duplicate indexes on duplicated columns

examples/.ledger

@@ -46,3 +46,4 @@
 46_alter_column_drop_default.json
 47_add_table_foreign_key_constraint.json
 48_drop_tickets_check.json
+49_set_not_null_on_indexed_column.json

examples/49_set_not_null_on_indexed_column.json

@@ -0,0 +1,14 @@
+{
+  "name": "49_unset_not_null_on_indexed_column",
+  "operations": [
+    {
+      "alter_column": {
+        "table": "fruits",
+        "column": "name",
+        "nullable": true,
+        "up": "SELECT CASE WHEN name IS NULL THEN 'unknown fruit' ELSE name END",
+        "down": "name"
+      }
+    }
+  ]
+}

pkg/migrations/duplicate.go

@@ -147,6 +147,13 @@ func (d *Duplicator) Duplicate(ctx context.Context) error {
 		}
 	}
 
+	// Generate SQL to duplicate any indexes on the columns.
+	for _, sql := range d.stmtBuilder.duplicateIndexes(d.withoutConstraint, colNames...) {
+		if _, err := d.conn.ExecContext(ctx, sql); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
@@ -204,6 +211,44 @@ func (d *duplicatorStmtBuilder) duplicateForeignKeyConstraints(withoutConstraint
 	return stmts
 }
 
+func (d *duplicatorStmtBuilder) duplicateIndexes(withoutConstraint []string, colNames ...string) []string {
+	stmts := make([]string, 0, len(d.table.Indexes))
+	for _, idx := range d.table.Indexes {
+		if slices.Contains(withoutConstraint, idx.Name) {
+			continue
+		}
+		if _, ok := d.table.UniqueConstraints[idx.Name]; ok && idx.Unique {
+			// unique constraints are duplicated as unique indexes
+			continue
+		}
+
+		if duplicatedMember, columns := d.allConstraintColumns(idx.Columns, colNames...); duplicatedMember {
+			stmtFmt := "CREATE INDEX %s ON %s"
+			if idx.Unique {
+				stmtFmt = "CREATE UNIQUE INDEX %s ON %s"
+			}
+			stmt := fmt.Sprintf(stmtFmt, pq.QuoteIdentifier(DuplicationName(idx.Name)), pq.QuoteIdentifier(d.table.Name))
+			if idx.Method != "" {
+				stmt += fmt.Sprintf(" USING %s", string(idx.Method))
+			}
+
+			stmt += fmt.Sprintf(" (%s)", strings.Join(quoteColumnNames(columns), ", "))
+
+			if idx.StorageParameters != "" {
+				stmt += fmt.Sprintf(" WITH (%s)", idx.StorageParameters)
+			}
+
+			if idx.Predicate != nil {
+				pred := strings.Replace(*idx.Predicate, strings.Join(idx.Columns, ", "), strings.Join(quoteColumnNames(columns), ", "), 1)
+				stmt += fmt.Sprintf(" WHERE %s", pred)
+			}
+
+			stmts = append(stmts, stmt)
+		}
+	}
+	return stmts
+}
+
 // duplicatedConstraintColumns returns a new slice of constraint columns with
 // the columns that are duplicated replaced with temporary names.
 func (d *duplicatorStmtBuilder) duplicatedConstraintColumns(constraintColumns []string, duplicatedColumns ...string) []string {

pkg/migrations/rename.go

@@ -120,42 +120,42 @@ func RenameDuplicatedColumn(ctx context.Context, conn db.DB, table *schema.Table
 		}
 	}
 
-	// Rename any `UNIQUE` indexes on the duplicated column and use them to
+	// Rename any indexes on the duplicated column and use unique indexes to
 	// create `UNIQUE` constraints.
-	for _, ui := range table.Indexes {
-		if !IsDuplicatedName(ui.Name) {
-			continue
-		}
-		if !ui.Unique {
+	for _, idx := range table.Indexes {
+		if !IsDuplicatedName(idx.Name) {
 			continue
 		}
 
-		if slices.Contains(ui.Columns, TemporaryName(column.Name)) {
-			// Rename the unique index to its original name
+		if slices.Contains(idx.Columns, TemporaryName(column.Name)) {
+			// Rename the index to its original name
 			renameIndexSQL := fmt.Sprintf(cRenameIndexSQL,
-				pq.QuoteIdentifier(ui.Name),
-				pq.QuoteIdentifier(StripDuplicationPrefix(ui.Name)),
+				pq.QuoteIdentifier(idx.Name),
+				pq.QuoteIdentifier(StripDuplicationPrefix(idx.Name)),
 			)
 
 			_, err = conn.ExecContext(ctx, renameIndexSQL)
 			if err != nil {
-				return fmt.Errorf("failed to rename unique index %q: %w", ui.Name, err)
+				return fmt.Errorf("failed to rename index %q: %w", idx.Name, err)
 			}
+		}
 
+		if idx.Unique {
 			// Create a unique constraint using the unique index
 			createUniqueConstraintSQL := fmt.Sprintf(cCreateUniqueConstraintSQL,
 				pq.QuoteIdentifier(table.Name),
-				pq.QuoteIdentifier(StripDuplicationPrefix(ui.Name)),
-				pq.QuoteIdentifier(StripDuplicationPrefix(ui.Name)),
+				pq.QuoteIdentifier(StripDuplicationPrefix(idx.Name)),
+				pq.QuoteIdentifier(StripDuplicationPrefix(idx.Name)),
 			)
 
 			_, err = conn.ExecContext(ctx, createUniqueConstraintSQL)
 			if err != nil {
-				return fmt.Errorf("failed to create unique constraint from index %q: %w", ui.Name, err)
+				return fmt.Errorf("failed to create unique constraint from index %q: %w", idx.Name, err)
 			}
-			// Index no longer exists, remove it from the table
-			delete(table.Indexes, ui.Name)
 		}
+
+		// Index no longer exists, remove it from the table
+		delete(table.Indexes, idx.Name)
 	}
 
 	return nil

pkg/schema/schema.go

@@ -96,6 +96,9 @@ type Index struct {
 	// Method is the method for the index
 	Method string `json:"method,omitempty"`
 
+	// StorageParameters is the storage parameters for the index
+	StorageParameters string `json:"storageParameters,omitempty"`
+
 	// Definition is statement to construct the index
 	Definition string `json:"definition"`
 }