.1.0180: Cursor pos wrong when double-width chars are concealed (#27862)

Problem:  Cursor pos wrong when double-width chars are concealed.
Solution: Advance one more virtual column for a double-width char.
          Run some tests with both 'wrap' and 'nowrap' (zeertzjq).

closes: vim/vim#14197

https://github.com/vim/vim/commit/010e1539d67442cc69a97bef6453efaf849d0db3

3 files changed, 248 insertions, 46 deletions

diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 2f541a8a21..dfe3dbca50 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -2403,6 +2403,13 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int col_rows, s
           } else {
             mb_schar = schar_from_ascii(' ');
           }
+
+          if (utf_char2cells(mb_c) > 1) {
+            // When the first char to be concealed is double-width,
+            // need to advance one more virtual column.
+            wlv.n_extra++;
+          }
+
           mb_c = schar_get_first_codepoint(mb_schar);
 
           prev_syntax_id = syntax_seqnr;
@@ -2739,11 +2746,21 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int col_rows, s
       wlv.off++;
       wlv.col++;
     } else if (wp->w_p_cole > 0 && is_concealing) {
+      bool concealed_wide = utf_char2cells(mb_c) > 1;
+
       wlv.skip_cells--;
       wlv.vcol_off_co++;
+      if (concealed_wide) {
+        // When a double-width char is concealed,
+        // need to advance one more virtual column.
+        wlv.vcol++;
+        wlv.vcol_off_co++;
+      }
+
       if (wlv.n_extra > 0) {
         wlv.vcol_off_co += wlv.n_extra;
       }
+
       if (is_wrapped) {
         // Special voodoo required if 'wrap' is on.
         //
@@ -2764,7 +2781,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int col_rows, s
           wlv.n_attr = 0;
         }
 
-        if (utf_char2cells(mb_c) > 1) {
+        if (concealed_wide) {
           // Need to fill two screen columns.
           wlv.boguscols++;
           wlv.col++;
diff --git a/test/functional/legacy/conceal_spec.lua b/test/functional/legacy/conceal_spec.lua
index 63ec644a10..e2cc3b23df 100644
--- a/test/functional/legacy/conceal_spec.lua
+++ b/test/functional/legacy/conceal_spec.lua
@@ -4,6 +4,7 @@ local clear = helpers.clear
 local command = helpers.command
 local exec = helpers.exec
 local feed = helpers.feed
+local api = helpers.api
 
 local expect_pos = function(row, col)
   return helpers.eq({ row, col }, helpers.eval('[screenrow(), screencol()]'))
@@ -633,13 +634,13 @@ describe('Conceal', function()
     expect_pos(9, 26)
   end)
 
-  -- oldtest: Test_conceal_virtualedit_after_eol()
-  it('cursor drawn at correct column with virtualedit', function()
-    local screen = Screen.new(75, 3)
+  local function test_conceal_virtualedit_after_eol(wrap)
+    local screen = Screen.new(60, 3)
     screen:set_default_attr_ids({
       [0] = { bold = true, foreground = Screen.colors.Blue }, -- NonText
     })
     screen:attach()
+    api.nvim_set_option_value('wrap', wrap, {})
     exec([[
       call setline(1, 'abcdefgh|hidden|ijklmnpop')
       syntax match test /|hidden|/ conceal
@@ -647,43 +648,53 @@ describe('Conceal', function()
       normal! $
     ]])
     screen:expect([[
-      abcdefghijklmnpo^p                                                          |
-      {0:~                                                                          }|
-                                                                                 |
+      abcdefghijklmnpo^p                                           |
+      {0:~                                                           }|
+                                                                  |
     ]])
     feed('l')
     screen:expect([[
-      abcdefghijklmnpop^                                                          |
-      {0:~                                                                          }|
-                                                                                 |
+      abcdefghijklmnpop^                                           |
+      {0:~                                                           }|
+                                                                  |
     ]])
     feed('l')
     screen:expect([[
-      abcdefghijklmnpop ^                                                         |
-      {0:~                                                                          }|
-                                                                                 |
+      abcdefghijklmnpop ^                                          |
+      {0:~                                                           }|
+                                                                  |
     ]])
     feed('l')
     screen:expect([[
-      abcdefghijklmnpop  ^                                                        |
-      {0:~                                                                          }|
-                                                                                 |
+      abcdefghijklmnpop  ^                                         |
+      {0:~                                                           }|
+                                                                  |
     ]])
     feed('rr')
     screen:expect([[
-      abcdefghijklmnpop  ^r                                                       |
-      {0:~                                                                          }|
-                                                                                 |
+      abcdefghijklmnpop  ^r                                        |
+      {0:~                                                           }|
+                                                                  |
     ]])
+  end
+
+  -- oldtest: Test_conceal_virtualedit_after_eol()
+  describe('cursor drawn at correct column with virtualedit', function()
+    it('with wrapping', function()
+      test_conceal_virtualedit_after_eol(true)
+    end)
+    it('without wrapping', function()
+      test_conceal_virtualedit_after_eol(false)
+    end)
   end)
 
