Avoid erroring when looking up config keys for nonexistent host

internal/config/config_file_test.go

@@ -2,7 +2,6 @@ package config
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"reflect"
 	"testing"
@@ -71,17 +70,29 @@ github.com:
 	eq(t, token, "OTOKEN")
 }
 
-func Test_parseConfig_notFound(t *testing.T) {
+func Test_parseConfig_hostFallback(t *testing.T) {
 	defer StubConfig(`---
-hosts:
-  example.com:
+git_protocol: ssh
+`, `---
+github.com:
+    user: monalisa
+    oauth_token: OTOKEN
+example.com:
     user: wronguser
     oauth_token: NOTTHIS
-`, "")()
+    git_protocol: https
+`)()
 	config, err := ParseConfig("config.yml")
 	eq(t, err, nil)
-	_, err = config.Get("github.com", "user")
-	eq(t, err, &NotFoundError{errors.New(`could not find config entry for "github.com"`)})
+	val, err := config.Get("example.com", "git_protocol")
+	eq(t, err, nil)
+	eq(t, val, "https")
+	val, err = config.Get("github.com", "git_protocol")
+	eq(t, err, nil)
+	eq(t, val, "ssh")
+	val, err = config.Get("nonexist.io", "git_protocol")
+	eq(t, err, nil)
+	eq(t, val, "ssh")
 }
 
 func Test_ParseConfig_migrateConfig(t *testing.T) {

internal/config/config_type.go

@@ -201,18 +201,21 @@ func (c *fileConfig) Root() *yaml.Node {
 
 func (c *fileConfig) Get(hostname, key string) (string, error) {
 	if hostname != "" {
-		hostCfg, err := c.configForHost(hostname)
-		if err != nil {
-			return "", err
-		}
-
-		hostValue, err := hostCfg.GetStringValue(key)
 		var notFound *NotFoundError
 
+		hostCfg, err := c.configForHost(hostname)
 		if err != nil && !errors.As(err, &notFound) {
 			return "", err
 		}
 
+		var hostValue string
+		if hostCfg != nil {
+			hostValue, err = hostCfg.GetStringValue(key)
+			if err != nil && !errors.As(err, &notFound) {
+				return "", err
+			}
+		}
+
 		if hostValue != "" {
 			return hostValue, nil
 		}
@@ -385,7 +388,7 @@ func (c *fileConfig) hostEntries() ([]*HostConfig, error) {
 	return hostConfigs, nil
 }
 
-// Hosts returns a list of all known hostnames configred in hosts.yml
+// Hosts returns a list of all known hostnames configured in hosts.yml
 func (c *fileConfig) Hosts() ([]string, error) {
 	entries, err := c.hostEntries()
 	if err != nil {