Refactor: simplify PrepareInteractiveRebaseCommand API

Instead of passing a bunch of different options in
PrepareInteractiveRebaseCommandOpts, where it was unclear how they interact if
several are set, have only a single field "instruction" which can be set to one
of various different instructions.

The functionality of replacing the entire todo file with our own is no longer
available; it is only possible to prepend todos to the existing file.

Also, instead of using different env vars for the various rebase operations that
we want to tell the daemon to do, use a single one that contains a json-encoded
struct with all available instructions. This makes the protocol much clearer,
and makes it easier to extend in the future.

pkg/app/daemon/daemon.go

@@ -1,8 +1,7 @@
 package daemon
 
 import (
-	"fmt"
-	"io"
+	"encoding/json"
 	"log"
 	"os"
 	"path/filepath"
@@ -32,39 +31,39 @@ const (
 
 const (
 	DaemonKindEnvKey string = "LAZYGIT_DAEMON_KIND"
-	RebaseTODOEnvKey string = "LAZYGIT_REBASE_TODO"
 
-	// The `PrependLinesEnvKey` env variable is set to `true` to tell our daemon
-	// to prepend the content of `RebaseTODOEnvKey` to the default `git-rebase-todo`
-	// file instead of using it as a replacement.
-	PrependLinesEnvKey string = "LAZYGIT_PREPEND_LINES"
+	// Contains a json-encoded instance of the InteractiveRebaseInstructions struct
+	InteractiveRebaseInstructionsEnvKey string = "LAZYGIT_DAEMON_INSTRUCTIONS"
+)
 
-	// If this is set, it tells lazygit to read the original todo file, and
-	// change the action for one or more entries in it. The value of the variable
-	// will have one or more lines of the form "Sha1:newAction", e.g.
-	// a02b54e1b7e7e8dd8bc1958c11ef4ee4df459ea4:edit
+// Exactly one of the fields in this struct is expected to be non-empty
+type InteractiveRebaseInstructions struct {
+	// If this is non-empty, this string is prepended to the git-rebase-todo
+	// file. The string is expected to have newlines at the end of each line.
+	LinesToPrependToRebaseTODO string
+
+	// If this is non-empty, it tells lazygit to read the original todo file, and
+	// change the action for one or more entries in it.
 	// The existing action of the todo to be changed is expected to be "pick".
-	//
-	// If this is used, the value of RebaseTODOEnvKey must be empty.
-	ChangeTodoActionEnvKey string = "LAZYGIT_CHANGE_TODO_ACTION"
+	ChangeTodoActions []ChangeTodoAction
 
 	// Can be set to the sha of a "pick" todo that will be moved down by one.
-	MoveTodoDownEnvKey string = "LAZYGIT_MOVE_COMMIT_DOWN"
+	ShaToMoveDown string
 
 	// Can be set to the sha of a "pick" todo that will be moved up by one.
-	MoveTodoUpEnvKey string = "LAZYGIT_MOVE_COMMIT_UP"
-)
+	ShaToMoveUp string
+}
+
+type ChangeTodoAction struct {
+	Sha       string
+	NewAction todo.TodoCommand
+}
 
 type Daemon interface {
 	Run() error
 }
 
-var logFile io.StringWriter
-
 func Handle(common *common.Common) {
-	logFile, _ = os.Create("/tmp/daemon-log.txt")
-	_, _ = logFile.WriteString("Hello Daemon\n")
-
 	d := getDaemon(common)
 	if d == nil {
 		return
@@ -118,43 +117,30 @@ func (self *rebaseDaemon) Run() error {
 }
 