-  -- oldtest: Test_conceal_virtualedit_after_eol_rightleft()
-  it('cursor drawn correctly with virtualedit and rightleft', function()
-    local screen = Screen.new(75, 3)
+  local function test_conceal_virtualedit_after_eol_rightleft(wrap)
+    local screen = Screen.new(60, 3)
     screen:set_default_attr_ids({
       [0] = { bold = true, foreground = Screen.colors.Blue }, -- NonText
     })
     screen:attach()
+    api.nvim_set_option_value('wrap', wrap, {})
     exec([[
       call setline(1, 'abcdefgh|hidden|ijklmnpop')
       syntax match test /|hidden|/ conceal
@@ -691,33 +702,141 @@ describe('Conceal', function()
       normal! $
     ]])
     screen:expect([[
-                                                                ^popnmlkjihgfedcba|
-      {0:                                                                          ~}|
-                                                                                 |
+                                                 ^popnmlkjihgfedcba|
+      {0:                                                           ~}|
+                                                                  |
     ]])
     feed('h')
     screen:expect([[
-                                                               ^ popnmlkjihgfedcba|
-      {0:                                                                          ~}|
-                                                                                 |
+                                                ^ popnmlkjihgfedcba|
+      {0:                                                           ~}|
+                                                                  |
     ]])
     feed('h')
     screen:expect([[
-                                                              ^  popnmlkjihgfedcba|
-      {0:                                                                          ~}|
-                                                                                 |
+                                               ^  popnmlkjihgfedcba|
+      {0:                                                           ~}|
+                                                                  |
     ]])
     feed('h')
     screen:expect([[
-                                                             ^   popnmlkjihgfedcba|
-      {0:                                                                          ~}|
-                                                                                 |
+                                              ^   popnmlkjihgfedcba|
+      {0:                                                           ~}|
+                                                                  |
     ]])
     feed('rr')
     screen:expect([[
-                                                             ^r  popnmlkjihgfedcba|
-      {0:                                                                          ~}|
-                                                                                 |
+                                              ^r  popnmlkjihgfedcba|
+      {0:                                                           ~}|
+                                                                  |
+    ]])
+  end
+
+  -- oldtest: Test_conceal_virtualedit_after_eol_rightleft()
+  describe('cursor drawn correctly with virtualedit and rightleft', function()
+    it('with wrapping', function()
+      test_conceal_virtualedit_after_eol_rightleft(true)
+    end)
+    it('without wrapping', function()
+      test_conceal_virtualedit_after_eol_rightleft(false)
+    end)
+  end)
+
+  local function test_conceal_double_width(wrap)
+    local screen = Screen.new(60, 4)
+    screen:set_default_attr_ids({
+      [0] = { bold = true, foreground = Screen.colors.Blue },
+      [1] = { background = Screen.colors.DarkGrey, foreground = Screen.colors.LightGrey },
+      [2] = { background = Screen.colors.LightRed },
+    })
