build: resolve 8.3 filename format to long one on Windows

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

build/git.go

@@ -46,9 +46,9 @@ func getGitAttributes(ctx context.Context, contextPath string, dockerfilePath st
 	if filepath.IsAbs(contextPath) {
 		wd = contextPath
 	} else {
-		cwd, _ := os.Getwd()
-		wd, _ = filepath.Abs(filepath.Join(cwd, contextPath))
+		wd, _ = filepath.Abs(filepath.Join(getWd(), contextPath))
 	}
+	wd = gitutil.SanitizePath(wd)
 
 	gitc, err := gitutil.New(gitutil.WithContext(ctx), gitutil.WithWorkingDir(wd))
 	if err != nil {
@@ -104,8 +104,7 @@ func getGitAttributes(ctx context.Context, contextPath string, dockerfilePath st
 			dockerfilePath = filepath.Join(wd, "Dockerfile")
 		}
 		if !filepath.IsAbs(dockerfilePath) {
-			cwd, _ := os.Getwd()
-			dockerfilePath = filepath.Join(cwd, dockerfilePath)
+			dockerfilePath = filepath.Join(getWd(), dockerfilePath)
 		}
 		if r, err := filepath.Rel(root, dockerfilePath); err == nil && !strings.HasPrefix(r, "..") {
 			res["label:"+DockerfileLabel] = r
@@ -125,9 +124,21 @@ func getGitAttributes(ctx context.Context, contextPath string, dockerfilePath st
 			if err != nil {
 				continue
 			}
+			if lp, err := getLongPathName(dir); err == nil {
+				dir = lp
+			}
+			dir = gitutil.SanitizePath(dir)
 			if r, err := filepath.Rel(root, dir); err == nil && !strings.HasPrefix(r, "..") {
 				so.FrontendAttrs["vcs:localdir:"+k] = r
 			}
 		}
 	}, nil
 }
+
+func getWd() string {
+	wd, _ := os.Getwd()
+	if lp, err := getLongPathName(wd); err == nil {
+		return lp
+	}
+	return wd
+}

build/git_unix.go

@@ -0,0 +1,9 @@
+//go:build !windows
+// +build !windows
+
+package build
+
+// getLongPathName is a no-op on non-Windows platforms.
+func getLongPathName(path string) (string, error) {
+	return path, nil
+}

build/git_windows.go

@@ -0,0 +1,26 @@
+package build
+
+import "golang.org/x/sys/windows"
+
+// getLongPathName converts Windows short pathnames to full pathnames.
+// For example C:\Users\ADMIN~1 --> C:\Users\Administrator.
+func getLongPathName(path string) (string, error) {
+	// See https://groups.google.com/forum/#!topic/golang-dev/1tufzkruoTg
+	p, err := windows.UTF16FromString(path)
+	if err != nil {
+		return "", err
+	}
+	b := p // GetLongPathName says we can reuse buffer
+	n, err := windows.GetLongPathName(&p[0], &b[0], uint32(len(b)))
+	if err != nil {
+		return "", err
+	}
+	if n > uint32(len(b)) {
+		b = make([]uint16, n)
+		_, err = windows.GetLongPathName(&p[0], &b[0], uint32(len(b)))
+		if err != nil {
+			return "", err
+		}
+	}
+	return windows.UTF16ToString(b), nil
+}