allow for "opening" an empty config from file

gp2040ce_bintools/storage.py

@@ -89,17 +89,24 @@ def get_config_footer(content: bytes) -> tuple[int, int, str]:
     return config_size, config_crc, config_magic
 
 
-def get_config_from_file(filename: str, whole_board: bool = False) -> Message:
+def get_config_from_file(filename: str, whole_board: bool = False, allow_no_file: bool = False) -> Message:
     """Read the specified file (memory dump or whole board dump) and get back its config section.
 
     Args:
         filename: the filename of the file to open and read
         whole_board: optional, if true, attempt to find the storage section from its normal location on a board
+        allow_no_file: if true, attempting to open a nonexistent file returns an empty config, else it errors
     Returns:
         the parsed configuration
     """
-    with open(filename, 'rb') as dump:
-        content = dump.read()
+    try:
+        with open(filename, 'rb') as dump:
+            content = dump.read()
+    except FileNotFoundError:
+        if not allow_no_file:
+            raise
+        config_pb2 = get_config_pb2()
+        return config_pb2.Config()
 
     if whole_board:
         return get_config(get_storage_section(content))

tests/test_storage.py

@@ -89,6 +89,21 @@ def test_get_config_from_file_whole_board_dump():
     assert config.addonOptions.bootselButtonOptions.enabled is False
 
 
+@with_pb2s
+def test_get_config_from_file_file_not_fonud_ok():
+    """If we allow opening a file that doesn't exist (e.g. for the editor), check we get an empty config."""
+    filename = os.path.join(HERE, 'test-files', 'nope.bin')
+    config = storage.get_config_from_file(filename, allow_no_file=True)
+    assert config.boardVersion == ''
+
+
+def test_get_config_from_file_file_not_fonud_raise():
+    """If we don't allow opening a file that doesn't exist (e.g. for the editor), check we get an error."""
+    filename = os.path.join(HERE, 'test-files', 'nope.bin')
+    with pytest.raises(FileNotFoundError):
+        _ = storage.get_config_from_file(filename)
+
+
 @with_pb2s
 def test_config_parses(storage_dump):
     """Test that we need the config_pb2 to exist/be compiled for reading the config to work."""