[client] Name the two config readers for what they do

ReadConfig and GetConfig differed in one thing — what happens when the file is
absent — and neither name said which was which:

- ReadConfig      -> ReadOrGenerateConfig  (reads it, or generates one in memory)
- GetConfig       -> GetExistingConfig     (reads it, or fails)

Three comments went with them:

- GetConfig's said "return with Config and if it was created. Errors out if it
  does not exist", which described a bool it does not return and a creation it
  never performs.
- ReadConfig's explained that it does not write, which is what a reader is
  supposed to do anyway.
- Server.getConfig's said it "errors out if it does not exist", which it does
  not — it resolves a default config, and now provisions the identity too.

client/internal/profilemanager/config.go

@@ -1130,8 +1130,8 @@ func update(input ConfigInput) (*Config, error) {
 	return config, nil
 }
 
-// GetConfig read config file and return with Config and if it was created. Errors out if it does not exist
-func GetConfig(configPath string) (*Config, error) {
+// GetExistingConfig reads and returns the config if it exists on disk. Fails otherwise.
+func GetExistingConfig(configPath string) (*Config, error) {
 	return readConfig(configPath, false)
 }
 
@@ -1219,13 +1219,9 @@ func CreateInMemoryConfig(input ConfigInput) (*Config, error) {
 	return createNewConfig(input)
 }
 
-// ReadConfig reads the profile config at configPath, resolving a default config
-// in memory when the file does not exist.
-//
-// It never writes. A caller that wants what it got back to be on disk calls
-// WriteOutConfig itself, and one that resolved a config for a peer to run with
-// calls EnsureIdentity first — see Server.getConfig for that pair.
-func ReadConfig(configPath string) (*Config, error) {
+// ReadOrGenerateConfig reads the profile config at configPath if it exists, or
+// generates one in memory from the defaults.
+func ReadOrGenerateConfig(configPath string) (*Config, error) {
 	return readConfig(configPath, true)
 }
 

client/internal/profilemanager/config_test.go

@@ -196,7 +196,7 @@ func TestWireguardPortZeroExplicit(t *testing.T) {
 	assert.Equal(t, 0, config.WgPort, "WgPort should be 0 when explicitly set by user")
 
 	// Verify it persists
-	readConfig, err := GetConfig(configPath)
+	readConfig, err := GetExistingConfig(configPath)
 	require.NoError(t, err)
 	assert.Equal(t, 0, readConfig.WgPort, "WgPort should remain 0 after reading from file")
 }

client/internal/profilemanager/config_would_change_test.go

@@ -108,8 +108,8 @@ func TestReadsDoNotWriteTheConfigBack(t *testing.T) {
 	denormalized := []byte(`{"WgIface":"wt0"}`)
 
 	for name, read := range map[string]func(string) (*Config, error){
-		"GetConfig":  GetConfig,
-		"ReadConfig": ReadConfig,
+		"GetExistingConfig":   GetExistingConfig,
+		"ReadOrGenerateConfig": ReadOrGenerateConfig,
 	} {
 		t.Run(name, func(t *testing.T) {
 			path := filepath.Join(t.TempDir(), "profile.json")
@@ -132,7 +132,7 @@ func TestReadsDoNotWriteTheConfigBack(t *testing.T) {
 func TestReadConfigDoesNotCreateTheFile(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "absent.json")
 
-	cfg, err := ReadConfig(path)
+	cfg, err := ReadOrGenerateConfig(path)
 	require.NoError(t, err)
 	require.Equal(t, DefaultManagementURL, cfg.ManagementURL.String())
 
@@ -198,7 +198,7 @@ func TestWouldChangeIgnoresURLSpelling(t *testing.T) {
 	})
 	require.NoError(t, err)
 
-	cfg, err := GetConfig(path)
+	cfg, err := GetExistingConfig(path)
 	require.NoError(t, err)
 
 	for _, spelling := range []string{
@@ -246,7 +246,7 @@ func TestUpdateConfigProvisionsAMissingIdentity(t *testing.T) {
 	require.NoError(t, err)
 
 	// Stand in for the logout, which zeroes the keys and writes the config out.
-	loggedOut, err := GetConfig(path)
+	loggedOut, err := GetExistingConfig(path)
 	require.NoError(t, err)
 	loggedOut.PrivateKey = ""
 	loggedOut.SSHKey = ""
@@ -257,7 +257,7 @@ func TestUpdateConfigProvisionsAMissingIdentity(t *testing.T) {
 	require.NotEmpty(t, cfg.PrivateKey, "the write path did not provision an identity")
 	require.NotEmpty(t, cfg.SSHKey)
 
-	persisted, err := GetConfig(path)
+	persisted, err := GetExistingConfig(path)
 	require.NoError(t, err)
 	require.Equal(t, cfg.PrivateKey, persisted.PrivateKey, "the provisioned identity was not persisted")
 }