cmd/gitannex: Support synonyms of config values

cmd/gitannex/gitannex.go

@@ -110,12 +110,32 @@ func (m *messageParser) finalParameter() string {
 // configDefinition describes a configuration value required by this command. We
 // use "GETCONFIG" messages to query git-annex for these values at runtime.
 type configDefinition struct {
-	name         string
+	names        []string
 	description  string
 	destination  *string
 	defaultValue *string
 }
 
+func (c *configDefinition) getCanonicalName() string {
+	if len(c.names) < 1 {
+		panic(fmt.Errorf("configDefinition must have at least one name: %v", c))
+	}
+	return c.names[0]
+}
+
+// fullDescription returns a single-line, human-readable description for this
+// config. The returned string begins with a list of synonyms and ends with
+// `c.description`.
+func (c *configDefinition) fullDescription() string {
+	if len(c.names) <= 1 {
+		return c.description
+	}
+	// Exclude the canonical name from the list of synonyms.
+	synonyms := c.names[1:len(c.names)]
+	commaSeparatedSynonyms := strings.Join(synonyms, ", ")
+	return fmt.Sprintf("(synonyms: %s) %s", commaSeparatedSynonyms, c.description)
+}
+
 // server contains this command's current state.
 type server struct {
 	reader *bufio.Reader
@@ -274,7 +294,7 @@ func (s *server) getRequiredConfigs() []configDefinition {
 
 	return []configDefinition{
 		{
-			"rcloneremotename",
+			[]string{"rcloneremotename", "target"},
 			"Name of the rclone remote to use. " +
 				"Must match a remote known to rclone. " +
 				"(Note that rclone remotes are a distinct concept from git-annex remotes.)",
@@ -282,7 +302,7 @@ func (s *server) getRequiredConfigs() []configDefinition {
 			nil,
 		},
 		{
-			"rcloneprefix",
+			[]string{"rcloneprefix", "prefix"},
 			"Directory where rclone will write git-annex content. " +
 				fmt.Sprintf("If not specified, defaults to %q. ", defaultRclonePrefix) +
 				"This directory will be created on init if it does not exist.",
@@ -290,7 +310,7 @@ func (s *server) getRequiredConfigs() []configDefinition {
 			&defaultRclonePrefix,
 		},
 		{
-			"rclonelayout",
+			[]string{"rclonelayout", "rclone_layout"},
 			"Defines where, within the rcloneprefix directory, rclone will write git-annex content. " +
 				fmt.Sprintf("Must be one of %v. ", allLayoutModes()) +
 				fmt.Sprintf("If empty, defaults to %q.", defaultRcloneLayout),
@@ -309,27 +329,35 @@ func (s *server) queryConfigs() error {
 	// Send a "GETCONFIG" message for each required config and parse git-annex's
 	// "VALUE" response.
 	for _, config := range s.getRequiredConfigs() {
-		s.sendMsg(fmt.Sprintf("GETCONFIG %s", config.name))
+		var valueReceived bool
+		// Try each of the config's names in sequence, starting with the
+		// canonical name.
+		for _, configName := range config.names {
+			s.sendMsg(fmt.Sprintf("GETCONFIG %s", configName))
 
-		message, err := s.getMsg()
+			message, err := s.getMsg()
-		if err != nil {
+			if err != nil {
-			return err
+				return err
-		}
+			}
 
-		valueKeyword, err := message.nextSpaceDelimitedParameter()
+			valueKeyword, err := message.nextSpaceDelimitedParameter()
-		if err != nil || valueKeyword != "VALUE" {
+			if err != nil || valueKeyword != "VALUE" {
-			return fmt.Errorf("failed to parse config value: %s %s", valueKeyword, message.line)
+				return fmt.Errorf("failed to parse config value: %s %s", valueKeyword, message.line)
-		}
+			}
 
-		value := message.finalParameter()
+			value := message.finalParameter()
-		if value == "" && config.defaultValue == nil {
+			if value != "" {
-			return fmt.Errorf("config value of %q must not be empty", config.name)
+				*config.destination = value
+				valueReceived = true
+				break
+			}
 		}
-		if value == "" {
+		if !valueReceived {
+			if config.defaultValue == nil {
+				return fmt.Errorf("did not receive a non-empty config value for %q", config.getCanonicalName())
+			}
 			*config.destination = *config.defaultValue
-			continue
 		}
-		*config.destination = value
 	}
 
 	s.configsDone = true
@@ -349,7 +377,7 @@ func (s *server) handlePrepare() error {
 // in sync with `handlePrepare()`.
 func (s *server) handleListConfigs() {
 	for _, config := range s.getRequiredConfigs() {
-		s.sendMsg(fmt.Sprintf("CONFIG %s %s", config.name, config.description))
+		s.sendMsg(fmt.Sprintf("CONFIG %s %s", config.getCanonicalName(), config.fullDescription()))
 	}
 	s.sendMsg("CONFIGEND")
 }

cmd/gitannex/gitannex_test.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"sync"
 	"testing"
@@ -192,6 +193,63 @@ func TestMessageParser(t *testing.T) {
 	}
 }
 
+func TestConfigDefinitionOneName(t *testing.T) {
+	var parsed string
+	var defaultValue = "abc"
+
+	configFoo := configDefinition{
+		names:        []string{"foo"},
+		description:  "The foo config is utterly useless.",
+		destination:  &parsed,
+		defaultValue: &defaultValue,
+	}
+
+	assert.Equal(t, "foo",
+		configFoo.getCanonicalName())
+
+	assert.Equal(t,
+		configFoo.description,
+		configFoo.fullDescription())
+}
+
+func TestConfigDefinitionTwoNames(t *testing.T) {
+	var parsed string
+	var defaultValue = "abc"
+
+	configFoo := configDefinition{
+		names:        []string{"foo", "bar"},
+		description:  "The foo config is utterly useless.",
+		destination:  &parsed,
+		defaultValue: &defaultValue,
+	}
+
+	assert.Equal(t, "foo",
+		configFoo.getCanonicalName())
+
+	assert.Equal(t,
+		"(synonyms: bar) The foo config is utterly useless.",
+		configFoo.fullDescription())
+}
+
+func TestConfigDefinitionThreeNames(t *testing.T) {
+	var parsed string
+	var defaultValue = "abc"
+
+	configFoo := configDefinition{
+		names:        []string{"foo", "bar", "baz"},
+		description:  "The foo config is utterly useless.",
+		destination:  &parsed,
+		defaultValue: &defaultValue,
+	}
+
+	assert.Equal(t, "foo",
+		configFoo.getCanonicalName())
+
+	assert.Equal(t,
+		`(synonyms: bar, baz) The foo config is utterly useless.`,
+		configFoo.fullDescription())
+}
+
 type testState struct {
 	t                *testing.T
 	server           *server
@@ -224,6 +282,12 @@ func (h *testState) requireReadLineExact(line string) {
 	require.Equal(h.t, line+"\n", receivedLine)
 }
 
+func (h *testState) requireReadLine() string {
+	receivedLine, err := h.mockStdoutReader.ReadString('\n')
+	require.NoError(h.t, err)
+	return receivedLine
+}
+
 func (h *testState) requireWriteLine(line string) {
 	_, err := h.mockStdinW.Write([]byte(line + "\n"))
 	require.NoError(h.t, err)
@@ -269,6 +333,34 @@ var localBackendTestCases = []testCase{
 			require.NoError(t, h.mockStdinW.Close())
 		},
 	},
+	{
+		label: "HandlesListConfigs",
+		testProtocolFunc: func(t *testing.T, h *testState) {
+			h.preconfigureServer()
+
+			h.requireReadLineExact("VERSION 1")
+			h.requireWriteLine("INITREMOTE")
+			h.requireReadLineExact("INITREMOTE-SUCCESS")
+
+			h.requireWriteLine("LISTCONFIGS")
+
+			require.Regexp(t,
+				regexp.MustCompile(`^CONFIG rcloneremotename \(synonyms: target\) (.|\n)*$`),
+				h.requireReadLine(),
+			)
+			require.Regexp(t,
+				regexp.MustCompile(`^CONFIG rcloneprefix \(synonyms: prefix\) (.|\n)*$`),
+				h.requireReadLine(),
+			)
+			require.Regexp(t,
+				regexp.MustCompile(`^CONFIG rclonelayout \(synonyms: rclone_layout\) (.|\n)*$`),
+				h.requireReadLine(),
+			)
+			h.requireReadLineExact("CONFIGEND")
+
+			require.NoError(t, h.mockStdinW.Close())
+		},
+	},
 	{
 		label: "HandlesPrepare",
 		testProtocolFunc: func(t *testing.T, h *testState) {
@@ -297,6 +389,38 @@ var localBackendTestCases = []testCase{
 			require.NoError(t, h.mockStdinW.Close())
 		},
 	},
+	{
+		label: "HandlesPrepareWithSynonyms",
+		testProtocolFunc: func(t *testing.T, h *testState) {
+			h.requireReadLineExact("VERSION 1")
+			h.requireWriteLine("EXTENSIONS INFO") // Advertise that we support the INFO extension
+			h.requireReadLineExact("EXTENSIONS")
+
+			if !h.server.extensionInfo {
+				t.Errorf("expected INFO extension to be enabled")
+				return
+			}
+
+			h.requireWriteLine("PREPARE")
+			h.requireReadLineExact("GETCONFIG rcloneremotename")
+			// TODO check what git-annex does when asked for a config value it does not have.
+			h.requireWriteLine("VALUE")
+			h.requireReadLineExact("GETCONFIG target")
+			h.requireWriteLine("VALUE " + h.remoteName)
+
+			h.requireReadLineExact("GETCONFIG rcloneprefix")
+			h.requireWriteLine("VALUE " + h.localFsDir)
+			h.requireReadLineExact("GETCONFIG rclonelayout")
+			h.requireWriteLine("VALUE foo")
+			h.requireReadLineExact("PREPARE-SUCCESS")
+
+			require.Equal(t, h.server.configRcloneRemoteName, h.remoteName)
+			require.Equal(t, h.server.configPrefix, h.localFsDir)
+			require.True(t, h.server.configsDone)
+
+			require.NoError(t, h.mockStdinW.Close())
+		},
+	},
 	{
 		label: "HandlesPrepareAndDoesNotTrimWhitespaceFromValue",
 		testProtocolFunc: func(t *testing.T, h *testState) {
@@ -322,6 +446,8 @@ var localBackendTestCases = []testCase{
 
 			h.requireReadLineExact("GETCONFIG rclonelayout")
 			h.requireWriteLine("VALUE")
+			h.requireReadLineExact("GETCONFIG rclone_layout")
+			h.requireWriteLine("VALUE")
 
 			h.requireReadLineExact("PREPARE-SUCCESS")