fix(vim.opt): Fix #14668 Now correctly handles unescaped commas in isfname style

runtime/lua/vim/_meta.lua

@@ -405,12 +405,46 @@ local convert_value_to_lua = (function()
     [OptionTypes.NUMBER] = function(_, value) return value end,
     [OptionTypes.STRING] = function(_, value) return value end,
 
-    [OptionTypes.ARRAY] = function(_, value)
+    [OptionTypes.ARRAY] = function(info, value)
       if type(value) == "table" then
-        value = remove_duplicate_values(value)
+        if not info.allows_duplicates then
+          value = remove_duplicate_values(value)
+        end
+
         return value
       end
 
+      -- Handles unescaped commas in a list.
+      if string.find(value, ",,,") then
+        local comma_split = vim.split(value, ",,,")
+        local left = comma_split[1]
+        local right = comma_split[2]
+
+        local result = {}
+        vim.list_extend(result, vim.split(left, ","))
+        table.insert(result, ",")
+        vim.list_extend(result, vim.split(right, ","))
+
+        table.sort(result)
+
+        return result
+      end
+
+      if string.find(value, ",^,,", 1, true) then
+        local comma_split = vim.split(value, ",^,,", true)
+        local left = comma_split[1]
+        local right = comma_split[2]
+
+        local result = {}
+        vim.list_extend(result, vim.split(left, ","))
+        table.insert(result, "^,")
+        vim.list_extend(result, vim.split(right, ","))
+
+        table.sort(result)
+
+        return result
+      end
+
       return vim.split(value, ",")
     end,
 

test/functional/api/vim_spec.lua

@@ -2003,6 +2003,7 @@ describe('API', function()
 
     it('should have information about window options', function()
       eq({
+        allows_duplicates = true,
         commalist = false;
         default = "";
         flaglist = false;
@@ -2020,6 +2021,7 @@ describe('API', function()
 
     it('should have information about buffer options', function()
       eq({
+        allows_duplicates = true,
         commalist = false,
         default = "",
         flaglist = false,
@@ -2041,6 +2043,7 @@ describe('API', function()
       eq(false, meths.get_option'showcmd')
 
       eq({
+        allows_duplicates = true,
         commalist = false,
         default = true,
         flaglist = false,

test/functional/lua/vim_spec.lua

@@ -1731,6 +1731,26 @@ describe('lua stdlib', function()
         ]]))
       end)
     end)
+
+    -- isfname=a,b,c,,,d,e,f
+    it('can handle isfname ,,,', function()
+      local result = exec_lua [[
+        vim.opt.isfname = "a,b,,,c"
+        return { vim.opt.isfname:get(), vim.api.nvim_get_option('isfname') }
+      ]]
+
+      eq({{",", "a", "b", "c"}, "a,b,,,c"}, result)
+    end)
+
+    -- isfname=a,b,c,^,,def
+    it('can handle isfname ,^,,', function()
+      local result = exec_lua [[
+        vim.opt.isfname = "a,b,^,,c"
+        return { vim.opt.isfname:get(), vim.api.nvim_get_option('isfname') }
+      ]]
+
+      eq({{"^,", "a", "b", "c"}, "a,b,^,,c"}, result)
+    end)
   end) -- vim.opt
 
   it('vim.cmd', function()