Fix language inference in generate.py

fairseq/data.py

@@ -18,30 +18,32 @@ from fairseq.indexed_dataset import IndexedDataset, IndexedInMemoryDataset
 
 
 def load_with_check(path, load_splits, src=None, dst=None):
-    """Loads the train, valid, and test sets from the specified folder
-    and check that training files exist."""
+    """Loads specified data splits (e.g., test, train or valid) from the
+    specified folder and check that files exist."""
 
     def find_language_pair(files):
+        for split in load_splits:
             for filename in files:
                 parts = filename.split('.')
-            if parts[0] == 'train' and parts[-1] == 'idx':
+                if parts[0] == split and parts[-1] == 'idx':
                     return parts[1].split('-')
 
-    def train_file_exists(src, dst):
-        filename = 'train.{0}-{1}.{0}.idx'.format(src, dst)
+    def split_exists(split, src, dst):
+        filename = '{0}.{1}-{2}.{1}.idx'.format(split, src, dst)
         return os.path.exists(os.path.join(path, filename))
 
     if src is None and dst is None:
         # find language pair automatically
         src, dst = find_language_pair(os.listdir(path))
-    elif train_file_exists(src, dst):
-        # check for src-dst langcode
-        pass
-    elif train_file_exists(dst, src):
-        # check for dst-src langcode
+
+    if not split_exists(load_splits[0], src, dst):
+        # try reversing src and dst
         src, dst = dst, src
-    else:
-        raise ValueError('training file not found for {}-{}'.format(src, dst))
+
+    for split in load_splits:
+        if not split_exists(load_splits[0], src, dst):
+            raise ValueError('Data split not found: {}-{} ({})'.format(
+                src, dst, split))
 
     dataset = load(path, load_splits, src, dst)
     return dataset