Revert "MDEV-26220 Server crashes with indexed by prefix virtual column"

This reverts commit 9b8e207ce03b2ab7a766348738055be9520561bd.

4 files changed, 48 insertions, 99 deletions

diff --git a/mysql-test/suite/gcol/inc/gcol_partition.inc b/mysql-test/suite/gcol/inc/gcol_partition.inc
index 50a743c0153..4e4af4f0023 100644
--- a/mysql-test/suite/gcol/inc/gcol_partition.inc
+++ b/mysql-test/suite/gcol/inc/gcol_partition.inc
@@ -169,15 +169,3 @@ CREATE TABLE t1 (
 INSERT INTO t1 () VALUES (),();
 UPDATE t1 SET a = 0 WHERE b IS NULL ORDER BY pk;
 DROP TABLE t1;
-
---echo #
---echo # MDEV-26220 Server crashes with indexed by prefix virtual column
---echo #
-
-CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b CHAR(20), c CHAR(20) AS (b),
-                 KEY (c(10),a)) PARTITION BY HASH(pk);
-INSERT INTO t1 (pk,a,b) VALUES (1,10,'foo'),(2,11,'baz');
-SELECT a FROM t1;
-
-# Cleanup
-DROP TABLE t1;
diff --git a/mysql-test/suite/gcol/r/gcol_partition_innodb.result b/mysql-test/suite/gcol/r/gcol_partition_innodb.result
index e61c0a26417..d3f211c9b9a 100644
--- a/mysql-test/suite/gcol/r/gcol_partition_innodb.result
+++ b/mysql-test/suite/gcol/r/gcol_partition_innodb.result
@@ -104,17 +104,6 @@ INSERT INTO t1 () VALUES (),();
 UPDATE t1 SET a = 0 WHERE b IS NULL ORDER BY pk;
 DROP TABLE t1;
 #
-# MDEV-26220 Server crashes with indexed by prefix virtual column
-#
-CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b CHAR(20), c CHAR(20) AS (b),
-KEY (c(10),a)) PARTITION BY HASH(pk);
-INSERT INTO t1 (pk,a,b) VALUES (1,10,'foo'),(2,11,'baz');
-SELECT a FROM t1;
-a
-11
-10
-DROP TABLE t1;
-#
 # MDEV-16980 Wrongly set tablename len while opening the
 #                table for purge thread
 #
diff --git a/mysql-test/suite/gcol/r/gcol_partition_myisam.result b/mysql-test/suite/gcol/r/gcol_partition_myisam.result
index e54b0ad83c6..75e216f903b 100644
--- a/mysql-test/suite/gcol/r/gcol_partition_myisam.result
+++ b/mysql-test/suite/gcol/r/gcol_partition_myisam.result
@@ -101,17 +101,6 @@ KEY (b,d)
 INSERT INTO t1 () VALUES (),();
 UPDATE t1 SET a = 0 WHERE b IS NULL ORDER BY pk;
 DROP TABLE t1;
-#
-# MDEV-26220 Server crashes with indexed by prefix virtual column
-#
-CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b CHAR(20), c CHAR(20) AS (b),
-KEY (c(10),a)) PARTITION BY HASH(pk);
-INSERT INTO t1 (pk,a,b) VALUES (1,10,'foo'),(2,11,'baz');
-SELECT a FROM t1;
-a
-11
-10
-DROP TABLE t1;
 DROP VIEW  IF EXISTS v1,v2;
 DROP TABLE IF EXISTS t1,t2,t3;
 DROP PROCEDURE IF EXISTS p1;
diff --git a/sql/table.cc b/sql/table.cc
index ab2429f469f..b7cf1274400 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -3034,66 +3034,6 @@ static bool check_vcol_forward_refs(Field *field, Virtual_column_info *vcol)
   return res;
 }
 
