[PATCH 03/10] ddl: synchronize func cache with actual data state

[Vladimir Davydov <vdavydov.dev@gmail.com>]

To implement transactional DDL, we must make sure that in-memory schema
is updated synchronously with system space updates, i.e. on_replace, not
on_commit.
---
 src/box/alter.cc            | 40 +++++++++++++++++++++++++++++++---------
 test/box/function1.result   | 34 ++++++++++++++++++++++++++++++++++
 test/box/function1.test.lua | 13 +++++++++++++
 3 files changed, 78 insertions(+), 9 deletions(-)

diff --git a/src/box/alter.cc b/src/box/alter.cc
index cc057298..062cf9f8 100644
--- a/src/box/alter.cc
+++ b/src/box/alter.cc
@@ -2587,14 +2587,31 @@ func_def_new_from_tuple(struct tuple *tuple)
 	return def;
 }
 
-/** Remove a function from function cache */
 static void
-func_cache_remove_func(struct trigger *trigger, void * /* event */)
+on_create_func_rollback(struct trigger *trigger, void * /* event */)
 {
-	struct func *old_func = (struct func *) trigger->data;
-	func_cache_delete(old_func->def->fid);
-	trigger_run_xc(&on_alter_func, old_func);
-	func_delete(old_func);
+	/* Remove the new function from the cache and delete it. */
+	struct func *func = (struct func *)trigger->data;
+	func_cache_delete(func->def->fid);
+	trigger_run_xc(&on_alter_func, func);
+	func_delete(func);
+}
+
+static void
+on_drop_func_commit(struct trigger *trigger, void * /* event */)
+{
+	/* Delete the old function. */
+	struct func *func = (struct func *)trigger->data;
+	func_delete(func);
+}
+
+static void
+on_drop_func_rollback(struct trigger *trigger, void * /* event */)
+{
+	/* Insert the old function back into the cache. */
+	struct func *func = (struct func *)trigger->data;
+	func_cache_insert(func);
+	trigger_run_xc(&on_alter_func, func);
 }
 
 /**
@@ -2619,15 +2636,15 @@ on_replace_dd_func(struct trigger * /* trigger */, void *event)
 		access_check_ddl(def->name, def->fid, def->uid, SC_FUNCTION,
 				 PRIV_C);
 		struct trigger *on_rollback =
-			txn_alter_trigger_new(func_cache_remove_func, NULL);
+			txn_alter_trigger_new(on_create_func_rollback, NULL);
 		struct func *func = func_new(def);
 		if (func == NULL)
 			diag_raise();
 		def_guard.is_active = false;
 		func_cache_insert(func);
 		on_rollback->data = func;
+		txn_on_rollback(txn, on_rollback);
 		trigger_run_xc(&on_alter_func, func);
-		txn_on_rollback(txn, on_rollback);
 	} else if (new_tuple == NULL) {         /* DELETE */
 		uint32_t uid;
 		func_def_get_ids_from_tuple(old_tuple, &fid, &uid);
@@ -2644,8 +2661,13 @@ on_replace_dd_func(struct trigger * /* trigger */, void *event)
 				  "function has grants");
 		}
 		struct trigger *on_commit =
-			txn_alter_trigger_new(func_cache_remove_func, old_func);
+			txn_alter_trigger_new(on_drop_func_commit, old_func);
+		struct trigger *on_rollback =
+			txn_alter_trigger_new(on_drop_func_rollback, old_func);
+		func_cache_delete(old_func->def->fid);
 		txn_on_commit(txn, on_commit);
+		txn_on_rollback(txn, on_rollback);
+		trigger_run_xc(&on_alter_func, old_func);
 	} else {                                /* UPDATE, REPLACE */
 		assert(new_tuple != NULL && old_tuple != NULL);
 		/**
diff --git a/test/box/function1.result b/test/box/function1.result
index 439e19e9..ec1ab5e6 100644
--- a/test/box/function1.result
+++ b/test/box/function1.result
@@ -530,3 +530,37 @@ test_run:cmd("clear filter")
 ---
 - true
 ...
+--
+-- Check that function cache is updated synchronously with _func changes.
+--
+box.begin() box.schema.func.create('test') f = box.func.test box.rollback()
+---
+...
+f ~= nil
+---
+- true
+...
+box.func.test == nil
+---
+- true
+...
+box.schema.func.create('test')
+---
+...
+f = box.func.test
+---
+...
+box.begin() box.space._func:delete{f.id} f = box.func.test box.rollback()
+---
+...
+f == nil
+---
+- true
+...
+box.func.test ~= nil
+---
+- true
+...
+box.func.test:drop()
+---
+...
diff --git a/test/box/function1.test.lua b/test/box/function1.test.lua
index 4ec9c04a..a891e192 100644
--- a/test/box/function1.test.lua
+++ b/test/box/function1.test.lua
@@ -185,3 +185,16 @@ box.schema.func.drop('secret_leak')
 box.schema.func.drop('secret')
 
 test_run:cmd("clear filter")
+
+--
+-- Check that function cache is updated synchronously with _func changes.
+--
+box.begin() box.schema.func.create('test') f = box.func.test box.rollback()
+f ~= nil
+box.func.test == nil
+box.schema.func.create('test')
+f = box.func.test
+box.begin() box.space._func:delete{f.id} f = box.func.test box.rollback()
+f == nil
+box.func.test ~= nil
+box.func.test:drop()
-- 
2.11.0