fix(shada): don't add '0' mark if f0 in 'shada'

src/nvim/shada.c

@@ -2559,9 +2559,9 @@ static ShaDaWriteResult shada_write(FileDescriptor *const sd_writer,
     }
   }
 
-  // Update numbered marks: '0' should be replaced with the current position,
-  // '9' should be removed and all other marks shifted.
-  if (!ignore_buf(curbuf, &removable_bufs) && curwin->w_cursor.lnum != 0) {
+  // Update numbered marks: replace '0 mark with the current position,
+  // remove '9 and shift all other marks. Skip if f0 in 'shada'.
+  if (dump_global_marks && !ignore_buf(curbuf, &removable_bufs) && curwin->w_cursor.lnum != 0) {
     replace_numbered_mark(wms, 0, (PossiblyFreedShadaEntry) {
       .can_free_entry = false,
       .data = {

test/functional/shada/marks_spec.lua

@@ -51,29 +51,115 @@ describe('ShaDa support code', function()
     eq(2, nvim_current_line())
   end)
 
-  it('does not dump global mark with `f0` in shada', function()
+  it('can dump and read back numbered marks', function()
+    local function move(cmd)
+      feed(cmd)
+      nvim_command('wshada')
+    end
+    nvim_command('edit ' .. testfilename)
+    move('l')
+    move('l')
+    move('j')
+    move('l')
+    move('l')
+    nvim_command('edit ' .. testfilename_2)
+    move('l')
+    move('l')
+    move('j')
+    move('l')
+    move('l')
+    -- we have now populated marks 0 through 9
+    nvim_command('edit ' .. testfilename)
+    feed('gg0')
+    -- during shada save on exit, mark 0 will become the current position,
+    -- 9 will be removed, and all other marks shifted
+    expect_exit(nvim_command, 'qall')
+    reset()
+    nvim_command('edit ' .. testfilename)
+    nvim_command('edit ' .. testfilename_2)
+    local marklist = fn.getmarklist()
+    for _, mark in ipairs(marklist) do
+      mark.file = fn.fnamemodify(mark.file, ':t')
+    end
+    eq({
+      {
+        file = testfilename,
+        mark = "'0",
+        pos = { 1, 1, 1, 0 },
+      },
+      {
+        file = testfilename_2,
+        mark = "'1",
+        pos = { 2, 2, 5, 0 },
+      },
+      {
+        file = testfilename_2,
+        mark = "'2",
+        pos = { 2, 2, 4, 0 },
+      },
+      {
+        file = testfilename_2,
+        mark = "'3",
+        pos = { 2, 2, 3, 0 },
+      },
+      {
+        file = testfilename_2,
+        mark = "'4",
+        pos = { 2, 1, 3, 0 },
+      },
+      {
+        file = testfilename_2,
+        mark = "'5",
+        pos = { 2, 1, 2, 0 },
+      },
+      {
+        file = testfilename,
+        mark = "'6",
+        pos = { 1, 2, 5, 0 },
+      },
+      {
+        file = testfilename,
+        mark = "'7",
+        pos = { 1, 2, 4, 0 },
+      },
+      {
+        file = testfilename,
+        mark = "'8",
+        pos = { 1, 2, 3, 0 },
+      },
+      {
+        file = testfilename,
+        mark = "'9",
+        pos = { 1, 1, 3, 0 },
+      },
+    }, marklist)
+  end)
+
+  it('does not dump global or numbered marks with `f0` in shada', function()
     nvim_command('set shada+=f0')
     nvim_command('edit ' .. testfilename)
     nvim_command('mark A')
     nvim_command('2')
-    nvim_command('kB')
     nvim_command('wshada')
     reset()
     nvim_command('language C')
     eq('Vim(normal):E20: Mark not set', exc_exec('normal! `A'))
+    eq('Vim(normal):E20: Mark not set', exc_exec('normal! `0'))
   end)
 
-  it("does read back global mark even with `'0` and `f0` in shada", function()
+  it("restores global and numbered marks even with `'0` and `f0` in shada", function()
     nvim_command('edit ' .. testfilename)
     nvim_command('mark A')
     nvim_command('2')
-    nvim_command('kB')
     nvim_command('wshada')
     reset("set shada='0,f0")
     nvim_command('language C')
     nvim_command('normal! `A')
     eq(testfilename, fn.fnamemodify(api.nvim_buf_get_name(0), ':t'))
     eq(1, nvim_current_line())
+    nvim_command('normal! `0')
+    eq(testfilename, fn.fnamemodify(api.nvim_buf_get_name(0), ':t'))
+    eq(2, nvim_current_line())
   end)
 
   it('is able to dump and read back local mark', function()