fix: keep the drive letter prefix in the path for windows

Signed-off-by: Alex Rohozneanu <[email protected]>

loader/loader.go

@@ -12,6 +12,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -575,11 +576,26 @@ func Dirs(paths []string) []string {
 // SplitPrefix returns a tuple specifying the document prefix and the file
 // path.
 func SplitPrefix(path string) ([]string, string) {
-	// Non-prefixed URLs can be returned without modification and their contents
-	// can be rooted directly under data.
-	if strings.Index(path, "://") == strings.Index(path, ":") {
+	pathRegex := "^(?:[a-zA-Z]:[^:]+|file:///.+|[^:]+|https?://[^\\s]+)$"
+
+	// Matches:
+
+	// Strings like "foo/bar" that do not contain a colon at all, linux/macOS style paths.
+	// Windows-style paths like "c:a/b/c" where the colon is after a single letter (indicating a drive).
+	// URLs like "file:///a/b/c" and "file:///c:/a/b/c".
+	// HTTP or HTTPS urls like "http://openpolicyagent.org
+
+	// Rejects:
+
+	// Strings like "foo:/bar", "foo.bar:/baz" where there is a non-drive prefix before a colon.
+	// Strings like "x.y:file:///a/b/c" where there is a prefix with dots and a colon before a valid URL.
+
+	match, err := regexp.MatchString(pathRegex, path)
+
+	if match && err == nil {
 		return nil, path
 	}
+
 	parts := strings.SplitN(path, ":", 2)
 	if len(parts) == 2 && len(parts[0]) > 0 {
 		return strings.Split(parts[0], "."), parts[1]

loader/loader_test.go

@@ -857,6 +857,10 @@ func TestSplitPrefix(t *testing.T) {
 			wantParts: []string{"foo"},
 			wantPath:  "/bar",
 		},
+		{
+			input:    "c:/a/b/c",
+			wantPath: "c:/a/b/c",
+		},
 		{
 			input:     "foo.bar:/baz",
 			wantParts: []string{"foo", "bar"},