refactor: replace strutil.DedupeSlice with generic bkslices.Dedupe

Introduce util/bkslices.Dedupe[T] as a generic replacement
for the string-only strutil.DedupeSlice. Remove the now
unused util/strutil package.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

util/bkslices/dedupe.go

@@ -0,0 +1,15 @@
+package bkslices
+
+// Dedupe returns the input values in their original order without duplicates.
+func Dedupe[T comparable](in []T) []T {
+	seen := make(map[T]struct{}, len(in))
+	out := make([]T, 0, len(in))
+	for _, v := range in {
+		if _, ok := seen[v]; ok {
+			continue
+		}
+		seen[v] = struct{}{}
+		out = append(out, v)
+	}
+	return out
+}

util/rootless/mountopts/mountopts_linux.go

@@ -2,7 +2,7 @@ package mountopts
 
 import (
 	"github.com/containerd/containerd/v2/core/mount"
-	"github.com/moby/buildkit/util/strutil"
+	"github.com/moby/buildkit/util/bkslices"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
@@ -59,7 +59,7 @@ func FixUp(mounts []mount.Mount) ([]mount.Mount, error) {
 		if err != nil {
 			return nil, errors.Wrapf(err, "failed to get unprivileged mount flags for %+v", m)
 		}
-		m.Options = strutil.DedupeSlice(append(m.Options, unpriv...))
+		m.Options = bkslices.Dedupe(append(m.Options, unpriv...))
 		mounts[i] = m
 	}
 	return mounts, nil
@@ -81,7 +81,7 @@ func FixUpOCI(mounts []specs.Mount) ([]specs.Mount, error) {
 		if err != nil {
 			return nil, errors.Wrapf(err, "failed to get unprivileged mount flags for %+v", m)
 		}
-		m.Options = strutil.DedupeSlice(append(m.Options, unpriv...))
+		m.Options = bkslices.Dedupe(append(m.Options, unpriv...))
 		mounts[i] = m
 	}
 	return mounts, nil

util/strutil/strutil.go

@@ -1,30 +0,0 @@
-/*
-   Copyright The containerd Authors.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
-
-package strutil
-
-// DedupeSlice is from https://github.com/containerd/nerdctl/blob/v1.2.1/pkg/strutil/strutil.go#L72-L82
-func DedupeSlice(in []string) []string {
-	m := make(map[string]struct{})
-	var res []string
-	for _, s := range in {
-		if _, ok := m[s]; !ok {
-			res = append(res, s)
-			m[s] = struct{}{}
-		}
-	}
-	return res
-}