virtfs: inline tree options, remove newTree/with* indirection

The with* functional options and newTree constructor were private and
only used in two places (builder and tests). Replaced with direct
field assignment on &Tree{} literals. Less abstraction, same behavior.

virtfs/builder.go

@@ -81,29 +81,28 @@ func build(d *FsNodeDecl, parentUid, parentGid string) *Tree {
 			mode = 0755
 		}
 
-		t := newTree(nil, mode,
-			withLister(func(_ []string) ([]os.DirEntry, error) {
+		t := &Tree{perm: mode}
+		t.listFn = func(_ []string) ([]os.DirEntry, error) {
 			return listDir(d, uid, gid)
-			}),
-			withReaddir(func(_ []string, name string) ([]os.DirEntry, error) {
+		}
+		t.readdirFn = func(_ []string, name string) ([]os.DirEntry, error) {
 			return readdirDir(d, uid, gid, name)
-			}),
-			withStat(func(_ []string, name string) (os.FileInfo, error) {
+		}
+		t.statFn = func(_ []string, name string) (os.FileInfo, error) {
 			return statDir(d, uid, gid, name)
-			}),
-			withOpener(func(_ []string, name string) (File, error) {
+		}
+		t.openFn = func(_ []string, name string) (File, error) {
 			return openDir(d, uid, gid, name)
-			}),
-			withDeleter(func(_ []string, name string) error {
+		}
+		t.deleteFn = func(_ []string, name string) error {
 			return deleteDir(d, name)
-			}),
-			withCreator(func(_ []string, name string, _ os.FileMode) error {
+		}
+		t.createFn = func(_ []string, name string, _ os.FileMode) error {
 			return fmt.Errorf("create not supported")
-			}),
-			withRenamer(func(_ []string, old, new string) error {
+		}
+		t.renameFn = func(_ []string, old, new string) error {
 			return renameDir(d, old, new)
-			}),
-		)
+		}
 		return t
 	}
 
@@ -111,14 +110,14 @@ func build(d *FsNodeDecl, parentUid, parentGid string) *Tree {
 	if mode == 0 {
 		mode = 0444
 	}
-	return newTree(nil, 0,
-		withLister(func(_ []string) ([]os.DirEntry, error) {
+	t := &Tree{}
+	t.listFn = func(_ []string) ([]os.DirEntry, error) {
 		return nil, fmt.Errorf("%s: is a file", d.Name)
-		}),
-		withOpener(func(_ []string, name string) (File, error) {
+	}
+	t.openFn = func(_ []string, name string) (File, error) {
 		return openLeaf(d, uid, gid, mode, name)
-		}),
-	)
+	}
+	return t
 }
 
 // ── directory ops ────────────────────────────────────────────────

virtfs/decl_test.go

@@ -85,12 +85,11 @@ func TestNodeOptions(t *testing.T) {
 // ══════════════════════════════════════════════════════════════════
 
 func TestTreeMount(t *testing.T) {
-	parent := newTree(nil, 0755)
-	child := newTree(nil, 0755,
-		withLister(func(_ []string) ([]os.DirEntry, error) {
+	parent := &Tree{perm: 0755}
+	child := &Tree{perm: 0755}
+	child.listFn = func(_ []string) ([]os.DirEntry, error) {
 		return []os.DirEntry{fileEntry("childfile", 0444)}, nil
-		}),
-	)
+	}
 
 	parent.Mount("subdir", child)
 
@@ -111,8 +110,8 @@ func TestTreeMount(t *testing.T) {
 }
 
 func TestTreeSplit(t *testing.T) {
-	parent := newTree(nil, 0755)
-	child := newTree(nil, 0755)
+	parent := &Tree{perm: 0755}
+	child := &Tree{perm: 0755}
 	parent.Mount("sub", child)
 
 	c, rest, ok := parent.split("sub")

