loader: find mixed-case loose RomFS directories consistently

Linux missed base version metadata for Base/RomFS while Windows included it. Use a case-insensitive fallback for the loose directory and check the version and resulting archive checksum.

Assisted by Codex.

2 files changed, 24 insertions, 3 deletions

diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index 4b1168a59b..49352a5b49 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -81,6 +81,24 @@ struct PatchCollection {
 
 namespace {
 
+FileSys::VirtualDir FindLooseRomFSDirectory(const FileSys::VirtualDir& parent) {
+    if (parent == nullptr) {
+        return nullptr;
+    }
+    if (const auto dir = parent->GetSubdirectory("romfs")) {
+        return dir;
+    }
+    for (const auto& dir : parent->GetSubdirectories()) {
+        const auto name = dir->GetName();
+        if (name.size() == 5 && std::equal(name.begin(), name.end(), "romfs", [](char a, char b) {
+                return std::tolower(static_cast<unsigned char>(a)) == b;
+            })) {
+            return dir;
+        }
+    }
+    return nullptr;
+}
+
 // RomFS for a loose ExeFS: the first .romfs file next to main, else a romfs/ directory next to
 // the exefs/ directory (the usual layout of an extracted title).
 FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
@@ -93,7 +111,7 @@ FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
         }
     }
     if (const auto parent = exefs_dir->GetParentDirectory()) {
-        if (const auto romfs_dir = parent->GetSubdirectory("romfs")) {
+        if (const auto romfs_dir = FindLooseRomFSDirectory(parent)) {
             // Building it walks every file and keeps an object for each (title 1: 206k files, ~150
             // MiB), so loaders of the same directory share one build while any of them holds it.
             static std::mutex cache_mutex;
@@ -268,7 +286,7 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(FileSys
 
     romfs_exefs_dir = file_dir;
     if (const auto title_dir = file_dir->GetParentDirectory()) {
-        romfs_version = RomFSProductVersion(title_dir->GetSubdirectory("romfs"));
+        romfs_version = RomFSProductVersion(FindLooseRomFSDirectory(title_dir));
     }
 }
 
diff --git a/src/tests/core/nup_writer.cpp b/src/tests/core/nup_writer.cpp
index c0230d8694..79a4015e2c 100644
--- a/src/tests/core/nup_writer.cpp
+++ b/src/tests/core/nup_writer.cpp
@@ -197,9 +197,11 @@ TEST_CASE("NUP packs base, updates and add-ons and reads back through NupContain
     REQUIRE(packages[0].kind == NupContainer::PackageKind::Base);
     REQUIRE(packages[0].title_id == TitleId);
     REQUIRE(packages[0].version == 0);
+    REQUIRE(packages[0].display_version == "1.0.0");
     REQUIRE(packages[0].npdm.size() == 0x100);
     REQUIRE(packages[1].kind == NupContainer::PackageKind::Update);
     REQUIRE(packages[1].version == 65536);
+    REQUIRE(packages[1].display_version == "1.1.0");
     REQUIRE(packages[1].title_id == TitleId);
     REQUIRE_FALSE(packages[1].standalone_update);
     REQUIRE(packages[2].kind == NupContainer::PackageKind::Update);
@@ -388,7 +390,8 @@ TEST_CASE("NUP output is reproducible", "[nup]") {
     for (const u8 b : Sha256(ReadAll(archive))) {
         hex += fmt::format("{:02x}", b);
     }
-    REQUIRE(hex == "df8446903ab2c39a51af0304935eb4aa5d8ead105440976ceae7ab97133f6143");
+    // The mixed-case Base/RomFS directory supplies base version 1.0.0 on every platform.
+    REQUIRE(hex == "718231e0974ca04c7be7bd6ed4334015b777c6e5f1ed51de23f899f81ee004ab");
 }
 
 TEST_CASE("NUP writes metadata overrides to the base and the newest update", "[nup]") {