ensure all fast5s are removed from mixed dataset

dorado/data_loader/DataLoader.cpp

@@ -102,6 +102,50 @@ std::string get_string_attribute(const HighFive::Group& group, const std::string
     }
     return attribute_string;
 }
+
+std::vector<std::filesystem::directory_entry> filter_fast5_for_mixed_datasets(
+        const std::vector<std::filesystem::directory_entry>& files) {
+    std::vector<std::filesystem::directory_entry> pod5_entries;
+    std::vector<std::filesystem::directory_entry> fast5_entries;
+
+    bool issued_fast5_warn = false;
+
+    for (const auto& entry : files) {
+        auto entry_path = std::filesystem::path(entry);
+        std::string ext = entry_path.extension().string();
+        std::transform(ext.begin(), ext.end(), ext.begin(),
+                       [](unsigned char c) { return std::tolower(c); });
+        if (ext == ".fast5") {
+            if (!issued_fast5_warn) {
+                spdlog::warn(
+                        "FAST5 support is unoptimized and will result in poor performance. "
+                        "Please convert your dataset to POD5: "
+                        "https://pod5-file-format.readthedocs.io/en/latest/docs/"
+                        "tools.html#pod5-convert-fast5");
+                issued_fast5_warn = true;
+            }
+
+            fast5_entries.push_back(entry);
+        } else if (ext == ".pod5") {
+            pod5_entries.push_back(entry);
+        }
+    }
+
+    if (pod5_entries.empty()) {
+        return fast5_entries;
+    } else if (!pod5_entries.empty() && !fast5_entries.empty()) {
+        for (const auto& f5 : fast5_entries) {
+            spdlog::warn(
+                    "Data folder contains both POD5 and FAST5 files. Please basecall "
+                    "FAST5 separately. Skipping FAST5 "
+                    "file from {}.",
+                    f5.path().string());
+        }
+    }
+
+    return pod5_entries;
+}
+
 }  // namespace
 
 namespace dorado {
@@ -295,35 +339,16 @@ void DataLoader::load_reads(const std::string& path,
             break;
         case ReadOrder::UNRESTRICTED:
             for (const auto& entry : iterator) {
-                static bool issued_fast5_warn = false;
-                static bool pod5_seen = false;
                 if (m_loaded_read_count == m_max_reads) {
                     break;
                 }
                 std::string ext = std::filesystem::path(entry).extension().string();
                 std::transform(ext.begin(), ext.end(), ext.begin(),
                                [](unsigned char c) { return std::tolower(c); });
                 if (ext == ".fast5") {
-                    if (!issued_fast5_warn) {
-                        spdlog::warn(
-                                "FAST5 support is unoptimized and will result in poor performance. "
-                                "Please convert your dataset to POD5: "
-                                "https://pod5-file-format.readthedocs.io/en/latest/docs/"
-                                "tools.html#pod5-convert-fast5");
-                        issued_fast5_warn = true;
-                    }
-                    if (pod5_seen) {
-                        spdlog::warn(
-                                "Data folder contains both POD5 and FAST5 files. Please basecall "
-                                "FAST5 separately. Skipping FAST5 "
-                                "file from {}.",
-                                entry.path().string());
-                    } else {
-                        load_fast5_reads_from_file(entry.path().string());
-                    }
+                    load_fast5_reads_from_file(entry.path().string());
                 } else if (ext == ".pod5") {
                     load_pod5_reads_from_file(entry.path().string());
-                    pod5_seen = true;
                 }
             }
             break;
@@ -333,7 +358,9 @@ void DataLoader::load_reads(const std::string& path,
         }
     };
 
-    iterate_directory(fetch_directory_entries(path, recursive_file_loading));
+    auto filtered_entries =
+            filter_fast5_for_mixed_datasets(fetch_directory_entries(path, recursive_file_loading));
+    iterate_directory(filtered_entries);
 }
 
 int DataLoader::get_num_reads(std::string data_path,