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/commands/oscommands/cmd_obj.go

@@ -2,7 +2,9 @@ package oscommands
 
 import (
 	"os/exec"
+	"strings"
 
+	"github.com/samber/lo"
 	"github.com/sasha-s/go-deadlock"
 )
 
@@ -15,6 +17,9 @@ type ICmdObj interface {
 	// into a terminal e.g. 'sh -c git commit' as opposed to 'sh -c "git commit"'
 	ToString() string
 
+	// outputs args vector e.g. ["git", "commit", "-m", "my message"]
+	Args() []string
+
 	AddEnvVars(...string) ICmdObj
 	GetEnvVars() []string
 
@@ -61,8 +66,11 @@ type ICmdObj interface {
 }
 
 type CmdObj struct {
-	cmdStr string
-	cmd    *exec.Cmd
+	// the secureexec package will swap out the first arg with the full path to the binary,
+	// so we store these args separately so that ToString() will output the original
+	args []string
+
+	cmd *exec.Cmd
 
 	runner ICmdObjRunner
 
@@ -104,7 +112,19 @@ func (self *CmdObj) GetCmd() *exec.Cmd {
 }
 
 func (self *CmdObj) ToString() string {
-	return self.cmdStr
+	// if a given arg contains a space, we need to wrap it in quotes
+	quotedArgs := lo.Map(self.args, func(arg string, _ int) string {
+		if strings.Contains(arg, " ") {
+			return `"` + arg + `"`
+		}
+		return arg
+	})
+
+	return strings.Join(quotedArgs, " ")
+}
+
+func (self *CmdObj) Args() []string {
+	return self.args
 }
 
 func (self *CmdObj) AddEnvVars(vars ...string) ICmdObj {