From 732cd7fd5346885ae41293d7ebe44110188155d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Tue, 22 Sep 2020 11:13:51 +0300
Subject: [PATCH] MDEV-23705 Assertion 'table->data_dir_path || !space'

After DISCARD TABLESPACE, the tablespace of a table will no longer
exist, and dict_get_and_save_data_dir_path() would invoke
dict_get_first_path() to read an entry from SYS_DATAFILES.
For some reason, DISCARD TABLESPACE would not to remove the entry
from there.

dict_get_and_save_data_dir_path(): If the tablespace has been
discarded, do not bother trying to read the name.

Side note: The tables SYS_TABLESPACES and SYS_DATAFILES are
redundant and subject to removal in MDEV-22343.
---
 mysql-test/suite/innodb/r/truncate.result | 11 +++++++++++
 mysql-test/suite/innodb/t/truncate.test   | 10 ++++++++++
 storage/innobase/dict/dict0load.cc        |  3 ++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/mysql-test/suite/innodb/r/truncate.result b/mysql-test/suite/innodb/r/truncate.result
index 5e9fd60d4fe..571aa2da1c5 100644
--- a/mysql-test/suite/innodb/r/truncate.result
+++ b/mysql-test/suite/innodb/r/truncate.result
@@ -39,3 +39,14 @@ TRUNCATE t1;
 SELECT * FROM t1;
 a
 DROP TEMPORARY TABLE t1;
+#
+# MDEV-23705 Assertion 'table->data_dir_path || !space'
+#
+CREATE TABLE t(c INT) ENGINE=InnoDB;
+ALTER TABLE t DISCARD TABLESPACE;
+RENAME TABLE t TO u;
+TRUNCATE u;
+Warnings:
+Warning	1814	Tablespace has been discarded for table `u`
+TRUNCATE u;
+DROP TABLE u;
diff --git a/mysql-test/suite/innodb/t/truncate.test b/mysql-test/suite/innodb/t/truncate.test
index cd1d827e157..ca9ccb677e9 100644
--- a/mysql-test/suite/innodb/t/truncate.test
+++ b/mysql-test/suite/innodb/t/truncate.test
@@ -50,3 +50,13 @@ INSERT INTO t1 VALUES(1);
 TRUNCATE t1;
 SELECT * FROM t1;
 DROP TEMPORARY TABLE t1;
+
+--echo #
+--echo # MDEV-23705 Assertion 'table->data_dir_path || !space'
+--echo #
+CREATE TABLE t(c INT) ENGINE=InnoDB;
+ALTER TABLE t DISCARD TABLESPACE;
+RENAME TABLE t TO u;
+TRUNCATE u;
+TRUNCATE u;
+DROP TABLE u;
diff --git a/storage/innobase/dict/dict0load.cc b/storage/innobase/dict/dict0load.cc
index 4014d28c2fb..af14c6a4770 100644
--- a/storage/innobase/dict/dict0load.cc
+++ b/storage/innobase/dict/dict0load.cc
@@ -2739,7 +2739,8 @@ dict_get_and_save_data_dir_path(
 {
 	ut_ad(!dict_table_is_temporary(table));
 
-	if (!table->data_dir_path && table->space) {
+	if (!table->data_dir_path && table->space
+	    && !dict_table_is_discarded(table)) {
 		char*	path = fil_space_get_first_path(table->space);
 
 		if (!dict_mutex_own) {