fix(plines): count 'showbreak' in EOL inline virt_text in line size (#35921)

src/nvim/plines.c

@@ -456,8 +456,8 @@ int linesize_regular(CharsizeArg *const csarg, int vcol_arg, colnr_T const len)
 
   // Check for inline virtual text after the end of the line.
   if (len == MAXCOL && csarg->virt_row >= 0 && *ci.ptr == NUL) {
-    (void)charsize_regular(csarg, ci.ptr, vcol_arg, ci.chr.value);
+    int head = charsize_regular(csarg, ci.ptr, vcol_arg, ci.chr.value).head;
-    vcol += csarg->cur_text_width_left + csarg->cur_text_width_right;
+    vcol += csarg->cur_text_width_left + csarg->cur_text_width_right + head;
     vcol_arg = vcol > MAXCOL ? MAXCOL : (int)vcol;
   }
 

test/functional/ui/decorations_spec.lua

@@ -3590,6 +3590,8 @@ describe('decorations: inline virtual text', function()
       [19] = { background = Screen.colors.Yellow, foreground = Screen.colors.SlateBlue },
       [20] = { background = Screen.colors.LightGrey, foreground = Screen.colors.SlateBlue },
       [21] = { reverse = true, foreground = Screen.colors.SlateBlue },
+      [22] = { background = Screen.colors.Gray90 },
+      [23] = { background = Screen.colors.Gray90, foreground = Screen.colors.Blue, bold = true },
     }
 
     ns = api.nvim_create_namespace 'test'
@@ -5659,6 +5661,58 @@ describe('decorations: inline virtual text', function()
                                                         |
     ]])
   end)
+
+  it('line size is correct with inline virt text at EOL and showbreak', function()
+    screen:try_resize(50, 8)
+    insert(('0123456789'):rep(5) .. '\nfoo\nbar')
+    api.nvim_buf_set_extmark(0, ns, 0, 50, { virt_text = { { ('x'):rep(49), 'ErrorMsg' } }, virt_text_pos = 'inline' })
+
+    command([[set showbreak=>\  cursorline]])
+    screen:expect([[
+      01234567890123456789012345678901234567890123456789|
+      {1:> }{4:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}|
+      {1:> }{4:x}                                               |
+      foo                                               |
+      {22:ba^r                                               }|
+      {1:~                                                 }|*2
+                                                        |
+    ]])
+    eq(3, api.nvim_win_text_height(0, { start_row = 0, end_row = 0 }).all)
+
+    feed('gg$x<C-O>')
+    screen:expect([[
+      0123456789012345678901234567890123456789012345678{4:x}|
+      {1:> }{4:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}|
+      foo                                               |
+      {22:ba^r                                               }|
+      {1:~                                                 }|*3
+                                                        |
+    ]])
+    eq(2, api.nvim_win_text_height(0, { start_row = 0, end_row = 0 }).all)
+
+    command('set list listchars=eol:$')
+    screen:expect([[
+      0123456789012345678901234567890123456789012345678{4:x}|
+      {1:> }{4:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}|
+      {1:> $}                                               |
+      foo{1:$}                                              |
+      {22:ba^r}{23:$}{22:                                              }|
+      {1:~                                                 }|*2
+                                                        |
+    ]])
+    eq(3, api.nvim_win_text_height(0, { start_row = 0, end_row = 0 }).all)
+
+    feed('gg$x<C-O>')
+    screen:expect([[
+      012345678901234567890123456789012345678901234567{4:xx}|
+      {1:> }{4:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}{1:$}|
+      foo{1:$}                                              |
+      {22:ba^r}{23:$}{22:                                              }|
+      {1:~                                                 }|*3
+                                                        |
+    ]])
+    eq(2, api.nvim_win_text_height(0, { start_row = 0, end_row = 0 }).all)
+  end)
 end)
 
 describe('decorations: virtual lines', function()