fix: preserve MySQL schema fidelity

pkg/writers/mysql/live_diagnostics_test.go

@@ -0,0 +1,140 @@
+package mysql_test
+
+import (
+	"database/sql"
+	"fmt"
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	driver "github.com/go-sql-driver/mysql"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+	rmysql "git.warky.dev/wdevs/relspecgo/pkg/readers/mysql"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+	wmysql "git.warky.dev/wdevs/relspecgo/pkg/writers/mysql"
+)
+
+func TestLiveUnsupportedObjectsDiagnosed(t *testing.T) {
+	conn := os.Getenv("RELSPEC_TEST_MYSQL_CONN")
+	if conn == "" {
+		t.Skip("RELSPEC_TEST_MYSQL_CONN is not set")
+	}
+	db, err := sql.Open("mysql", conn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { db.Close() })
+	prefix := fmt.Sprintf("unsupported_%d", time.Now().UnixNano())
+	table, view, trigger := prefix+"_table", prefix+"_view", prefix+"_trigger"
+	t.Cleanup(func() {
+		for _, stmt := range []string{"DROP VIEW IF EXISTS " + view, "DROP TRIGGER IF EXISTS " + trigger, "DROP TABLE IF EXISTS " + table} {
+			if _, err := db.Exec(stmt); err != nil {
+				t.Error(err)
+			}
+		}
+	})
+	for _, stmt := range []string{
+		"CREATE TABLE " + table + " (id INT PRIMARY KEY) PARTITION BY HASH(id) PARTITIONS 2",
+		"CREATE VIEW " + view + " AS SELECT id FROM " + table,
+		"CREATE TRIGGER " + trigger + " BEFORE INSERT ON " + table + " FOR EACH ROW SET NEW.id = NEW.id + 1",
+	} {
+		if _, err := db.Exec(stmt); err != nil {
+			t.Fatalf("%s: %v", stmt, err)
+		}
+	}
+	model, err := rmysql.NewReader(&readers.ReaderOptions{ConnectionString: conn}).ReadDatabase()
+	if err != nil {
+		t.Fatal(err)
+	}
+	path := filepath.Join(t.TempDir(), "schema.sql")
+	if err := os.WriteFile(path, []byte("original"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	err = wmysql.NewWriter(&writers.WriterOptions{StrictConversion: true, OutputPath: path}).WriteDatabase(model)
+	for _, want := range []string{"partitioned table", view, trigger} {
+		if err == nil || !strings.Contains(err.Error(), want) {
+			t.Errorf("missing diagnostic %s: %v", want, err)
+		}
+	}
+	bytes, readErr := os.ReadFile(path)
+	if readErr != nil || string(bytes) != "original" {
+		t.Fatalf("strict failure touched file: %s %v", bytes, readErr)
+	}
+	// Schema-filtered/library writes retain discovery diagnostics as well.
+	err = wmysql.NewWriter(&writers.WriterOptions{StrictConversion: true}).WriteSchema(model.Schemas[0])
+	if err == nil || !strings.Contains(err.Error(), trigger) {
+		t.Fatalf("filtered schema lost diagnostics: %v", err)
+	}
+	var warnings []string
+	_, err = wmysql.NewWriter(&writers.WriterOptions{Warning: func(s string) { warnings = append(warnings, s) }}).Statements(model)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{view, trigger, table} {
+		found := false
+		for _, warning := range warnings {
+			if strings.Contains(warning, want) {
+				found = true
+			}
+		}
+		if !found {
+			t.Errorf("no warning for %s: %v", want, warnings)
+		}
+	}
+}
+
+func TestLiveUnsupportedSQLModeFailsBeforeDDL(t *testing.T) {
+	conn := os.Getenv("RELSPEC_TEST_MYSQL_CONN")
+	if conn == "" {
+		t.Skip("RELSPEC_TEST_MYSQL_CONN is not set")
+	}
+	for _, mode := range []string{"NO_BACKSLASH_ESCAPES", "ANSI_QUOTES"} {
+		t.Run(mode, func(t *testing.T) {
+			cfg, err := driver.ParseDSN(conn)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if cfg.Params == nil {
+				cfg.Params = map[string]string{}
+			}
+			cfg.Params["sql_mode"] = "'" + mode + "'"
+			modeConn := cfg.FormatDSN()
+			model, err := rmysql.NewReader(&readers.ReaderOptions{ConnectionString: modeConn}).ReadDatabase()
+			if err != nil {
+				t.Fatal(err)
+			}
+			if _, err := wmysql.NewWriter(&writers.WriterOptions{StrictConversion: true}).Statements(model); err == nil || !strings.Contains(err.Error(), mode) {
+				t.Fatalf("source mode not diagnosed: %v", err)
+			}
+			db, err := sql.Open("mysql", conn)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer db.Close()
+			name := fmt.Sprintf("mode_%d", time.Now().UnixNano())
+			defer db.Exec("DROP TABLE IF EXISTS " + name)
+			target := models.InitDatabase(cfg.DBName)
+			s := models.InitSchema(cfg.DBName)
+			target.Schemas = append(target.Schemas, s)
+			table := models.InitTable(name, s.Name)
+			s.Tables = append(s.Tables, table)
+			c := models.InitColumn("id", name, s.Name)
+			c.Type = "int"
+			table.Columns[c.Name] = c
+			err = wmysql.NewWriter(&writers.WriterOptions{StrictConversion: true, Metadata: map[string]any{"connection_string": modeConn}}).WriteDatabase(target)
+			if err == nil || !strings.Contains(err.Error(), mode) {
+				t.Fatalf("target mode not rejected: %v", err)
+			}
+			var count int
+			if err := db.QueryRow("SELECT COUNT(*) FROM information_schema.TABLES WHERE TABLE_SCHEMA=? AND TABLE_NAME=?", cfg.DBName, name).Scan(&count); err != nil {
+				t.Fatal(err)
+			}
+			if count != 0 {
+				t.Fatal("mode rejection occurred after DDL")
+			}
+		})
+	}
+}