virtfs/tree.go

@@ -33,54 +33,6 @@ type Tree struct {
 	Data      any // user-attached state
 }
 
-// treeOption configures a Tree.
-type treeOption func(*Tree)
-
-// withLister overrides how the tree lists its entries.
-func withLister(fn func(dirs []string) ([]os.DirEntry, error)) treeOption {
-	return func(d *Tree) { d.listFn = fn }
-}
-
-// withCreator overrides file creation logic.
-func withCreator(fn func(dirs []string, name string, perm os.FileMode) error) treeOption {
-	return func(d *Tree) { d.createFn = fn }
-}
-
-// withDeleter overrides file deletion logic.
-func withDeleter(fn func(dirs []string, name string) error) treeOption {
-	return func(d *Tree) { d.deleteFn = fn }
-}
-
-// withRenamer overrides rename logic.
-func withRenamer(fn func(dirs []string, old, new string) error) treeOption {
-	return func(d *Tree) { d.renameFn = fn }
-}
-
-// withOpener overrides how entries are opened.
-func withOpener(fn func(dirs []string, name string) (File, error)) treeOption {
-	return func(d *Tree) { d.openFn = fn }
-}
-
-// withStat overrides how entries are stat'd.
-func withStat(fn func(dirs []string, name string) (os.FileInfo, error)) treeOption {
-	return func(d *Tree) { d.statFn = fn }
-}
-
-// withReaddir overrides subdirectory listing.
-func withReaddir(fn func(dirs []string, name string) ([]os.DirEntry, error)) treeOption {
-	return func(d *Tree) { d.readdirFn = fn }
-}
-
-// newTree creates a Tree. In EDSL usage, dirs is nil and all behavior
-// is provided via options.
-func newTree(dirs []string, perm os.FileMode, opts ...treeOption) *Tree {
-	d := &Tree{Tree: dirs, perm: perm}
-	for _, o := range opts {
-		o(d)
-	}
-	return d
-}
-
 // Mount attaches a child Tree at the given name.
 func (d *Tree) Mount(name string, child *Tree) {
 	if d.children == nil {

virtfs/tree_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestTreeMkdirAll(t *testing.T) {
 	tmpDir := t.TempDir()
-	tree := newTree([]string{tmpDir}, 0755)
+	tree := &Tree{Tree: []string{tmpDir}, perm: 0755}
 
 	err := tree.MkdirAll("a/b/c")
 	if err != nil {
@@ -25,7 +25,7 @@ func TestTreeMkdirAll(t *testing.T) {
 }
 
 func TestTreeMkdirAllNoBackingDir(t *testing.T) {
-	tree := newTree(nil, 0755)
+	tree := &Tree{perm: 0755}
 	err := tree.MkdirAll("somedir")
 	if err == nil {
 		t.Fatal("expected error for nil backing dir")
@@ -34,12 +34,11 @@ func TestTreeMkdirAllNoBackingDir(t *testing.T) {
 
 func TestTreeWithCustomFunctions(t *testing.T) {
 	listed := false
-	tree := newTree(nil, 0755,
-		withLister(func(_ []string) ([]os.DirEntry, error) {
+	tree := &Tree{perm: 0755}
+	tree.listFn = func(_ []string) ([]os.DirEntry, error) {
 		listed = true
 		return []os.DirEntry{fileEntry("a", 0644)}, nil
-		}),
-	)
+	}
 	entries, err := tree.List()
 	if err != nil {
 		t.Fatalf("List: %v", err)
@@ -53,16 +52,15 @@ func TestTreeWithCustomFunctions(t *testing.T) {
 }
 
 func TestTreeOpen(t *testing.T) {
-	tree := newTree(nil, 0644,
-		withOpener(func(_ []string, name string) (File, error) {
+	tree := &Tree{perm: 0644}
+	tree.openFn = func(_ []string, name string) (File, error) {
 		return &fileConfig{
 			StatFn:         func() (os.FileInfo, error) { return &SyntheticFileInfo{Name_: name}, nil },
 			ReadFn:         func() ([]byte, error) { return []byte("content"), nil },
 			WriteFn:        func([]byte) error { return nil },
 			BlockingReadFn: func(context.Context, string) ([]byte, string, error) { return nil, "", nil },
 		}, nil
-		}),
-	)
+	}
 	f, err := tree.Open("test")
 	if err != nil {
 		t.Fatalf("Open: %v", err)
@@ -77,7 +75,7 @@ func TestTreeOpen(t *testing.T) {
 }
 
 func TestTreeOpenNotFound(t *testing.T) {
-	tree := newTree(nil, 0644)
+	tree := &Tree{perm: 0644}
 	_, err := tree.Open("nonexistent")
 	if err == nil {
 		t.Fatal("expected error")
@@ -85,11 +83,10 @@ func TestTreeOpenNotFound(t *testing.T) {
 }
 
 func TestTreeStat(t *testing.T) {
-	tree := newTree(nil, 0755,
-		withStat(func(_ []string, name string) (os.FileInfo, error) {
+	tree := &Tree{perm: 0755}
+	tree.statFn = func(_ []string, name string) (os.FileInfo, error) {
 		return &SyntheticFileInfo{Name_: name, Mode_: 0644, Size_: 42}, nil
-		}),
-	)
+	}
 	fi, err := tree.Stat("hello")
 	if err != nil {
 		t.Fatalf("Stat: %v", err)
@@ -100,8 +97,8 @@ func TestTreeStat(t *testing.T) {
 }
 
