path/filepath: add test cases for walking a symlink-to-symlink-to-dir

The "double link with slash" test is skipped on darwin due to an
apparent kernel / libc bug. If the bug is present on other platforms
too, I'd like to know about it.

For #59586.

Change-Id: I4bdd6a80a3ed7b0960ea6da30f91a655f317d512
Reviewed-on: https://go-review.googlesource.com/c/go/+/484395
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index cfc5cad863abfc1a37a15d85ec202ac6e5cbab76..aed8cc8383f79e77fb82467383ca390d2749d6c0 100644 (file)
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -13,6 +13,7 @@ import (
        "path/filepath"
        "reflect"
        "runtime"
+       "slices"
        "sort"
        "strings"
        "syscall"
@@ -842,6 +843,16 @@ func TestWalkSymlinkRoot(t *testing.T) {
                t.Fatal(err)
        }
 
+       abslink := filepath.Join(td, "abslink")
+       if err := os.Symlink(dir, abslink); err != nil {
+               t.Fatal(err)
+       }
+
+       linklink := filepath.Join(td, "linklink")
+       if err := os.Symlink("link", linklink); err != nil {
+               t.Fatal(err)
+       }
+
        // Per https://pubs.opengroup.org/onlinepubs/9699919799.2013edition/basedefs/V1_chap04.html#tag_04_12:
        // “A pathname that contains at least one non- <slash> character and that ends
        // with one or more trailing <slash> characters shall not be resolved
@@ -854,9 +865,10 @@ func TestWalkSymlinkRoot(t *testing.T) {
        // but if it does end in a slash, Walk should walk the directory to which the symlink
        // refers (since it must be fully resolved before walking).
        for _, tt := range []struct {
-               desc string
-               root string
-               want []string
+               desc      string
+               root      string
+               want      []string
+               buggyGOOS []string
        }{
                {
                        desc: "no slash",
@@ -868,6 +880,27 @@ func TestWalkSymlinkRoot(t *testing.T) {
                        root: link + string(filepath.Separator),
                        want: []string{link, filepath.Join(link, "foo")},
                },
+               {
+                       desc: "abs no slash",
+                       root: abslink,
+                       want: []string{abslink},
+               },
+               {
+                       desc: "abs with slash",
+                       root: abslink + string(filepath.Separator),
+                       want: []string{abslink, filepath.Join(abslink, "foo")},
+               },
+               {
+                       desc: "double link no slash",
+                       root: linklink,
+                       want: []string{linklink},
+               },
+               {
+                       desc:      "double link with slash",
+                       root:      linklink + string(filepath.Separator),
+                       want:      []string{linklink, filepath.Join(linklink, "foo")},
+                       buggyGOOS: []string{"darwin"}, // https://go.dev/issue/59586
+               },
        } {
                tt := tt
                t.Run(tt.desc, func(t *testing.T) {
@@ -885,7 +918,12 @@ func TestWalkSymlinkRoot(t *testing.T) {
                        }
 
                        if !reflect.DeepEqual(walked, tt.want) {
-                               t.Errorf("Walk(%#q) visited %#q; want %#q", tt.root, walked, tt.want)
+                               t.Logf("Walk(%#q) visited %#q; want %#q", tt.root, walked, tt.want)
+                               if slices.Contains(tt.buggyGOOS, runtime.GOOS) {
+                                       t.Logf("(ignoring known bug on %v)", runtime.GOOS)
+                               } else {
+                                       t.Fail()
+                               }
                        }
                })
        }