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.

2 files changed, 90 insertions, 68 deletions

diff --git a/pkg/commands/git_commands/patch.go b/pkg/commands/git_commands/patch.go
index a09f9bce6..0f8bfed9d 100644
--- a/pkg/commands/git_commands/patch.go
+++ b/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 {
diff --git a/pkg/commands/git_commands/rebase.go b/pkg/commands/git_commands/rebase.go
index 13c978a92..ead8da27a 100644
--- a/pkg/commands/git_commands/rebase.go
+++ b/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()
 	})