From 2b24b0422002655f1a4b1bbf98b3ae91d2528c93 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Mon, 14 May 2018 23:22:59 +0300
Subject: [PATCH] Bug 27122803 - BACKPORT FIX FOR BUG 25899959 TO MYSQL-5.7

Merge a test case and a code change from MySQL 5.7.22.
There was no commit message, but a test case was included.
https://github.com/mysql/mysql-server/commit/d3ec326bcd8352fcd969dbfd54e5c604db9cd30b

There is no Bug 25899959 mentioned in the MySQL 8.0.11 history.
Based on the number, it should have been filed before August 2017.
Maybe it was initially fixed in a not-yet-public MySQL 9.0 branch?

The code change differs from MySQL 5.7, because the mbminmaxlen
were split in MariaDB in MDEV-7049.
---
 mysql-test/suite/gcol/r/innodb_virtual_index.result | 13 +++++++++++++
 mysql-test/suite/gcol/t/innodb_virtual_index.test   |  8 ++++++++
 storage/innobase/handler/handler0alter.cc           |  9 +++++++++
 3 files changed, 30 insertions(+)

diff --git a/mysql-test/suite/gcol/r/innodb_virtual_index.result b/mysql-test/suite/gcol/r/innodb_virtual_index.result
index b1f7976c6c0..a1faac8e1e8 100644
--- a/mysql-test/suite/gcol/r/innodb_virtual_index.result
+++ b/mysql-test/suite/gcol/r/innodb_virtual_index.result
@@ -198,3 +198,16 @@ VIRTUAL, ADD UNIQUE index idx (col1), algorithm=inplace;
 ERROR 0A000: ALGORITHM=INPLACE is not supported. Reason: INPLACE ADD or DROP of virtual columns cannot be combined with other ALTER TABLE actions. Try ALGORITHM=COPY
 DROP TABLE t1;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
+#
+# Bug 27122803 - BACKPORT FIX FOR BUG 25899959 TO MYSQL-5.7
+#
+CREATE TABLE t1 (col1 int(10)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+ALTER TABLE t1 ADD col2 char(21) AS (col1 * col1), ADD INDEX n (col2);
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `col1` int(10) DEFAULT NULL,
+  `col2` char(21) GENERATED ALWAYS AS (`col1` * `col1`) VIRTUAL,
+  KEY `n` (`col2`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
+DROP TABLE t1;
diff --git a/mysql-test/suite/gcol/t/innodb_virtual_index.test b/mysql-test/suite/gcol/t/innodb_virtual_index.test
index 432faeb65ae..6604a6d94f4 100644
--- a/mysql-test/suite/gcol/t/innodb_virtual_index.test
+++ b/mysql-test/suite/gcol/t/innodb_virtual_index.test
@@ -224,3 +224,11 @@ VIRTUAL, ADD UNIQUE index idx (col1), algorithm=inplace;
 
 DROP TABLE t1;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
+
+--echo #
+--echo # Bug 27122803 - BACKPORT FIX FOR BUG 25899959 TO MYSQL-5.7
+--echo #
+CREATE TABLE t1 (col1 int(10)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+ALTER TABLE t1 ADD col2 char(21) AS (col1 * col1), ADD INDEX n (col2);
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 2ae4f65efc5..f27f92dacb5 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -4385,6 +4385,15 @@ prepare_inplace_alter_table_dict(
 
 		if (ha_alter_info->handler_flags
 		    & Alter_inplace_info::ADD_INDEX) {
+			for (ulint i = 0; i < ctx->num_to_add_vcol; i++) {
+				/* Set mbminmax for newly added column */
+				dict_col_t& col = ctx->add_vcol[i].m_col;
+				ulint mbminlen, mbmaxlen;
+				dtype_get_mblen(col.mtype, col.prtype,
+						&mbminlen, &mbmaxlen);
+				col.mbminlen = mbminlen;
+				col.mbmaxlen = mbmaxlen;
+			}
 			add_v = static_cast<dict_add_v_col_t*>(
 				mem_heap_alloc(ctx->heap, sizeof *add_v));
 			add_v->n_v_col = ctx->num_to_add_vcol;