 func TestTreeStatOpenerFallback(t *testing.T) {
-	tree := newTree(nil, 0755,
-		withOpener(func(_ []string, name string) (File, error) {
+	tree := &Tree{perm: 0755}
+	tree.openFn = func(_ []string, name string) (File, error) {
 		return &fileConfig{
 			StatFn: func() (os.FileInfo, error) {
 				return &SyntheticFileInfo{Name_: name, Size_: 99}, nil
@@ -110,8 +107,7 @@ func TestTreeStatOpenerFallback(t *testing.T) {
 			WriteFn:        func([]byte) error { return nil },
 			BlockingReadFn: func(context.Context, string) ([]byte, string, error) { return nil, "", nil },
 		}, nil
-		}),
-	)
+	}
 	fi, err := tree.Stat("x")
 	if err != nil {
 		t.Fatalf("Stat: %v", err)
@@ -122,21 +118,20 @@ func TestTreeStatOpenerFallback(t *testing.T) {
 }
 
 func TestTreeChildDelegation(t *testing.T) {
-	child := newTree(nil, 0755,
-		withOpener(func(_ []string, name string) (File, error) {
+	child := &Tree{perm: 0755}
+	child.openFn = func(_ []string, name string) (File, error) {
 		return &fileConfig{
 			StatFn:         func() (os.FileInfo, error) { return &SyntheticFileInfo{Name_: name}, nil },
 			ReadFn:         func() ([]byte, error) { return []byte("child:" + name), nil },
 			WriteFn:        func([]byte) error { return nil },
 			BlockingReadFn: func(context.Context, string) ([]byte, string, error) { return nil, "", nil },
 		}, nil
-		}),
-		withLister(func(_ []string) ([]os.DirEntry, error) {
+	}
+	child.listFn = func(_ []string) ([]os.DirEntry, error) {
 		return []os.DirEntry{fileEntry("inner", 0644)}, nil
-		}),
-	)
+	}
 
-	parent := newTree(nil, 0755)
+	parent := &Tree{perm: 0755}
 	parent.Mount("sub", child)
 
 	// Open delegated to child
@@ -176,8 +171,8 @@ func TestTreeChildDelegation(t *testing.T) {
 
 func TestTreeChildMkdirAll(t *testing.T) {
 	tmpDir := t.TempDir()
-	child := newTree([]string{tmpDir}, 0755)
-	parent := newTree(nil, 0755)
+	child := &Tree{Tree: []string{tmpDir}, perm: 0755}
+	parent := &Tree{perm: 0755}
 	parent.Mount("sub", child)
 
 	err := parent.MkdirAll("sub/new/deep/path")
@@ -192,12 +187,11 @@ func TestTreeChildMkdirAll(t *testing.T) {
 
 func TestTreeCreate(t *testing.T) {
 	created := ""
-	tree := newTree(nil, 0644,
-		withCreator(func(_ []string, name string, _ os.FileMode) error {
+	tree := &Tree{perm: 0644}
+	tree.createFn = func(_ []string, name string, _ os.FileMode) error {
 		created = name
 		return nil
-		}),
-	)
+	}
 	if err := tree.Create("newfile"); err != nil {
 		t.Fatalf("Create: %v", err)
 	}
@@ -208,12 +202,11 @@ func TestTreeCreate(t *testing.T) {
 
 func TestTreeDelete(t *testing.T) {
 	deleted := ""
-	tree := newTree(nil, 0644,
-		withDeleter(func(_ []string, name string) error {
+	tree := &Tree{perm: 0644}
+	tree.deleteFn = func(_ []string, name string) error {
 		deleted = name
 		return nil
-		}),
-	)
+	}
 	if err := tree.Delete("old"); err != nil {
 		t.Fatalf("Delete: %v", err)
 	}
@@ -224,12 +217,11 @@ func TestTreeDelete(t *testing.T) {
 
 func TestTreeRename(t *testing.T) {
 	var oldN, newN string
-	tree := newTree(nil, 0644,
-		withRenamer(func(_ []string, old, new string) error {
+	tree := &Tree{perm: 0644}
+	tree.renameFn = func(_ []string, old, new string) error {
 		oldN, newN = old, new
 		return nil
-		}),
-	)
+	}
 	if err := tree.Rename("a", "b"); err != nil {
 		t.Fatalf("Rename: %v", err)
 	}
@@ -239,11 +231,10 @@ func TestTreeRename(t *testing.T) {
 }
 
 func TestTreeReaddir(t *testing.T) {
-	tree := newTree(nil, 0755,
-		withReaddir(func(_ []string, name string) ([]os.DirEntry, error) {
+	tree := &Tree{perm: 0755}
+	tree.readdirFn = func(_ []string, name string) ([]os.DirEntry, error) {
 		return []os.DirEntry{fileEntry("child", 0644)}, nil
-		}),
-	)
+	}
 	entries, err := tree.Readdir("subdir")
 	if err != nil {
 		t.Fatalf("Readdir: %v", err)
@@ -254,7 +245,7 @@ func TestTreeReaddir(t *testing.T) {
 }
 
 func TestReaddirNotFound(t *testing.T) {
-	tree := newTree(nil, 0755)
+	tree := &Tree{perm: 0755}
 	_, err := tree.Readdir("nowhere")
 	if err == nil {
 		t.Fatal("expected error")