feat(schema) allow partial update of record fields

Author: hishamhm

kong/db/schema/init.lua

@@ -468,6 +468,24 @@ Schema.entity_checkers = {
 }
 
 
+local function memoize(fn)
+  local cache = setmetatable({}, { __mode = "k" })
+  return function(k)
+    if cache[k] then
+      return cache[k]
+    end
+    local v = fn(k)
+    cache[k] = v
+    return v
+  end
+end
+
+
+local get_field_schema = memoize(function(field)
+  return Schema.new(field)
+end)
+
+
 -- Forward declaration
 local validate_fields
 
@@ -568,7 +586,7 @@ function Schema:validate_field(field, value)
       return nil, validation_errors.SCHEMA_MISSING_ATTRIBUTE:format("fields")
     end
 
-    local field_schema = Schema.new(field)
+    local field_schema = get_field_schema(field)
     -- TODO return nested table or string?
     local copy = field_schema:process_auto_fields(value, "insert")
     local ok, err = field_schema:validate(copy)
@@ -686,7 +704,7 @@ end
 -- @param entity The entity object where key `k` is missing.
 local function handle_missing_field(k, field, entity)
   if field.default ~= nil then
-    entity[k] = field.default
+    entity[k] = tablex.deepcopy(field.default)
     return
   end
 
@@ -1028,7 +1046,9 @@ end
 
 --- Given a table, update its fields whose schema
 -- definition declares them as `auto = true`,
--- based on its CRUD operation context.
+-- based on its CRUD operation context, and set
+-- defaults for missing values when the CRUD context
+-- is "insert".
 -- This function encapsulates various "smart behaviors"
 -- for value creation and update.
 -- @param input The table containing data to be processed.
@@ -1064,6 +1084,11 @@ function Schema:process_auto_fields(input, context)
         output[key] = make_array(field_value)
       elseif field_type == "set" then
         output[key] = make_set(field_value)
+      elseif field_type == "record" then
+        if field_value ~= null then
+          local field_schema = get_field_schema(field)
+          output[key] = field_schema:process_auto_fields(field_value, context)
+        end
       end
 
     elseif context ~= "update" then

spec/01-unit/000-new-dao/01-schema/01-schema_spec.lua

@@ -1525,6 +1525,24 @@ describe("schema", function()
                     { f = { type = "number" }, },
                   },
                   default = { f = 123 } }, },
+          { nested_record = {
+              type = "record",
+              default = {
+                r = {
+                  a = "nr",
+                  b = 123,
+                }
+              },
+              fields = {
+                { r = {
+                    type = "record",
+                    fields = {
+                      { a = { type = "string" } },
+                      { b = { type = "number" } }
+                    }
+                } }
+              }
+          } }
         }
       })
       check_all_types_covered(Test.fields)
@@ -1537,6 +1555,7 @@ describe("schema", function()
       assert.same("foo",                data.f)
       assert.same({ foo = 1, bar = 2 }, data.g)
       assert.same({ f = 123 },          data.h)
+      assert.same({ r = { a = "nr", b = 123, }}, data.nested_record)
     end)
 
     it("honors 'false' as a default", function()