fix: preserve MySQL schema fidelity

pkg/readers/mysql/expressions_test.go

@@ -0,0 +1,54 @@
+package mysql
+
+import "testing"
+
+func TestUnescapeExpression(t *testing.T) {
+	for _, tc := range []struct{ input, want string }{
+		{`_utf8mb4\'one\\ntwo\'`, `_utf8mb4'one\ntwo'`},
+		{`concat(\'don\\\'t\',\' change\')`, `concat('don\'t',' change')`},
+		{`(uuid())`, `(uuid())`},
+	} {
+		if got := unescapeExpression(tc.input); got != tc.want {
+			t.Errorf("%q: got %q want %q", tc.input, got, tc.want)
+		}
+	}
+}
+
+func TestNativeColumnDefaults(t *testing.T) {
+	create := "CREATE TABLE `odd(table` (\n" +
+		" `a,b` varbinary(8) DEFAULT 0x0027FF,\n" +
+		" `tick``name` varchar(30) DEFAULT 'don''t, (split)',\n" +
+		" `expr` varchar(30) DEFAULT (concat('DEFAULT, ', (uuid()))),\n" +
+		" `generated` varchar(30) GENERATED ALWAYS AS (concat('DEFAULT',`expr`)) VIRTUAL,\n" +
+		" `new\nline` int DEFAULT 3,\n" +
+		" PRIMARY KEY (`a,b`)\n) ENGINE=InnoDB"
+	got := columnDefaults(create)
+	want := map[string]string{"a,b": "0x0027FF", "tick`name": "'don''t, (split)'", "expr": "(concat('DEFAULT, ', (uuid())))", "new\nline": "3"}
+	if len(got) != len(want) {
+		t.Fatalf("defaults: %v", got)
+	}
+	for name, value := range want {
+		if got[name] != value {
+			t.Errorf("%s: got %q want %q", name, got[name], value)
+		}
+	}
+}
+
+func TestNativeOptionsIgnoreQuotedValues(t *testing.T) {
+	create := "CREATE TABLE `WITH PARSER` (`STORAGE` int COMMENT 'KEY_BLOCK_SIZE', KEY `ENGINE_ATTRIBUTE` (`STORAGE`) WITH PARSER `ngram`) ENGINE=InnoDB"
+	options := unsupportedNativeOptions(create)
+	if len(options) != 1 || options[0] != "WITH PARSER" {
+		t.Fatalf("native options: %v", options)
+	}
+}
+
+func TestNativeAutoIncrementIgnoresQuotedValues(t *testing.T) {
+	for _, tc := range []struct{ create, want string }{
+		{"CREATE TABLE `x` (`id` bigint AUTO_INCREMENT) ENGINE=InnoDB AUTO_INCREMENT=18446744073709551615", "18446744073709551615"},
+		{"CREATE TABLE `x` (`id` bigint AUTO_INCREMENT) COMMENT='AUTO_INCREMENT=12'", "1"},
+	} {
+		if got := autoIncrementValue(tc.create); got != tc.want {
+			t.Errorf("got %s want %s", got, tc.want)
+		}
+	}
+}