Add cmp.config.disable for opt-out default setting

lua/cmp/init.lua

@@ -3,6 +3,7 @@ local source = require('cmp.source')
 local config = require('cmp.config')
 local autocmd = require('cmp.utils.autocmd')
 local keymap = require('cmp.utils.keymap')
+local misc = require('cmp.utils.misc')
 
 local cmp = {}
 
@@ -17,6 +18,7 @@ cmp.vim = require('cmp.types.vim')
 
 ---Export default config presets.
 cmp.config = {}
+cmp.config.disable = misc.none
 cmp.config.compare = require('cmp.config.compare')
 cmp.config.sources = require('cmp.config.sources')
 

lua/cmp/utils/misc.lua

@@ -29,6 +29,9 @@ misc.concat = function(list1, list2)
   return new_list
 end
 
+---The symbol to remove key in misc.merge.
+misc.none = vim.NIL
+
 ---Merge two tables recursively
 ---@generic T
 ---@param v1 T
@@ -49,6 +52,9 @@ misc.merge = function(v1, v2)
     end
     return new_tbl
   end
+  if v1 == misc.none then
+    return nil
+  end
   if v1 == nil then
     return v2
   end

lua/cmp/utils/misc_spec.lua

@@ -15,6 +15,7 @@ describe('misc', function()
       },
     })
     assert.are.equal(merged.a.b, 1)
+
     merged = misc.merge({
       a = false,
     }, {
@@ -23,5 +24,14 @@ describe('misc', function()
       },
     })
     assert.are.equal(merged.a, false)
+
+    merged = misc.merge({
+      a = misc.none,
+    }, {
+      a = {
+        b = 1,
+      },
+    })
+    assert.are.equal(merged.a, nil)
   end)
 end)