-/**
- Copy keys from share to a table, so that fields in key_parts would match
- fields in a table.
-
- Also if key_part uses a field prefix, clone a field and make its length match
- that prefix.
-
- @retval true if success
- @retval false if memory allocation fails
- */
-static bool initialize_keys(TABLE_SHARE *share, TABLE *outparam)
-{
-  if (share->key_parts == 0)
-    return true;
-  uint n_length= share->keys * sizeof(KEY)
-                 + share->ext_key_parts * sizeof(KEY_PART_INFO);
-
-  KEY *key_info= (KEY*) alloc_root(&outparam->mem_root, n_length);
-  if (!key_info)
-    return false;
-
-  outparam->key_info= key_info;
-
-  KEY *key_info_end= key_info + share->keys;
-  KEY_PART_INFO *key_part= reinterpret_cast<KEY_PART_INFO*>(key_info_end);
-
-  memcpy(key_info, share->key_info, sizeof(*key_info) * share->keys);
-  memcpy(key_part, share->key_info[0].key_part, (sizeof(*key_part) *
-                                                 share->ext_key_parts));
-
-  for ( ; key_info < key_info_end; key_info++)
-  {
-    key_info->table= outparam;
-    key_info->key_part= key_part;
-
-    KEY_PART_INFO *key_part_end= key_part + (share->use_ext_keys
-                                            ? key_info->ext_key_parts
-                                            : key_info->user_defined_key_parts);
-    for ( ; key_part < key_part_end; key_part++)
-    {
-      Field *field= key_part->field= outparam->field[key_part->fieldnr - 1];
-
-      if (field->key_length() != key_part->length &&
-          !(field->flags & BLOB_FLAG))
-      {
-        /*
-          We are using only a prefix of the column as a key:
-          Create a new field for the key part that matches the index
-        */
-        field= key_part->field=field->make_new_field(&outparam->mem_root,
-                                                     outparam, 0);
-        field->field_length= key_part->length;
-      }
-    }
-    if (!share->use_ext_keys)
-      key_part+= key_info->ext_key_parts - key_info->user_defined_key_parts;
-  }
-  return true;
-}
-
 /*
   Open a table based on a TABLE_SHARE
 
@@ -3133,7 +3073,6 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
   Field **field_ptr;
   uint8 save_context_analysis_only= thd->lex->context_analysis_only;
   TABLE_SHARE::enum_v_keys check_set_initialized= share->check_set_initialized;
-  bool success;
   DBUG_ENTER("open_table_from_share");
   DBUG_PRINT("enter",("name: '%s.%s'  form: %p", share->db.str,
                       share->table_name.str, outparam));
@@ -3243,6 +3182,54 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
     outparam->found_next_number_field=
       outparam->field[(uint) (share->found_next_number_field - share->field)];
 
+  /* Fix key->name and key_part->field */
+  if (share->key_parts)
+  {
+    KEY	*key_info, *key_info_end;
+    KEY_PART_INFO *key_part;
+    uint n_length;
+    n_length= share->keys*sizeof(KEY) + share->ext_key_parts*sizeof(KEY_PART_INFO);
+    if (!(key_info= (KEY*) alloc_root(&outparam->mem_root, n_length)))
+      goto err;
+    outparam->key_info= key_info;
+    key_part= (reinterpret_cast<KEY_PART_INFO*>(key_info+share->keys));
+
+    memcpy(key_info, share->key_info, sizeof(*key_info)*share->keys);
+    memcpy(key_part, share->key_info[0].key_part, (sizeof(*key_part) *
+                                                   share->ext_key_parts));
+
+    for (key_info_end= key_info + share->keys ;
+         key_info < key_info_end ;
+         key_info++)
+    {
+      KEY_PART_INFO *key_part_end;
+
+      key_info->table= outparam;
+      key_info->key_part= key_part;
+
+      key_part_end= key_part + (share->use_ext_keys ? key_info->ext_key_parts :
+			                              key_info->user_defined_key_parts) ;
+      for ( ; key_part < key_part_end; key_part++)
+      {
+        Field *field= key_part->field= outparam->field[key_part->fieldnr - 1];
+
+        if (field->key_length() != key_part->length &&
+            !(field->flags & BLOB_FLAG))
+        {
+          /*
+            We are using only a prefix of the column as a key:
+            Create a new field for the key part that matches the index
+          */
+          field= key_part->field=field->make_new_field(&outparam->mem_root,
+                                                       outparam, 0);
+          field->field_length= key_part->length;
+        }
+      }
+      if (!share->use_ext_keys)
+	key_part+= key_info->ext_key_parts - key_info->user_defined_key_parts;
+    }
+  }
+
   /*
     Process virtual and default columns, if any.
   */
@@ -3299,10 +3286,6 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
     switch_defaults_to_nullable_trigger_fields(outparam);
   }
 
-  success= initialize_keys(share, outparam);
-  if (!success)
-    goto err;
-
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   if (share->partition_info_str_len && outparam->file)
   {