NativeFileSystem with an absolute base path mounted at / resolves wrong virtual paths

[JanSimek]

After v2.1.1, FileInfo::Configure() strips aliasPath before basePath. Because
aliasPath is checked with fileName.find(aliasPath) == 0, a root alias of "/" matches every
absolute path (they all start with /). As a result, a NativeFileSystem created with an absolute
base path and mounted at alias "/" no longer strips the base path, so every file's VirtualPath()
becomes its full absolute path instead of the intended alias-relative path. Files can no longer be
opened by their virtual path.

See commit 487b922 in include/vfspp/FileInfo.hpp:

 void Configure(const std::string& aliasPath, const std::string& basePath, const std::string& fileName)
 {
-    // Remove alias path from file name if any
     std::string strippedFileName = fileName;
-    if (!basePath.empty() && fileName.find(basePath) == 0) {
+    if (!aliasPath.empty() && fileName.find(aliasPath) == 0) {
+        strippedFileName = fileName.substr(aliasPath.length());
+    } else if (!basePath.empty() && fileName.find(basePath) == 0) {
         strippedFileName = fileName.substr(basePath.length());
     }

Minimal reproduction

#include <vfspp/FileInfo.hpp>
#include <cassert>

int main()
{
    // alias "/", an ABSOLUTE base path, and a file discovered under it
    // (this is exactly what NativeFileSystem builds for each entry).
    vfspp::FileInfo info("/", "/home/user/game", "/home/user/game/data/maps/arvillag.map");

    // Expected: base path stripped, alias prepended.
    //   v2.1.1  -> "/data/maps/arvillag.map"                      (correct)
    //   master  -> "/home/user/game/data/maps/arvillag.map"      (base path NOT stripped)
    assert(info.VirtualPath() == "/data/maps/arvillag.map");
}

[nextgeniuspro]

Hi @JanSimek , added your fix to directories_support branch. Will merge it soon. Thank you!