 func (self *rebaseDaemon) writeTodoFile(path string) error {
-	if changeTodoActionEnvValue := os.Getenv(ChangeTodoActionEnvKey); changeTodoActionEnvValue != "" {
-		return self.changeTodoAction(path, changeTodoActionEnvValue)
-	} else if shaToMoveDown := os.Getenv(MoveTodoDownEnvKey); shaToMoveDown != "" {
-		_, _ = logFile.WriteString(fmt.Sprintf("Moving commit down: %s\n", shaToMoveDown))
-		return utils.MoveTodoDown(path, shaToMoveDown, todo.Pick)
-	} else if shaToMoveUp := os.Getenv(MoveTodoUpEnvKey); shaToMoveUp != "" {
-		_, _ = logFile.WriteString(fmt.Sprintf("Moving commit up: %s\n", shaToMoveUp))
-		return utils.MoveTodoUp(path, shaToMoveUp, todo.Pick)
-	} else {
-		todoContent := []byte(os.Getenv(RebaseTODOEnvKey))
-
-		prependLines := os.Getenv(PrependLinesEnvKey) != ""
-		if prependLines {
-			existingContent, err := os.ReadFile(path)
-			if err != nil {
-				return err
-			}
-
-			todoContent = append(todoContent, existingContent...)
-		}
-
-		return os.WriteFile(path, todoContent, 0o644)
+	jsonData := os.Getenv(InteractiveRebaseInstructionsEnvKey)
+	instructions := InteractiveRebaseInstructions{}
+	err := json.Unmarshal([]byte(jsonData), &instructions)
+	if err != nil {
+		return err
 	}
+
+	if instructions.LinesToPrependToRebaseTODO != "" {
+		return utils.PrependStrToTodoFile(path, []byte(instructions.LinesToPrependToRebaseTODO))
+	} else if len(instructions.ChangeTodoActions) != 0 {
+		return self.changeTodoAction(path, instructions.ChangeTodoActions)
+	} else if instructions.ShaToMoveDown != "" {
+		return utils.MoveTodoDown(path, instructions.ShaToMoveDown, todo.Pick)
+	} else if instructions.ShaToMoveUp != "" {
+		return utils.MoveTodoUp(path, instructions.ShaToMoveUp, todo.Pick)
+	}
+
+	self.c.Log.Error("No instructions were given to daemon")
+	return nil
 }
 
-func (self *rebaseDaemon) changeTodoAction(path string, changeTodoActionEnvValue string) error {
-	lines := strings.Split(changeTodoActionEnvValue, "\n")
-	for _, line := range lines {
-		fields := strings.Split(line, ":")
-		if len(fields) != 2 {
-			return fmt.Errorf("Unexpected value for %s: %s", ChangeTodoActionEnvKey, changeTodoActionEnvValue)
-		}
-		sha, newAction := fields[0], self.actionFromString(fields[1])
-		if int(newAction) == 0 {
-			return fmt.Errorf("Unknown action in %s", changeTodoActionEnvValue)
-		}
-		if err := utils.EditRebaseTodo(path, sha, todo.Pick, newAction); err != nil {
+func (self *rebaseDaemon) changeTodoAction(path string, changeTodoActions []ChangeTodoAction) error {
+	for _, c := range changeTodoActions {
+		if err := utils.EditRebaseTodo(path, c.Sha, todo.Pick, c.NewAction); err != nil {
 			return err
 		}
 	}
@@ -162,16 +148,6 @@ func (self *rebaseDaemon) changeTodoAction(path string, changeTodoActionEnvValue
 	return nil
 }
 
-func (self *rebaseDaemon) actionFromString(actionString string) todo.TodoCommand {
-	for t := todo.Pick; t < todo.Comment; t++ {
-		if t.String() == actionString {
-			return t
-		}
-	}
-
-	return 0
-}
-
 func gitDir() string {
 	dir := env.GetGitDirEnv()
 	if dir == "" {

