sql: fix COPY with hidden and inaccessible columns

Fixes #119524

Release note (bug fix): A bug has been fixed that caused panics when
executing `COPY` into a table with hidden columns and expression
indexes. The panic only occurred when the
`expect_and_ignore_not_visible_columns_in_copy` setting was enabled.
This bug has been present since
`expect_and_ignore_not_visible_columns_in_copy` was introduced in
v22.1.0.

Author: mgartner

pkg/sql/copy_from.go

@@ -343,9 +343,15 @@ func newCopyMachine(
 	// to have field data then we have to populate the expectedHiddenColumnIdxs
 	// field with the columns indexes we expect to be hidden.
 	if c.p.SessionData().ExpectAndIgnoreNotVisibleColumnsInCopy && len(n.Columns) == 0 {
+		numInaccessibleCols := 0
 		for i, col := range tableDesc.PublicColumns() {
 			if col.IsHidden() {
-				c.expectedHiddenColumnIdxs = append(c.expectedHiddenColumnIdxs, i)
+				// Offset the index by the number of preceding inaccessible
+				// columns, which are never expected in the input.
+				c.expectedHiddenColumnIdxs = append(c.expectedHiddenColumnIdxs, i-numInaccessibleCols)
+			}
+			if col.IsInaccessible() {
+				numInaccessibleCols++
 			}
 		}
 	}

pkg/sql/pgwire/testdata/pgtest/copy

@@ -199,6 +199,52 @@ ReadyForQuery
 {"Type":"CommandComplete","CommandTag":"SELECT 3"}
 {"Type":"ReadyForQuery","TxStatus":"I"}
 
+# Regression test for #119524. expect_and_ignore_not_visible_columns_in_copy
+# should behave correctly with inaccessible columns.
+send
+Query {"String": "CREATE TABLE t119524 (x INT PRIMARY KEY, y INT, INDEX ((x + y)))"}
+----
+
+until
+ReadyForQuery
+----
+{"Type":"CommandComplete","CommandTag":"CREATE TABLE"}
+{"Type":"ReadyForQuery","TxStatus":"I"}
+
+send
+Query {"String": "ALTER TABLE t119524 ADD COLUMN z INT NOT VISIBLE"}
+----
+
+until
+ReadyForQuery
+----
+{"Type":"CommandComplete","CommandTag":"ALTER TABLE"}
+{"Type":"ReadyForQuery","TxStatus":"I"}
+
+send crdb_only
+Query {"String": "COPY t119524 FROM STDIN"}
+CopyData {"Data": "1\t2\t3\n"}
+CopyDone
+----
+
+until crdb_only
+ReadyForQuery
+----
+{"Type":"CopyInResponse","ColumnFormatCodes":[0,0]}
+{"Type":"CommandComplete","CommandTag":"COPY 1"}
+{"Type":"ReadyForQuery","TxStatus":"I"}
+
+send crdb_only
+Query {"String": "SELECT *, z FROM t119524"}
+----
+
+until ignore=RowDescription crdb_only
+ReadyForQuery
+----
+{"Type":"DataRow","Values":[{"text":"1"},{"text":"2"},null]}
+{"Type":"CommandComplete","CommandTag":"SELECT 1"}
+{"Type":"ReadyForQuery","TxStatus":"I"}
+
 send crdb_only
 Query {"String": "SET expect_and_ignore_not_visible_columns_in_copy = false"}
 ----