Pass envs to mysqld process

changelog/23.0/23.0.0/summary.md

@@ -71,3 +71,9 @@ ALTER USER 'vt_repl'@'%' IDENTIFIED WITH caching_sha2_password BY 'your-existing
 ```
 
 In future Vitess versions, the `mysql_native_password` authentication plugin will be disabled for managed MySQL instances.
+
+#### <a id="mysql-timezone-env"/>MySQL timezone environment propagation</a>
+
+Fixed a bug where environment variables like `TZ` were not propagated from mysqlctl to the mysqld process.
+As a result, timezone settings from the environment were previously ignored. Now mysqld correctly inherits environment variables.
+⚠️ Deployments that relied on the old behavior and explicitly set a non-UTC timezone may see changes in how DATETIME values are interpreted. To preserve compatibility, set `TZ=UTC` explicitly in MySQL pods.

go/vt/mysqlctl/mysqld.go

@@ -1264,17 +1264,19 @@ func (mysqld *Mysqld) OnTerm(f func()) {
 }
 
 func buildLdPaths() ([]string, error) {
+	baseEnv := os.Environ()
+
 	vtMysqlRoot, err := vtenv.VtMysqlRoot()
 	if err != nil {
-		return []string{}, err
+		return baseEnv, err
 	}
 
 	ldPaths := []string{
 		fmt.Sprintf("LD_LIBRARY_PATH=%s/lib/mysql", vtMysqlRoot),
 		os.ExpandEnv("LD_PRELOAD=$LD_PRELOAD"),
 	}
 
-	return ldPaths, nil
+	return append(baseEnv, ldPaths...), nil
 }
 
 // GetVersionString is part of the MysqlExecutor interface.

go/vt/mysqlctl/mysqld_test.go

@@ -350,3 +350,12 @@ func TestGetMycnfTemplateMySQL9(t *testing.T) {
 	assert.Contains(t, template, "# This file is auto-included when MySQL 9.0 or later is detected.")
 	assert.NotContains(t, template, "mysql_native_password = ON")
 }
+
+func TestBuildLdPathsTZ(t *testing.T) {
+	os.Setenv("TZ", "Europe/Berlin")
+	defer os.Unsetenv("TZ")
+
+	env, err := buildLdPaths()
+	assert.NoError(t, err)
+	assert.Contains(t, env, "TZ=Europe/Berlin")
+}