MDEV-18090 Assertion failures due to virtual columns after upgrading to 10.2

MariaDB before MDEV-5800 in version 10.2.2 did not support
indexed virtual columns. Non-persistent virtual columns were
hidden from storage engines. Only starting with MDEV-5800, InnoDB
would create internal metadata on virtual columns.

Similar to what was done in MDEV-18084 and MDEV-18960, we adjust two more
code paths for the old tables.

ha_innobase::build_template(): Do not invoke
dict_index_contains_col_or_prefix() for virtual columns if InnoDB
does not store the metadata.

innobase_build_col_map(): Relax an assertion about the number of columns.

ha_innobase::omits_virtual_cols(): Renamed from omits_virtual_cols().

3 files changed, 19 insertions, 14 deletions

diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 9366b2db30b..b448f71d6d0 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -275,12 +275,6 @@ void set_my_errno(int err)
 	errno = err;
 }
 
-static uint omits_virtual_cols(const TABLE_SHARE &share)
-{
-	return share.frm_version < FRM_VER_EXPRESSSIONS &&
-	       share.virtual_fields;
-}
-
 /** Checks whether the file name belongs to a partition of a table.
 @param[in]	file_name	file name
 @return pointer to the end of the table name part of the file name, or NULL */
@@ -7475,7 +7469,8 @@ build_template_needs_field(
 {
 	const Field*	field	= table->field[i];
 
-	if (!field->stored_in_db() && omits_virtual_cols(*table->s)) {
+	if (!field->stored_in_db()
+	    && ha_innobase::omits_virtual_cols(*table->s)) {
 		return NULL;
 	}
 
@@ -7632,7 +7627,7 @@ build_template_field(
 						&templ->rec_prefix_field_no);
 		}
 	} else {
-		ut_ad(!omits_virtual_cols(*table->s));
+		DBUG_ASSERT(!ha_innobase::omits_virtual_cols(*table->s));
 		col = &dict_table_get_nth_v_col(index->table, v_no)->m_col;
 		templ->clust_rec_field_no = v_no;
 		templ->rec_prefix_field_no = ULINT_UNDEFINED;
@@ -8019,7 +8014,8 @@ no_icp:
 					contain = dict_index_contains_col_or_prefix(
 						index, i - num_v,
 						false);
-				} else if (dict_index_is_clust(index)) {
+				} else if (skip_virtual
+					   || dict_index_is_clust(index)) {
 					num_v++;
 					continue;
 				} else {
@@ -8521,7 +8517,7 @@ calc_row_difference(
 	trx_t* const	trx = prebuilt->trx;
 	doc_id_t	doc_id = FTS_NULL_DOC_ID;
 	ulint		num_v = 0;
-	const bool 	skip_virtual = omits_virtual_cols(*table->s);
+	const bool skip_virtual = ha_innobase::omits_virtual_cols(*table->s);
 
 	ut_ad(!srv_read_only_mode);
 
@@ -11063,7 +11059,7 @@ create_table_info_t::create_table_def()
 
 	/* Find out the number of virtual columns. */
 	ulint num_v = 0;
-	const bool omit_virtual = omits_virtual_cols(*m_form->s);
+	const bool omit_virtual = ha_innobase::omits_virtual_cols(*m_form->s);
 	const ulint n_cols = omit_virtual
 		? m_form->s->stored_fields : m_form->s->fields;
 
diff --git a/storage/innobase/handler/ha_innodb.h b/storage/innobase/handler/ha_innodb.h
index 76a9b08c4c6..9311056bde5 100644
--- a/storage/innobase/handler/ha_innodb.h
+++ b/storage/innobase/handler/ha_innodb.h
@@ -22,6 +22,8 @@ this program; if not, write to the Free Software Foundation, Inc.,
 # include "../../../wsrep/wsrep_api.h"
 #endif /* WITH_WSREP */
 
+#include "table.h"
+
 /* The InnoDB handler: the interface between MySQL and InnoDB. */
 
 /** "GEN_CLUST_INDEX" is the name reserved for InnoDB default
@@ -412,8 +414,15 @@ public:
 	Item* idx_cond_push(uint keyno, Item* idx_cond);
 	/* @} */
 
-protected:
+	/** Check if InnoDB is not storing virtual column metadata for a table.
+	@param	s	table definition (based on .frm file)
+	@return	whether InnoDB will omit virtual column metadata */
+	static bool omits_virtual_cols(const TABLE_SHARE& s)
+	{
+		return s.frm_version<FRM_VER_EXPRESSSIONS && s.virtual_fields;
+	}
 
+protected:
 	/**
 	MySQL calls this method at the end of each statement. This method
 	exists for readability only, called from reset(). The name reset()
@@ -430,7 +439,6 @@ protected:
 	@see build_template() */
 	void reset_template();
 
-protected:
 	inline void update_thd(THD* thd);
 	void update_thd();
 
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 095fad367b3..3faf62479ff 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -3036,7 +3036,8 @@ innobase_build_col_map(
 		    >= altered_table->s->fields + DATA_N_SYS_COLS);
 	DBUG_ASSERT(dict_table_get_n_cols(old_table)
 		    + dict_table_get_n_v_cols(old_table)
-		    >= table->s->fields + DATA_N_SYS_COLS);
+		    >= table->s->fields + DATA_N_SYS_COLS
+		    || ha_innobase::omits_virtual_cols(*table->s));
 	DBUG_ASSERT(!!add_cols == !!(ha_alter_info->handler_flags
 				     & Alter_inplace_info::ADD_COLUMN));
 	DBUG_ASSERT(!add_cols || dtuple_get_n_fields(add_cols)