Construct arg vector manually rather than parse string

By constructing an arg vector manually, we no longer need to quote arguments

Mandate that args must be passed when building a command

Now you need to provide an args array when building a command.
There are a handful of places where we need to deal with a string,
such as with user-defined custom commands, and for those we now require
that at the callsite they use str.ToArgv to do that. I don't want
to provide a method out of the box for it because I want to discourage its
use.

For some reason we were invoking a command through a shell when amending a
commit, and I don't believe we needed to do that as there was nothing user-
supplied about the command. So I've switched to using a regular command out-
side the shell there

pkg/gui/controllers/helpers/diff_helper.go

@@ -1,8 +1,6 @@
 package helpers
 
 import (
-	"fmt"
-
 	"github.com/jesseduffield/lazygit/pkg/gui/context"
 	"github.com/jesseduffield/lazygit/pkg/gui/modes/diffing"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
@@ -19,27 +17,29 @@ func NewDiffHelper(c *HelperCommon) *DiffHelper {
 	}
 }
 
-func (self *DiffHelper) DiffStr() string {
-	output := self.c.Modes().Diffing.Ref
+func (self *DiffHelper) DiffArgs() []string {
+	output := []string{self.c.Modes().Diffing.Ref}
 
 	right := self.currentDiffTerminal()
 	if right != "" {
-		output += " " + right
+		output = append(output, right)
 	}
 
 	if self.c.Modes().Diffing.Reverse {
-		output += " -R"
+		output = append(output, "-R")
 	}
 
 	if self.c.State().GetIgnoreWhitespaceInDiffView() {
-		output += " --ignore-all-space"
+		output = append(output, "--ignore-all-space")
 	}
 
+	output = append(output, "--")
+
 	file := self.currentlySelectedFilename()
 	if file != "" {
-		output += " -- " + file
+		output = append(output, file)
 	} else if self.c.Modes().Filtering.Active() {
-		output += " -- " + self.c.Modes().Filtering.GetPath()
+		output = append(output, self.c.Modes().Filtering.GetPath())
 	}
 
 	return output
@@ -51,9 +51,7 @@ func (self *DiffHelper) ExitDiffMode() error {
 }
 
 func (self *DiffHelper) RenderDiff() error {
-	cmdObj := self.c.OS().Cmd.New(
-		fmt.Sprintf("git diff --submodule --no-ext-diff --color %s", self.DiffStr()),
-	)
+	cmdObj := self.c.Git().Diff.DiffCmdObj(self.DiffArgs())
 	task := types.NewRunPtyTask(cmdObj.GetCmd())
 
 	return self.c.RenderToMainViews(types.RefreshMainOpts{

pkg/gui/controllers/helpers/gpg_helper.go

@@ -21,11 +21,10 @@ func NewGpgHelper(c *HelperCommon) *GpgHelper {
 // WithWaitingStatus we get stuck there and can't return to lazygit. We could
 // fix this bug, or just stop running subprocesses from within there, given that
 // we don't need to see a loading status if we're in a subprocess.
-// TODO: we shouldn't need to use a shell here, but looks like that NewShell function contains some windows specific quoting stuff. We should centralise that.
 func (self *GpgHelper) WithGpgHandling(cmdObj oscommands.ICmdObj, waitingStatus string, onSuccess func() error) error {
 	useSubprocess := self.c.Git().Config.UsingGpg()
 	if useSubprocess {
-		success, err := self.c.RunSubprocess(self.c.OS().Cmd.NewShell(cmdObj.ToString()))
+		success, err := self.c.RunSubprocess(cmdObj)
 		if success && onSuccess != nil {
 			if err := onSuccess(); err != nil {
 				return err
@@ -42,8 +41,6 @@ func (self *GpgHelper) WithGpgHandling(cmdObj oscommands.ICmdObj, waitingStatus
 }
 
 func (self *GpgHelper) runAndStream(cmdObj oscommands.ICmdObj, waitingStatus string, onSuccess func() error) error {
-	cmdObj = self.c.OS().Cmd.NewShell(cmdObj.ToString())
-
 	return self.c.WithWaitingStatus(waitingStatus, func() error {
 		if err := cmdObj.StreamOutput().Run(); err != nil {
 			_ = self.c.Refresh(types.RefreshOptions{Mode: types.ASYNC})

pkg/gui/controllers/helpers/mode_helper.go

@@ -2,6 +2,7 @@ package helpers
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/jesseduffield/generics/slices"
 	"github.com/jesseduffield/lazygit/pkg/commands/types/enums"
@@ -53,7 +54,7 @@ func (self *ModeHelper) Statuses() []ModeStatus {
 					fmt.Sprintf(
 						"%s %s",
 						self.c.Tr.LcShowingGitDiff,
-						"git diff "+self.diffHelper.DiffStr(),
+						"git diff "+strings.Join(self.diffHelper.DiffArgs(), " "),
 					),
 					style.FgMagenta,
 				)

pkg/gui/controllers/local_commits_controller.go

@@ -288,7 +288,7 @@ func (self *LocalCommitsController) doRewordEditor() error {
 	self.c.LogAction(self.c.Tr.Actions.RewordCommit)
 
 	if self.isHeadCommit() {
-		return self.c.RunSubprocessAndRefresh(self.c.OS().Cmd.New("git commit --allow-empty --amend --only"))
+		return self.c.RunSubprocessAndRefresh(self.c.Git().Commit.RewordLastCommitInEditorCmdObj())
 	}
 
 	subProcess, err := self.c.Git().Rebase.RewordCommitInEditor(