path/filepath: do not remove prefix "." when following path contains ":".

Fixes #52476

Change-Id: I9eb72ac7dbccd6322d060291f31831dc389eb9bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/401595
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/path/filepath/path.go b/src/path/filepath/path.go
index ec9e6d8a1f8616d00f7ca38bf868d54e726507fa..de7a2c758b1cf5d8e1c0b66db90b69c4f0492f2c 100644 (file)
--- a/src/path/filepath/path.go
+++ b/src/path/filepath/path.go
@@ -117,9 +117,21 @@ func Clean(path string) string {
                case os.IsPathSeparator(path[r]):
                        // empty path element
                        r++
-               case path[r] == '.' && (r+1 == n || os.IsPathSeparator(path[r+1])):
+               case path[r] == '.' && r+1 == n:
                        // . element
                        r++
+               case path[r] == '.' && os.IsPathSeparator(path[r+1]):
+                       // ./ element
+                       r++
+
+                       for r < len(path) && os.IsPathSeparator(path[r]) {
+                               r++
+                       }
+                       if out.w == 0 && volumeNameLen(path[r:]) > 0 {
+                               // When joining prefix "." and an absolute path on Windows,
+                               // the prefix should not be removed.
+                               out.append('.')
+                       }
                case path[r] == '.' && path[r+1] == '.' && (r+2 == n || os.IsPathSeparator(path[r+2])):
                        // .. element: remove to last separator
                        r += 2

diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index 1456ea737a1efa7d6b14f4682e5e18a3451896a5..a783d6be2838ab7321941bb71958bbe403b253b0 100644 (file)
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -93,6 +93,9 @@ var wincleantests = []PathTest{
        {`//host/share/foo/../baz`, `\\host\share\baz`},
        {`\\a\b\..\c`, `\\a\b\c`},
        {`\\a\b`, `\\a\b`},
+       {`.\c:`, `.\c:`},
+       {`.\c:\foo`, `.\c:\foo`},
+       {`.\c:foo`, `.\c:foo`},
 }
 
 func TestClean(t *testing.T) {

diff --git a/src/path/filepath/path_windows_test.go b/src/path/filepath/path_windows_test.go
index 37019210fa0346f8dc6b48abf3166d43e442b3e0..9e6c0ec81d901c147f549d1f458ac63c0ff13523 100644 (file)
--- a/src/path/filepath/path_windows_test.go
+++ b/src/path/filepath/path_windows_test.go
@@ -534,3 +534,29 @@ func TestNTNamespaceSymlink(t *testing.T) {
                t.Errorf(`EvalSymlinks(%q): got %q, want %q`, filelink, got, want)
        }
 }
+
+func TestIssue52476(t *testing.T) {
+       tests := []struct {
+               lhs, rhs string
+               want     string
+       }{
+               {`..\.`, `C:`, `..\C:`},
+               {`..`, `C:`, `..\C:`},
+               {`.`, `:`, `:`},
+               {`.`, `C:`, `.\C:`},
+               {`.`, `C:/a/b/../c`, `.\C:\a\c`},
+               {`.`, `\C:`, `.\C:`},
+               {`C:\`, `.`, `C:\`},
+               {`C:\`, `C:\`, `C:\C:`},
+               {`C`, `:`, `C\:`},
+               {`\.`, `C:`, `\C:`},
+               {`\`, `C:`, `\C:`},
+       }
+
+       for _, test := range tests {
+               got := filepath.Join(test.lhs, test.rhs)
+               if got != test.want {
+                       t.Errorf(`Join(%q, %q): got %q, want %q`, test.lhs, test.rhs, got, test.want)
+               }
+       }
+}