adjust path extracted from file: url on Windows (#416)

* adjust path extracted from file: url on Windows

Fixes #415

2 files changed, 57 insertions, 2 deletions

diff --git a/plumbing/transport/file/client.go b/plumbing/transport/file/client.go
index 38714e2..d921d0a 100644
--- a/plumbing/transport/file/client.go
+++ b/plumbing/transport/file/client.go
@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/go-git/go-git/v5/plumbing/transport"
@@ -95,7 +96,23 @@ func (r *runner) Command(cmd string, ep *transport.Endpoint, auth transport.Auth
 		}
 	}
 
-	return &command{cmd: execabs.Command(cmd, ep.Path)}, nil
+	return &command{cmd: execabs.Command(cmd, adjustPathForWindows(ep.Path))}, nil
+}
+
+func isDriveLetter(c byte) bool {
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
+}
+
+// On Windows, the path that results from a file: URL has a leading slash. This
+// has to be removed if there's a drive letter
+func adjustPathForWindows(p string) string {
+	if runtime.GOOS != "windows" {
+		return p
+	}
+	if len(p) >= 3 && p[0] == '/' && isDriveLetter(p[1]) && p[2] == ':' {
+		return p[1:]
+	}
+	return p
 }
 
 type command struct {
diff --git a/repository_windows_test.go b/repository_windows_test.go
index bec0acd..e7c1ac7 100644
--- a/repository_windows_test.go
+++ b/repository_windows_test.go
@@ -1,9 +1,47 @@
 package git
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+
+	"github.com/go-git/go-billy/v5/util"
+	"github.com/go-git/go-git/v5/storage/memory"
+	. "gopkg.in/check.v1"
+)
 
 // preReceiveHook returns the bytes of a pre-receive hook script
 // that prints m before exiting successfully
 func preReceiveHook(m string) []byte {
 	return []byte(fmt.Sprintf("#!C:/Program\\ Files/Git/usr/bin/sh.exe\nprintf '%s'\n", m))
 }
+
+func (s *RepositorySuite) TestCloneFileUrlWindows(c *C) {
+	dir, clean := s.TemporalDir()
+	defer clean()
+
+	r, err := PlainInit(dir, false)
+	c.Assert(err, IsNil)
+
+	err = util.WriteFile(r.wt, "foo", nil, 0755)
+	c.Assert(err, IsNil)
+
+	w, err := r.Worktree()
+	c.Assert(err, IsNil)
+
+	_, err = w.Add("foo")
+	c.Assert(err, IsNil)
+
+	_, err = w.Commit("foo", &CommitOptions{
+		Author:    defaultSignature(),
+		Committer: defaultSignature(),
+	})
+	c.Assert(err, IsNil)
+
+	url := "file:///" + strings.ReplaceAll(dir, "\\", "/")
+	c.Assert(url, Matches, "file:///[A-Za-z]:/.*")
+	_, err = Clone(memory.NewStorage(), nil, &CloneOptions{
+		URL: url,
+	})
+
+	c.Assert(err, IsNil)
+}