pkg/aflow/action/kernel: add CheckoutScratch action

The action checks out a temp dir for code edits and patch testing.

Author: dvyukov

pkg/aflow/action/kernel/checkout.go

@@ -18,6 +18,11 @@ import (
 // outputs the source directory with the checkout.
 var Checkout = aflow.NewFuncAction("kernel-checkouter", checkout)
 
+// Checkout action checks out the Linux kernel on the given commit
+// in a private temp dir that lives only for the duration of the workflow.
+// It's supposed to be used for code edits.
+var CheckoutScratch = aflow.NewFuncAction("kernel-scratch-checkouter", checkoutScratch)
+
 type checkoutArgs struct {
 	KernelRepo   string
 	KernelCommit string
@@ -28,6 +33,15 @@ type checkoutResult struct {
 	KernelSrc string
 }
 
+type checkoutScratchArgs struct {
+	KernelSrc string
+}
+
+type checkoutScratchResult struct {
+	// Temp dir with the checked out sources.
+	KernelScratchSrc string
+}
+
 func checkout(ctx *aflow.Context, args checkoutArgs) (checkoutResult, error) {
 	var res checkoutResult
 	err := UseLinuxRepo(ctx, func(kernelRepoDir string, repo vcs.Repo) error {
@@ -58,24 +72,39 @@ func checkout(ctx *aflow.Context, args checkoutArgs) (checkoutResult, error) {
 					}
 				}
 			}
-			if _, err := osutil.RunCmd(time.Hour, dir, "git", "init"); err != nil {
-				return err
-			}
-			if _, err := osutil.RunCmd(time.Hour, dir, "git", "remote", "add", "origin", kernelRepoDir); err != nil {
-				return err
-			}
-			if _, err := osutil.RunCmd(time.Hour, dir, "git", "pull", "origin", "HEAD", "--depth=1",
-				"--allow-unrelated-histories"); err != nil {
-				return err
-			}
-			return nil
+			return shallowGitClone(dir, kernelRepoDir)
 		})
 		res.KernelSrc = dir
 		return err
 	})
 	return res, err
 }
 
+func checkoutScratch(ctx *aflow.Context, args checkoutScratchArgs) (checkoutScratchResult, error) {
+	dir, err := ctx.TempDir()
+	if err != nil {
+		return checkoutScratchResult{}, err
+	}
+	if err := shallowGitClone(dir, args.KernelSrc); err != nil {
+		return checkoutScratchResult{}, err
+	}
+	return checkoutScratchResult{dir}, nil
+}
+
+func shallowGitClone(dir, remoteDir string) error {
+	if _, err := osutil.RunCmd(time.Hour, dir, "git", "init"); err != nil {
+		return err
+	}
+	if _, err := osutil.RunCmd(time.Hour, dir, "git", "remote", "add", "origin", remoteDir); err != nil {
+		return err
+	}
+	if _, err := osutil.RunCmd(time.Hour, dir, "git", "pull", "origin", "HEAD", "--depth=1",
+		"--allow-unrelated-histories"); err != nil {
+		return err
+	}
+	return nil
+}
+
 var repoMu sync.Mutex
 
 func UseLinuxRepo(ctx *aflow.Context, fn func(string, vcs.Repo) error) error {

pkg/aflow/flow/patching/patching.go

@@ -36,6 +36,7 @@ type Inputs struct {
 type Outputs struct {
 	PatchDescription string
 	PatchDiff        string
+	KernelScratchSrc string // it's unused for now, but should be used by codeeditor tool later
 }
 
 func init() {
@@ -61,6 +62,7 @@ func init() {
 					Prompt:      debuggingPrompt,
 					Tools:       tools,
 				},
+				kernel.CheckoutScratch,
 				&aflow.LLMAgent{
 					Name:        "diff-generator",
 					Model:       aflow.BestExpensiveModel,