+    screen:attach()
+    api.nvim_set_option_value('wrap', wrap, {})
+    exec([[
+      call setline(1, ['aaaaa口=口bbbbb口=口ccccc', 'foobar'])
+      syntax match test /口=口/ conceal cchar=β
+      set conceallevel=2 concealcursor=n colorcolumn=30
+      normal! $
+    ]])
+    screen:expect([[
+      aaaaa{1:β}bbbbb{1:β}cccc^c            {2: }                              |
+      foobar                       {2: }                              |
+      {0:~                                                           }|
+                                                                  |
+    ]])
+    feed('gM')
+    screen:expect([[
+      aaaaa{1:β}bb^bbb{1:β}ccccc            {2: }                              |
+      foobar                       {2: }                              |
+      {0:~                                                           }|
+                                                                  |
+    ]])
+    command('set conceallevel=3')
+    screen:expect([[
+      aaaaabb^bbbccccc              {2: }                              |
+      foobar                       {2: }                              |
+      {0:~                                                           }|
+                                                                  |
+    ]])
+    feed('$')
+    screen:expect([[
+      aaaaabbbbbcccc^c              {2: }                              |
+      foobar                       {2: }                              |
+      {0:~                                                           }|
+                                                                  |
+    ]])
+  end
+
+  -- oldtest: Test_conceal_double_width()
+  describe('cursor drawn correctly when double-width chars are concealed', function()
+    it('with wrapping', function()
+      test_conceal_double_width(true)
+    end)
+    it('without wrapping', function()
+      test_conceal_double_width(false)
+    end)
+  end)
+
+  -- oldtest: Test_conceal_double_width_wrap()
+  it('line wraps correctly when double-width chars are concealed', function()
+    local screen = Screen.new(20, 4)
+    screen:set_default_attr_ids({
+      [0] = { bold = true, foreground = Screen.colors.Blue },
+      [1] = { background = Screen.colors.DarkGrey, foreground = Screen.colors.LightGrey },
+      [2] = { background = Screen.colors.LightRed },
+    })
+    screen:attach()
+    exec([[
+      call setline(1, 'aaaaaaaaaa口=口bbbbbbbbbb口=口cccccccccc')
+      syntax match test /口=口/ conceal cchar=β
+      set conceallevel=2 concealcursor=n
+      normal! $
+    ]])
+    screen:expect([[
+      aaaaaaaaaa{1:β}bbbbb    |
+      bbbbb{1:β}ccccccccc^c    |
+      {0:~                   }|
+                          |
+    ]])
+    feed('gM')
+    screen:expect([[
+      aaaaaaaaaa{1:β}bbbbb    |
+      ^bbbbb{1:β}cccccccccc    |
+      {0:~                   }|
+                          |
+    ]])
+    command('set conceallevel=3')
+    screen:expect([[
+      aaaaaaaaaabbbbb     |
+      ^bbbbbcccccccccc     |
+      {0:~                   }|
+                          |
+    ]])
+    feed('$')
+    screen:expect([[
+      aaaaaaaaaabbbbb     |
+      bbbbbccccccccc^c     |
+      {0:~                   }|
+                          |
     ]])
   end)
 end)
diff --git a/test/old/testdir/test_conceal.vim b/test/old/testdir/test_conceal.vim
index 94d5d1d470..52b0661f85 100644
--- a/test/old/testdir/test_conceal.vim
+++ b/test/old/testdir/test_conceal.vim
@@ -439,7 +439,7 @@ func Test_conceal_mouse_click()
   call Ntest_setmouse(1, 19)
   call feedkeys("\<LeftMouse>", "tx")
   call assert_equal([0, 1, 23, 0, 23], getcurpos())
-  " click after end of line puts cursor there without 'virtualedit'
+  " click after end of line puts cursor there with 'virtualedit'
   call Ntest_setmouse(1, 20)
   call feedkeys("\<LeftMouse>", "tx")
   call assert_equal([0, 1, 24, 0, 24], getcurpos())
@@ -462,10 +462,9 @@ endfunc
 
