feat: generated and identity columns for mssql, sqlite, drizzle, typeorm, bun and gorm readers

- mssql: write computed columns (AS (expr) PERSISTED) and identity; read computed definition and identity
- sqlite: write GENERATED ALWAYS AS (expr) STORED; read generated columns via table_xinfo and parse the expression
- drizzle: generatedAlwaysAs / generated(Always|ByDefault)AsIdentity, read and write
- typeorm: asExpression/generatedType and identity decorators, read and write; decorator scan is now quote-aware
- bun, gorm readers: read generated and identity markers
- readmes updated

pkg/readers/bun/README.md

@@ -64,6 +64,8 @@ The reader recognizes the following Bun struct tags:
 - `autoincrement` - Auto-increment column
 - `default` - Default value
 - `unique` - Unique constraint
+- `generated` - Generated column marker (`Generated`; expression is not in the tag)
+- `identity` - Identity column marker (`Identity`, `ALWAYS`)
 - `rel` - Relationship definition
 
 ## Example Bun Model

pkg/readers/bun/generated_column_test.go

@@ -0,0 +1,48 @@
+package bun
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+func TestReader_GeneratedAndIdentityMarkers(t *testing.T) {
+	src := `package models
+
+import "github.com/uptrace/bun"
+
+type Person struct {
+	bun.BaseModel ` + "`bun:\"table:people,alias:p\"`" + `
+
+	ID       int64  ` + "`bun:\"id,pk,type:bigint,autoincrement,identity\"`" + `
+	Seq      int64  ` + "`bun:\"seq,type:bigint,scanonly,identity,notnull\"`" + `
+	FullName string ` + "`bun:\"full_name,type:text,scanonly,generated,nullzero\"`" + `
+	First    string ` + "`bun:\"first,type:text,nullzero\"`" + `
+}
+`
+	path := filepath.Join(t.TempDir(), "person.go")
+	if err := os.WriteFile(path, []byte(src), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := NewReader(&readers.ReaderOptions{FilePath: path}).ReadDatabase()
+	if err != nil {
+		t.Fatalf("ReadDatabase() error = %v", err)
+	}
+	cols := db.Schemas[0].Tables[0].Columns
+
+	if !cols["id"].Identity || cols["id"].IdentityGeneration != "ALWAYS" {
+		t.Errorf("id: identity = %v/%q, want true/ALWAYS", cols["id"].Identity, cols["id"].IdentityGeneration)
+	}
+	if !cols["seq"].Identity || cols["seq"].IdentityGeneration != "ALWAYS" {
+		t.Errorf("seq: identity = %v/%q, want true/ALWAYS", cols["seq"].Identity, cols["seq"].IdentityGeneration)
+	}
+	if !cols["full_name"].Generated {
+		t.Error("full_name should be generated")
+	}
+	if cols["first"].Generated || cols["first"].Identity {
+		t.Error("first must be an ordinary column")
+	}
+}

pkg/readers/bun/reader.go

@@ -659,6 +659,13 @@ func (r *Reader) parseColumn(fieldName string, fieldType ast.Expr, tag string, s
 			hasExplicitNullableMarker = true
 		case "autoincrement":
 			column.AutoIncrement = true
+		case "generated":
+			// GENERATED ... STORED marker written by the Bun writer; the expression is not in the tag
+			column.Generated = true
+		case "identity":
+			// GENERATED ALWAYS AS IDENTITY marker written by the Bun writer
+			column.Identity = true
+			column.IdentityGeneration = "ALWAYS"
 		case "default":
 			// Default value from Bun tag (e.g., default:gen_random_uuid())
 			column.Default = value