pkg/commands/git_commands/patch.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/fsmiamoto/git-todo-parser/todo"
 	"github.com/go-errors/errors"
+	"github.com/jesseduffield/lazygit/pkg/app/daemon"
 	"github.com/jesseduffield/lazygit/pkg/commands/models"
 	"github.com/jesseduffield/lazygit/pkg/commands/patch"
 	"github.com/jesseduffield/lazygit/pkg/commands/types/enums"
@@ -107,9 +108,11 @@ func (self *PatchCommands) MovePatchToSelectedCommit(commits []*models.Commit, s
 	err := self.rebase.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot:  commits[baseIndex].Sha,
 		overrideEditor: true,
-		changeTodoActions: []ChangeTodoAction{
-			{sha: commits[sourceCommitIdx].Sha, newAction: todo.Edit},
-			{sha: commits[destinationCommitIdx].Sha, newAction: todo.Edit},
+		instruction: ChangeTodoActionsInstruction{
+			actions: []daemon.ChangeTodoAction{
+				{Sha: commits[sourceCommitIdx].Sha, NewAction: todo.Edit},
+				{Sha: commits[destinationCommitIdx].Sha, NewAction: todo.Edit},
+			},
 		},
 	}).Run()
 	if err != nil {

pkg/commands/git_commands/rebase.go

@@ -1,6 +1,7 @@
 package git_commands
 
 import (
+	"encoding/json"
 	"fmt"
 	"path/filepath"
 	"strings"
@@ -57,11 +58,11 @@ func (self *RebaseCommands) RewordCommit(commits []*models.Commit, index int, me
 func (self *RebaseCommands) RewordCommitInEditor(commits []*models.Commit, index int) (oscommands.ICmdObj, error) {
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot: getBaseShaOrRoot(commits, index+1),
-		changeTodoActions: []ChangeTodoAction{
-			{
-				sha:       commits[index].Sha,
-				newAction: todo.Reword,
-			},
+		instruction: ChangeTodoActionsInstruction{
+			actions: []daemon.ChangeTodoAction{{
+				Sha:       commits[index].Sha,
+				NewAction: todo.Reword,
+			}},
 		},
 	}), nil
 }
@@ -103,8 +104,8 @@ func (self *RebaseCommands) MoveCommitDown(commits []*models.Commit, index int)
 
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot:  baseShaOrRoot,
+		instruction:    MoveDownInstruction{sha: commits[index].Sha},
 		overrideEditor: true,
-		moveDown:       commits[index].Sha,
 	}).Run()
 }
 
@@ -113,8 +114,8 @@ func (self *RebaseCommands) MoveCommitUp(commits []*models.Commit, index int) er
 
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot:  baseShaOrRoot,
+		instruction:    MoveUpInstruction{sha: commits[index].Sha},
 		overrideEditor: true,
-		moveUp:         commits[index].Sha,
 	}).Run()
 }
 
@@ -127,12 +128,14 @@ func (self *RebaseCommands) InteractiveRebase(commits []*models.Commit, index in
 	baseShaOrRoot := getBaseShaOrRoot(commits, baseIndex)
 
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
-		baseShaOrRoot:  baseShaOrRoot,
+		baseShaOrRoot: baseShaOrRoot,
+		instruction: ChangeTodoActionsInstruction{
+			actions: []daemon.ChangeTodoAction{{
+				Sha:       commits[index].Sha,
+				NewAction: action,
+			}},
+		},
 		overrideEditor: true,
-		changeTodoActions: []ChangeTodoAction{{
-			sha:       commits[index].Sha,
-			newAction: action,
-		}},
 	}).Run()
 }
 
@@ -140,59 +143,72 @@ func (self *RebaseCommands) EditRebase(branchRef string) error {
 	commands := []TodoLine{{Action: "break"}}
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot: branchRef,
-		todoLines:     commands,
-		prepend:       true,
+		instruction:   PrependLinesInstruction{todoLines: commands},
 	}).Run()
 }
 