 " Test that cursor is drawn at the correct column when it is after end of the
 " line with 'virtualedit' and concealing.
-func Test_conceal_virtualedit_after_eol()
-  CheckScreendump
-
-  let code =<< trim [CODE]
+func Run_test_conceal_virtualedit_after_eol(wrap)
+  let code =<< trim eval [CODE]
+    let &wrap = {a:wrap}
     call setline(1, 'abcdefgh|hidden|ijklmnpop')
     syntax match test /|hidden|/ conceal
     set conceallevel=2 concealcursor=n virtualedit=all
@@ -487,12 +486,17 @@ func Test_conceal_virtualedit_after_eol()
   call StopVimInTerminal(buf)
 endfunc
 
-" Same as Test_conceal_virtualedit_after_eol(), but with 'rightleft' set.
-func Test_conceal_virtualedit_after_eol_rightleft()
-  CheckFeature rightleft
+func Test_conceal_virtualedit_after_eol()
   CheckScreendump
 
-  let code =<< trim [CODE]
+  call Run_test_conceal_virtualedit_after_eol(1)
+  call Run_test_conceal_virtualedit_after_eol(0)
+endfunc
+
+" Same as Run_test_conceal_virtualedit_after_eol(), but with 'rightleft'.
+func Run_test_conceal_virtualedit_after_eol_rightleft(wrap)
+  let code =<< trim eval [CODE]
+    let &wrap = {a:wrap}
     call setline(1, 'abcdefgh|hidden|ijklmnpop')
     syntax match test /|hidden|/ conceal
     set conceallevel=2 concealcursor=n virtualedit=all rightleft
@@ -514,4 +518,66 @@ func Test_conceal_virtualedit_after_eol_rightleft()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_conceal_virtualedit_after_eol_rightleft()
+  CheckFeature rightleft
+  CheckScreendump
+
+  call Run_test_conceal_virtualedit_after_eol_rightleft(1)
+  call Run_test_conceal_virtualedit_after_eol_rightleft(0)
+endfunc
+
+" Test that cursor position is correct when double-width chars are concealed.
+func Run_test_conceal_double_width(wrap)
+  let code =<< trim eval [CODE]
+    let &wrap = {a:wrap}
+    call setline(1, ['aaaaa口=口bbbbb口=口ccccc', 'foobar'])
+    syntax match test /口=口/ conceal cchar=β
+    set conceallevel=2 concealcursor=n colorcolumn=30
+    normal! $
+  [CODE]
+  call writefile(code, 'XTest_conceal_double_width', 'D')
+  let buf = RunVimInTerminal('-S XTest_conceal_double_width', {'rows': 4})
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_1', {})
+  call term_sendkeys(buf, "gM")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_2', {})
+  call term_sendkeys(buf, ":set conceallevel=3\<CR>")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_3', {})
+  call term_sendkeys(buf, "$")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_4', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+endfunc
+
+func Test_conceal_double_width()
+  CheckScreendump
+
+  call Run_test_conceal_double_width(1)
+  call Run_test_conceal_double_width(0)
+endfunc
+
+" Test that line wrapping is correct when double-width chars are concealed.
+func Test_conceal_double_width_wrap()
+  CheckScreendump
+
+  let code =<< trim [CODE]
+    call setline(1, 'aaaaaaaaaa口=口bbbbbbbbbb口=口cccccccccc')
+    syntax match test /口=口/ conceal cchar=β
+    set conceallevel=2 concealcursor=n
+    normal! $
+  [CODE]
+  call writefile(code, 'XTest_conceal_double_width_wrap', 'D')
+  let buf = RunVimInTerminal('-S XTest_conceal_double_width_wrap', {'rows': 4, 'cols': 20})
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_wrap_1', {})
+  call term_sendkeys(buf, "gM")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_wrap_2', {})
+  call term_sendkeys(buf, ":set conceallevel=3\<CR>")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_wrap_3', {})
+  call term_sendkeys(buf, "$")
+  call VerifyScreenDump(buf, 'Test_conceal_double_width_wrap_4', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab