fix(dbml): resolve commented cross-file // Ref: lines

Commented refs are collected per file and resolved against the combined
model after all inputs are loaded (directory, --from-list, merge, jobs).
Matched refs become FKs and relationships; duplicates of existing FKs are
skipped; missing targets are skipped with a warning; column type
mismatches warn.

Also keep reused index names within a DBML table instead of overwriting,
give a second FK to the same table a distinct relationship name, and make
the pgsql writer match relationships to FKs by name first.

pkg/readers/dbml/reader.go

@@ -48,7 +48,22 @@ func (r *Reader) ReadDatabase() (*models.Database, error) {
 		return nil, fmt.Errorf("failed to read file: %w", err)
 	}
 
-	return r.parseDBML(string(content))
+	db, err := r.parseDBML(string(content))
+	if err != nil {
+		return nil, err
+	}
+	r.resolveCommentedRefs(db)
+	return db, nil
+}
+
+// resolveCommentedRefs resolves the commented refs whose tables are loaded.
+// Unmatched refs stay pending for a later pass over a combined model.
+func (r *Reader) resolveCommentedRefs(db *models.Database) {
+	for _, w := range ResolveCommentedRefs(db, false) {
+		if r.options.Progress != nil {
+			r.options.Progress("warning: " + w)
+		}
+	}
 }
 
 // ReadSchema reads and parses DBML input, returning a Schema model
@@ -125,6 +140,7 @@ func (r *Reader) readDirectoryDBML(dirPath string) (*models.Database, error) {
 		}
 	}
 
+	r.resolveCommentedRefs(db)
 	return db, nil
 }
 
@@ -440,6 +456,10 @@ func mergeDatabase(baseDB, fileDB *models.Database) {
 	// Merge domains
 	baseDB.Domains = append(baseDB.Domains, fileDB.Domains...)
 
+	for _, ref := range PendingCommentedRefs(fileDB) {
+		addPendingCommentedRef(baseDB, ref)
+	}
+
 	// Use first non-empty description
 	if baseDB.Description == "" && fileDB.Description != "" {
 		baseDB.Description = fileDB.Description
@@ -493,8 +513,12 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 			continue
 		}
 
-		// Skip empty lines and comments
+		// Skip empty lines and comments. A commented `// Ref:` is kept as a
+		// pending cross-file ref, resolved once every file is loaded.
 		if line == "" || strings.HasPrefix(line, "//") {
+			if ref, ok := commentedRef(line); ok {
+				addPendingCommentedRef(db, ref)
+			}
 			continue
 		}
 
@@ -581,7 +605,13 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 
 			index := r.parseIndex(line, currentTable.Name, currentSchema)
 			if index != nil {
-				currentTable.Indexes[index.Name] = index
+				// Keep a reused name under a unique map key so the duplicate is
+				// not silently dropped; the inspector reports it.
+				key := index.Name
+				for n := 2; currentTable.Indexes[key] != nil; n++ {
+					key = fmt.Sprintf("%s#%d", index.Name, n)
+				}
+				currentTable.Indexes[key] = index
 				lastIndex = index
 			}
 			continue
@@ -659,20 +689,12 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 	// for DBML refs so diffing equivalent schemas compares the same model.
 	for _, schema := range schemaMap {
 		for _, table := range schema.Tables {
-			for _, constraint := range table.Constraints {
+			for _, name := range sortedConstraintNames(table.Constraints) {
+				constraint := table.Constraints[name]
 				if constraint.Type != models.ForeignKeyConstraint {
 					continue
 				}
-				name := fmt.Sprintf("%s_to_%s", table.Name, constraint.ReferencedTable)
-				relationship := models.InitRelationship(name, models.OneToMany)
-				relationship.FromTable = table.Name
-				relationship.FromSchema = table.Schema
-				relationship.FromColumns = append([]string(nil), constraint.Columns...)
-				relationship.ToTable = constraint.ReferencedTable
-				relationship.ToSchema = constraint.ReferencedSchema
-				relationship.ToColumns = append([]string(nil), constraint.ReferencedColumns...)
-				relationship.ForeignKey = constraint.Name
-				table.Relationships[name] = relationship
+				addFKRelationship(table, constraint)
 			}
 		}
 	}
@@ -685,6 +707,39 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 	return db, nil
 }
 
+// sortedConstraintNames returns constraint keys in sorted order so derived
+// relationship names do not depend on map iteration order.
+func sortedConstraintNames(constraints map[string]*models.Constraint) []string {
+	names := make([]string, 0, len(constraints))
+	for name := range constraints {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+// addFKRelationship derives the relationship for a foreign key, matching how
+// the PostgreSQL reader models FKs.
+func addFKRelationship(table *models.Table, constraint *models.Constraint) {
+	name := fmt.Sprintf("%s_to_%s", table.Name, constraint.ReferencedTable)
+	if existing, taken := table.Relationships[name]; taken && existing.ForeignKey != constraint.Name {
+		// A second FK to the same table must not overwrite the first.
+		name = fmt.Sprintf("%s_%s", name, strings.Join(constraint.Columns, "_"))
+	}
+	relationship := models.InitRelationship(name, models.OneToMany)
+	relationship.FromTable = table.Name
+	relationship.FromSchema = table.Schema
+	relationship.FromColumns = append([]string(nil), constraint.Columns...)
+	relationship.ToTable = constraint.ReferencedTable
+	relationship.ToSchema = constraint.ReferencedSchema
+	relationship.ToColumns = append([]string(nil), constraint.ReferencedColumns...)
+	relationship.ForeignKey = constraint.Name
+	if table.Relationships == nil {
+		table.Relationships = make(map[string]*models.Relationship)
+	}
+	table.Relationships[name] = relationship
+}
+
 // setTableNote preserves multiple table notes. The first maps to Description
 // and the second to Comment, matching the model fields used by code writers.
 func setTableNote(table *models.Table, note string) {