-type ChangeTodoAction struct {
-	sha       string
-	newAction todo.TodoCommand
+type InteractiveRebaseInstruction interface {
+	// Add our data to the instructions struct, and return a log string
+	serialize(instructions *daemon.InteractiveRebaseInstructions) string
+}
+
+type PrependLinesInstruction struct {
+	todoLines []TodoLine
+}
+
+func (self PrependLinesInstruction) serialize(instructions *daemon.InteractiveRebaseInstructions) string {
+	todoStr := TodoLinesToString(self.todoLines)
+	instructions.LinesToPrependToRebaseTODO = todoStr
+	return fmt.Sprintf("Creating TODO file for interactive rebase: \n\n%s", todoStr)
+}
+
+type ChangeTodoActionsInstruction struct {
+	actions []daemon.ChangeTodoAction
+}
+
+func (self ChangeTodoActionsInstruction) serialize(instructions *daemon.InteractiveRebaseInstructions) string {
+	instructions.ChangeTodoActions = self.actions
+	changeTodoStr := strings.Join(slices.Map(self.actions, func(c daemon.ChangeTodoAction) string {
+		return fmt.Sprintf("%s:%s", c.Sha, c.NewAction)
+	}), "\n")
+	return fmt.Sprintf("Changing TODO actions: %s", changeTodoStr)
+}
+
+type MoveDownInstruction struct {
+	sha string
+}
+
+func (self MoveDownInstruction) serialize(instructions *daemon.InteractiveRebaseInstructions) string {
+	instructions.ShaToMoveDown = self.sha
+	return fmt.Sprintf("Moving TODO down: %s", self.sha)
+}
+
+type MoveUpInstruction struct {
+	sha string
+}
+
+func (self MoveUpInstruction) serialize(instructions *daemon.InteractiveRebaseInstructions) string {
+	instructions.ShaToMoveUp = self.sha
+	return fmt.Sprintf("Moving TODO up: %s", self.sha)
 }
 
 type PrepareInteractiveRebaseCommandOpts struct {
-	baseShaOrRoot     string
-	todoLines         []TodoLine
-	overrideEditor    bool
-	prepend           bool
-	changeTodoActions []ChangeTodoAction
-	moveDown          string
-	moveUp            string
+	baseShaOrRoot  string
+	instruction    InteractiveRebaseInstruction
+	overrideEditor bool
 }
 
 // PrepareInteractiveRebaseCommand returns the cmd for an interactive rebase
 // we tell git to run lazygit to edit the todo list, and we pass the client
 // lazygit a todo string to write to the todo file
 func (self *RebaseCommands) PrepareInteractiveRebaseCommand(opts PrepareInteractiveRebaseCommandOpts) oscommands.ICmdObj {
-	todo := self.buildTodo(opts.todoLines)
 	ex := oscommands.GetLazygitPath()
-	prependLines := ""
-	if opts.prepend {
-		prependLines = "TRUE"
-	}
 
 	debug := "FALSE"
 	if self.Debug {
 		debug = "TRUE"
 	}
 
-	changeTodoValue := strings.Join(slices.Map(opts.changeTodoActions, func(c ChangeTodoAction) string {
-		return fmt.Sprintf("%s:%s", c.sha, c.newAction)
-	}), "\n")
-
-	moveDownValue := ""
-	if opts.moveDown != "" {
-		moveDownValue = opts.moveDown
-	}
-	moveUpValue := ""
-	if opts.moveUp != "" {
-		moveUpValue = opts.moveUp
-	}
-
-	if todo != "" && changeTodoValue != "" {
-		panic("It's not allowed to pass both todoLines and changeActionOpts")
-	}
-
 	rebaseMergesArg := " --rebase-merges"
 	if self.version.IsOlderThan(2, 22, 0) {
 		rebaseMergesArg = ""
@@ -204,25 +220,24 @@ func (self *RebaseCommands) PrepareInteractiveRebaseCommand(opts PrepareInteract
 	cmdObj := self.cmd.New(cmdStr)
 
