MDEV-24491 db_name mismatch happens during virtual column computation

    Database name mismatch happens while opening the table for
virtual column computation. Because table_name_parse() returns
the length of database and table name before converting the
filename to table name. This issue is caused by
commit 8b0d4cff (MDEV-15855).
Fix should be that table_name_parse() should return the length of
database and table name after converting the filename to table name.

Reviewed-by: Marko Mäkelä

mysql-test/suite/gcol/r/innodb_virtual_fk.result

@@ -793,6 +793,9 @@ DROP TABLE t1;
 #
 # MDEV-24041 Generated column DELETE with FOREIGN KEY crash InnoDB
 #
+SET FOREIGN_KEY_CHECKS=1;
+CREATE DATABASE `a-b`;
+USE `a-b`;
 CREATE TABLE emails (
 id int,
 PRIMARY KEY (id)
@@ -802,6 +805,7 @@ id int,
 email_id int,
 date_sent char(4),
 generated_email_id int as (email_id),
+#generated_sent_date DATE GENERATED ALWAYS AS (date_sent),
 PRIMARY KEY (id),
 KEY mautic_generated_sent_date_email_id (generated_email_id),
 FOREIGN KEY (email_id) REFERENCES emails (id) ON DELETE SET NULL
@@ -818,3 +822,4 @@ DELETE FROM emails;
 DROP TABLE email_stats;
 DROP TABLE emails_metadata;
 DROP TABLE emails;
+DROP DATABASE `a-b`;

mysql-test/suite/gcol/t/innodb_virtual_fk.test

@@ -653,7 +653,9 @@ DROP TABLE t1;
 --echo #
 --echo # MDEV-24041 Generated column DELETE with FOREIGN KEY crash InnoDB
 --echo #
-
+SET FOREIGN_KEY_CHECKS=1;
+CREATE DATABASE `a-b`;
+USE `a-b`;
 CREATE TABLE emails (
   id int,
   PRIMARY KEY (id)
@@ -664,6 +666,7 @@ CREATE TABLE email_stats (
   email_id int,
   date_sent char(4),
   generated_email_id int as (email_id),
+  #generated_sent_date DATE GENERATED ALWAYS AS (date_sent),
   PRIMARY KEY (id),
   KEY mautic_generated_sent_date_email_id (generated_email_id),
   FOREIGN KEY (email_id) REFERENCES emails (id) ON DELETE SET NULL
@@ -686,3 +689,4 @@ DELETE FROM emails;
 DROP TABLE email_stats;
 DROP TABLE emails_metadata;
 DROP TABLE emails;
+DROP DATABASE `a-b`;

storage/innobase/handler/ha_innodb.cc

@@ -21543,7 +21543,7 @@ static bool table_name_parse(
 	memcpy(tbl_buf, tbl_name.m_name + dbnamelen + 1, tblnamelen);
 	tbl_buf[tblnamelen] = 0;
 
-	filename_to_tablename(db_buf, dbname, MAX_DATABASE_NAME_LEN + 1, true);
+	dbnamelen = filename_to_tablename(db_buf, dbname, MAX_DATABASE_NAME_LEN + 1, true);
 
 	if (tblnamelen > TEMP_FILE_PREFIX_LENGTH
 	    && !strncmp(tbl_buf, TEMP_FILE_PREFIX, TEMP_FILE_PREFIX_LENGTH)) {
@@ -21555,7 +21555,7 @@ static bool table_name_parse(
 		tblnamelen = is_part - tbl_buf;
 	}
 
-	filename_to_tablename(tbl_buf, tblname, MAX_TABLE_NAME_LEN + 1, true);
+	tblnamelen = filename_to_tablename(tbl_buf, tblname, MAX_TABLE_NAME_LEN + 1, true);
 	return true;
 }