Fix - provide default (empty) client config when default user config dir does not exist (temporalio#2266)

* Fix - provide default (empty) client config when default user config dir does not exist

* Restore conditional accidentally removed

Author: THardy98

contrib/envconfig/client_config_load.go

@@ -127,10 +127,8 @@ func LoadClientConfig(options LoadClientConfigOptions) (ClientConfig, error) {
 			file, _ = env.LookupEnv("TEMPORAL_CONFIG_FILE")
 		}
 		if file == "" {
-			var err error
-			if file, err = DefaultConfigFilePath(); err != nil {
-				return ClientConfig{}, err
-			}
+			// Get the default config file path. If it doesn't exist, the file path will be empty.
+			file = DefaultConfigFilePath()
 		}
 		// Load file, not exist is ok
 		if b, err := os.ReadFile(file); err == nil {
@@ -239,12 +237,13 @@ func LoadClientConfigProfile(options LoadClientConfigProfileOptions) (ClientConf
 const DefaultConfigFileProfile = "default"
 
 // DefaultConfigFilePath is the default config file path used. It is [os.UserConfigDir]/temporalio/temporal.toml.
-func DefaultConfigFilePath() (string, error) {
+// If the path does not exist, fallback to an empty file path.
+func DefaultConfigFilePath() string {
 	userDir, err := os.UserConfigDir()
 	if err != nil {
-		return "", fmt.Errorf("failed getting user config dir: %w", err)
+		return ""
 	}
-	return filepath.Join(userDir, "temporalio", "temporal.toml"), nil
+	return filepath.Join(userDir, "temporalio", "temporal.toml")
 }
 
 // EnvLookup abstracts environment variable lookup for [ClientConfigProfile.ApplyEnvVars]. [EnvLookupOS] is the common

contrib/envconfig/client_config_load_test.go

@@ -2,6 +2,7 @@ package envconfig_test
 
 import (
 	"os"
+	"runtime"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -170,6 +171,25 @@ disable_host_verification = true`
 	}, prof.GRPCMeta)
 }
 
+func TestLoadDefaultConfigFileNotExist(t *testing.T) {
+	// Unset default user config dir.
+	switch runtime.GOOS {
+	case "windows":
+		t.Setenv("AppData", "")
+	case "darwin", "ios":
+		t.Setenv("HOME", "")
+	case "plan9":
+		t.Setenv("home", "")
+	default: // Unix
+		t.Setenv("XDG_CONFIG_HOME", "")
+		t.Setenv("HOME", "")
+	}
+	// Load default config, config file does not exist
+	config, err := envconfig.LoadClientConfig(envconfig.LoadClientConfigOptions{})
+	require.NoError(t, err)
+	require.Equal(t, envconfig.ClientConfig{Profiles: make(map[string]*envconfig.ClientConfigProfile)}, config)
+}
+
 type EnvLookupMap map[string]string
 
 func (e EnvLookupMap) Environ() []string {