 	gitSequenceEditor := ex
-	if todo != "" {
-		self.os.LogCommand(fmt.Sprintf("Creating TODO file for interactive rebase: \n\n%s", todo), false)
-	} else if changeTodoValue != "" {
-		self.os.LogCommand(fmt.Sprintf("Changing TODO action: %s", changeTodoValue), false)
-	} else if moveDownValue != "" {
-		self.os.LogCommand(fmt.Sprintf("Moving TODO down: %s", moveDownValue), false)
-	} else if moveUpValue != "" {
-		self.os.LogCommand(fmt.Sprintf("Moving TODO up: %s", moveUpValue), false)
+
+	if opts.instruction != nil {
+		instructions := daemon.InteractiveRebaseInstructions{}
+		logStr := opts.instruction.serialize(&instructions)
+		jsonData, err := json.Marshal(instructions)
+		if err == nil {
+			envVar := fmt.Sprintf("%s=%s", daemon.InteractiveRebaseInstructionsEnvKey, jsonData)
+			cmdObj.AddEnvVars(envVar)
+			self.os.LogCommand(logStr, false)
+		} else {
+			self.Log.Error(err)
+		}
 	} else {
 		gitSequenceEditor = "true"
 	}
 
 	cmdObj.AddEnvVars(
 		daemon.DaemonKindEnvKey+"="+string(daemon.InteractiveRebase),
-		daemon.RebaseTODOEnvKey+"="+todo,
-		daemon.PrependLinesEnvKey+"="+prependLines,
-		daemon.ChangeTodoActionEnvKey+"="+changeTodoValue,
-		daemon.MoveTodoDownEnvKey+"="+moveDownValue,
-		daemon.MoveTodoUpEnvKey+"="+moveUpValue,
 		"DEBUG="+debug,
 		"LANG=en_US.UTF-8",   // Force using EN as language
 		"LC_ALL=en_US.UTF-8", // Force using EN as language
@@ -297,10 +312,12 @@ func (self *RebaseCommands) BeginInteractiveRebaseForCommit(commits []*models.Co
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot:  getBaseShaOrRoot(commits, commitIndex+1),
 		overrideEditor: true,
-		changeTodoActions: []ChangeTodoAction{{
-			sha:       commits[commitIndex].Sha,
-			newAction: todo.Edit,
-		}},
+		instruction: ChangeTodoActionsInstruction{
+			actions: []daemon.ChangeTodoAction{{
+				Sha:       commits[commitIndex].Sha,
+				NewAction: todo.Edit,
+			}},
+		},
 	}).Run()
 }
 
@@ -393,11 +410,13 @@ func (self *RebaseCommands) CherryPickCommits(commits []*models.Commit) error {
 
 	return self.PrepareInteractiveRebaseCommand(PrepareInteractiveRebaseCommandOpts{
 		baseShaOrRoot: "HEAD",
-		todoLines:     todoLines,
+		instruction: PrependLinesInstruction{
+			todoLines: todoLines,
+		},
 	}).Run()
 }
 
-func (self *RebaseCommands) buildTodo(todoLines []TodoLine) string {
+func TodoLinesToString(todoLines []TodoLine) string {
 	lines := slices.Map(todoLines, func(todoLine TodoLine) string {
 		return todoLine.ToString()
 	})

pkg/utils/rebase_todo.go

@@ -63,6 +63,16 @@ func WriteRebaseTodoFile(fileName string, todos []todo.Todo) error {
 	return err
 }
 
+func PrependStrToTodoFile(filePath string, linesToPrepend []byte) error {
+	existingContent, err := os.ReadFile(filePath)
+	if err != nil {
+		return err
+	}
+
+	linesToPrepend = append(linesToPrepend, existingContent...)
+	return os.WriteFile(filePath, linesToPrepend, 0o644)
+}
+
 func MoveTodoDown(fileName string, sha string, action todo.TodoCommand) error {
 	todos, err := ReadRebaseTodoFile(fileName)
 	if err != nil {