chore: apply changes from code review

internal/deb/extract.go

@@ -266,8 +266,6 @@ func extractData(pkgReader io.ReadSeeker, options *ExtractOptions) error {
 			}
 			// Create the entry itself.
 			link := tarHeader.Linkname
-			// TODO: The first hard link in the tarball does not have tar.TypeLink flag.
-			// We need to update its fstutil.Entry.Link later.
 			if tarHeader.Typeflag == tar.TypeLink {
 				// A hard link requires the real path of the target file.
 				link = filepath.Join(options.TargetDir, link)

internal/slicer/slicer.go

@@ -32,9 +32,9 @@ type RunOptions struct {
 }
 
 type pathData struct {
-	until      setup.PathUntil
-	mutable    bool
-	isHardLink bool
+	until    setup.PathUntil
+	mutable  bool
+	hardLink bool
 }
 
 type contentChecker struct {
@@ -44,7 +44,8 @@ type contentChecker struct {
 func (cc *contentChecker) checkMutable(path string) error {
 	if !cc.knownPaths[path].mutable {
 		return fmt.Errorf("cannot write file which is not mutable: %s", path)
-	} else if cc.knownPaths[path].isHardLink { // mutable
+	}
+	if cc.knownPaths[path].hardLink {
 		return fmt.Errorf("cannot mutate a hard link: %s", path)
 	}
 	return nil
@@ -209,9 +210,9 @@ func Run(options *RunOptions) error {
 
 		if inSliceContents {
 			data := pathData{
-				mutable:    mutable,
-				until:      until,
-				isHardLink: entry.Mode.IsRegular() && entry.Link != "",
+				mutable:  mutable,
+				until:    until,
+				hardLink: entry.LinkType == fsutil.TypeHardLink,
 			}
 			addKnownPath(knownPaths, relPath, data)
 		}

internal/slicer/slicer_test.go

@@ -1764,7 +1764,7 @@ var slicerTests = []slicerTest{{
 	},
 	error: `slice test-package_myslice: cannot mutate a hard link: /hardlink`,
 }, {
-	summary: "Specifying mutability true for a hard link but not write to it is allowed",
+	summary: "Hard links can be marked as mutable, but not mutated",
 	slices: []setup.SliceKey{
 		{"test-package", "myslice"}},
 	pkgs: []*testutil.TestPackage{{