Resolve native imports beneath nested roots

docs/roadmap/remediation.md

@@ -1,6 +1,6 @@
 # Import Discovery and Scheduling Review Findings
 
-Status: in progress; issues 1–2 complete, four findings remain.
+Status: in progress; issues 1–3 complete, three findings remain.
 
 Reviewed implementation: `aa93aed..15943e2`, ending at
 `15943e233ca3cd1286c03c0e7085871db344cd4b`, against the accepted
@@ -92,7 +92,7 @@ items, underlays, and selected main items, and failed before the change. The
 full everyday check passed, including existing default/enabled source-version
 and assigned-index ownership regressions.
 
-## 3. [ ] P2 — Accept valid multi-component native filesystem roots
+## 3. [x] P2 — Accept valid multi-component native filesystem roots
 
 Owner: [resolveNativeImportPath](../../internal/engine/filesystem_links.go),
 especially lines 170–181.
@@ -114,6 +114,12 @@ resolved targets. Test directory and glob discovery under multi-component roots,
 with ordinary entries and supported symlinks. Do not require consumers to flatten
 their roots or remove optional link-inspection capability.
 
+Completed: native link resolution allows ancestor prefixes while resolving a
+contained multi-component path; selected paths and resolved link targets still
+undergo their existing containment checks. Public directory/glob regressions
+cover ordinary and aliased roots plus escaping links. All four valid cases
+failed before the fix. The full everyday check passed.
+
 ## 4. [ ] P2 — Distinguish finite symlink reuse from actual cycles
 
 Owners: [resolveHostImportPath and resolveNativeImportPath](../../internal/engine/filesystem_links.go),

facade_import_root_test.go

@@ -0,0 +1,52 @@
+package configkit_test
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+func TestFacadeNativeDiscoveryWithNestedRoot(t *testing.T) {
+	root := t.TempDir()
+	parts := filepath.Join(root, "nested/root/parts")
+	if err := os.MkdirAll(parts, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(parts, "value.yml"), []byte("value: 1\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink("parts", filepath.Join(root, "nested/root/linked")); err != nil {
+		t.Skipf("symlinks unavailable: %v", err)
+	}
+	filesystem := configkit.NewFilesystem("nested", os.DirFS(root))
+	context := &configkit.FilesystemContext{FS: &filesystem, Root: "nested/root", BaseDir: "nested/root"}
+	for _, selector := range []string{
+		"dir: parts", "glob: 'parts/*.yml'", "dir: linked", "glob: 'lin*/*.yml'",
+	} {
+		t.Run(selector, func(t *testing.T) {
+			result, err := configkit.Load(configkit.Bytes("main", []byte("configkit:\n  imports:\n    - "+selector+"\n")), configkit.Options[map[string]any]{Imports: true, Filesystem: context})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if result.Config["value"] != int64(1) {
+				t.Fatalf("configuration = %#v", result.Config)
+			}
+		})
+	}
+	if err := os.WriteFile(filepath.Join(root, "nested/outside.yml"), []byte("value: outside\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink("../../outside.yml", filepath.Join(parts, "escape.yml")); err != nil {
+		t.Fatal(err)
+	}
+	for _, selector := range []string{"dir: parts", "glob: 'parts/*.yml'"} {
+		_, err := configkit.Load(configkit.Bytes("main", []byte("configkit:\n  imports:\n    - "+selector+"\n")), configkit.Options[map[string]any]{Imports: true, Filesystem: context})
+		var loadError *configkit.LoadError
+		if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != configkit.CodeImportOutsideRoot {
+			t.Fatalf("escaping %s: %v", selector, err)
+		}
+	}
+}

internal/engine/filesystem_links.go

@@ -177,7 +177,9 @@ func resolveNativeImportPath(access *filesystemAccess, filesystem fs.ReadLinkFS,
 		if candidate == "" {
 			candidate = "."
 		}
-		if !access.contains(candidate) {
+		// Ancestors of a multi-component root are resolution prefixes, not
+		// selected targets. Complete paths and link targets remain contained.
+		if !access.contains(candidate) && !strings.HasPrefix(access.rootPath, candidate+"/") {
 			return "", errImportPathOutsideRoot
 		}
 		info, err := filesystem.Lstat(candidate)