Retry on index.lock error

I don't know why we're getting index.lock errors but they're impossile to stop
anyway given that other processes can be calling git commands. So we're retrying
a few times before re-raising. To do this we need to clone the command and the current
implementation for that is best-effort.

I do worry about the maintainability of that but we'll see how it goes.

pkg/commands/git_cmd_obj_runner.go

@@ -1,6 +1,9 @@
 package commands
 
 import (
+	"strings"
+	"time"
+
 	"github.com/jesseduffield/lazygit/pkg/commands/oscommands"
 	"github.com/sirupsen/logrus"
 )
@@ -18,7 +21,26 @@ func (self *gitCmdObjRunner) Run(cmdObj oscommands.ICmdObj) error {
 }
 
 func (self *gitCmdObjRunner) RunWithOutput(cmdObj oscommands.ICmdObj) (string, error) {
-	return self.innerRunner.RunWithOutput(cmdObj)
+	// TODO: have this retry logic in other places we run the command
+	waitTime := 50 * time.Millisecond
+	retryCount := 5
+
+	var output string
+	var err error
+	for i := 0; i < retryCount; i++ {
+		newCmdObj := cmdObj.Clone()
+		output, err = self.innerRunner.RunWithOutput(newCmdObj)
+
+		if err == nil || !strings.Contains(output, ".git/index.lock") {
+			return output, err
+		}
+
+		// if we have an error based on the index lock, we should wait a bit and then retry
+		self.log.Warn("index.lock prevented command from running. Retrying command after a small wait")
+		time.Sleep(waitTime)
+	}
+
+	return output, err
 }
 
 func (self *gitCmdObjRunner) RunWithOutputs(cmdObj oscommands.ICmdObj) (string, string, error) {

pkg/commands/oscommands/cmd_obj.go

@@ -65,6 +65,8 @@ type ICmdObj interface {
 
 	GetCredentialStrategy() CredentialStrategy
 	GetTask() gocui.Task
+
+	Clone() ICmdObj
 }
 
 type CmdObj struct {
@@ -215,3 +217,21 @@ func (self *CmdObj) GetCredentialStrategy() CredentialStrategy {
 func (self *CmdObj) GetTask() gocui.Task {
 	return self.task
 }
+
+func (self *CmdObj) Clone() ICmdObj {
+	newCmdObj := &CmdObj{}
+	*newCmdObj = *self
+	newCmdObj.cmd = cloneCmd(self.cmd)
+	if self.task != nil {
+		// TODO: clone the task as well. We can't re-use tasks once they've been completed.
+		panic("Cannot clone a command object that has a task, not yet implemented")
+	}
+	return newCmdObj
+}
+
+func cloneCmd(cmd *exec.Cmd) *exec.Cmd {
+	clone := &exec.Cmd{}
+	*clone = *cmd
+
+	return clone
+}

pkg/integration/tests/file/discard_changes.go

@@ -8,7 +8,7 @@ import (
 var DiscardChanges = NewIntegrationTest(NewIntegrationTestArgs{
 	Description:  "Discarding all possible permutations of changed files",
 	ExtraCmdArgs: []string{},
-	Skip:         true, // failing due to index.lock file being created
+	Skip:         false,
 	SetupConfig: func(config *config.AppConfig) {
 	},
 	SetupRepo: func(shell *Shell) {