fix(ex.component): Fix extend method

.

.

lua/lualine/ex/component.lua

@@ -16,15 +16,19 @@ local log = require('plenary.log').new({ plugin = 'ex.component' })
 ---@field default_options table
 ---@field options ExComponentOptions
 
-local Ex = require('lualine.component'):extend()
+local LC = require('lualine.component')
+-- extends all methods from the `lualine.component`:
+local Ex = LC:extend()
 
+-- override the `extend` method to be able to receive the default options:
 function Ex:extend(default_options)
-    local cls = self.super.extend(self)
-    cls.default_options = ex.merge(vim.deepcopy(default_options or {}), {
+    local cls = LC.extend(self)
+    local parent_default_options = ex.merge(vim.deepcopy(self.default_options or {}), {
         disabled_color = { fg = 'grey' },
         disabled_icon_color = { fg = 'grey' },
         draw_empty = true,
     })
+    cls.default_options = vim.tbl_extend('force', parent_default_options, default_options or {})
     return cls
 end
 

lua/lualine/ex/init.lua

@@ -30,6 +30,8 @@ end
 
 ---@type fun(dest: table, source: table): table
 --- Puts all absent key-value pairs from the {source} to the {dest}.
+---@param dest table a table to which data should be added.
+---@param source table a table from which a data should be copied.
 ---@return table dest with added pairs.
 M.merge = function(dest, source, already_visited)
     vim.validate({ dest = { dest, 'table' }, source = { source, 'table' } })

tests/component_spec.lua

@@ -7,6 +7,52 @@ local same = assert.are.same
 local l = require('tests.ex.lualine')
 local t = require('tests.ex.busted') --:ignore_all_tests()
 
+describe('ex.component', function()
+    it('should have the same methods as lualine.component', function()
+        local Test = require('lualine.ex.component'):extend()
+        -- check only few:
+        assert(type(Test.update_status) == 'function')
+        assert(type(Test.draw) == 'function')
+    end)
+    it('child should have the same methods as ex.component', function()
+        local Test = require('lualine.ex.component'):extend()
+        -- check only few:
+        assert(type(Test.pre_init) == 'function')
+        assert(type(Test.post_init) == 'function')
+    end)
+    it('child`s default options should include parent`s', function()
+        -- given:
+        local Test = require('lualine.ex.component'):extend({ parent_opt = true })
+        -- when:
+        local Child = Test:extend({ child_opt = true })
+        -- then:
+        local clue = vim.inspect(Child.default_options)
+        assert(Child.default_options.parent_opt, clue)
+        assert(Child.default_options.child_opt, clue)
+    end)
+    it('child`s default options should override parent`s', function()
+        -- given:
+        local Test = require('lualine.ex.component'):extend({ opt = false })
+        -- when:
+        local Child = Test:extend({ opt = true })
+        -- then:
+        local clue = vim.inspect(Child.default_options)
+        assert(Child.default_options.opt, clue)
+    end)
+    it('instance of the child should have the same methods as a parent', function()
+        -- given:
+        local Test = require('lualine.ex.component'):extend()
+        function Test:test()
+            return true
+        end
+
+        local Child = Test:extend()
+        -- when:
+        local child = Child:new(u.opts({ icon = { align = 'right' } }))
+        -- then:
+        assert(type(child.test) == 'function')
+    end)
+end)
 describe('A child of the ex.component', function()
     it('should have the passed default options as a property', function()
         -- given:
@@ -46,6 +92,7 @@ describe('A child of the ex.component', function()
             function Ex:post_init()
                 passed_opts = self.options
             end
+
             -- when:
             Ex(init_opts)
             -- then:
@@ -67,6 +114,7 @@ describe('A child of the ex.component', function()
             function Child:update_status()
                 return ''
             end
+
             local cmp = Child(u.opts())
 
             -- when:
@@ -88,6 +136,7 @@ describe('A child of the ex.component', function()
             function Child:update_status()
                 return 'some_text'
             end
+
             local cmp = Child(u.opts())
 
             -- when:
@@ -103,9 +152,11 @@ describe('A child of the ex.component', function()
             function Child:update_status()
                 return 'some_text'
             end
+
             function Child:is_enabled()
                 return false
             end
+
             local cmp = Child(u.opts())
 
             -- when:
@@ -130,9 +181,11 @@ describe('A child of the ex.component', function()
             function Child:update_status()
                 return 'some_text'
             end
+
             function Child:is_enabled()
                 return is_enabled
             end
+
             local cmp = Child(u.opts())
 
             -- when: