Avoid partial conversions on % with dict r.h.s. - fixes #89

src/flynt/__init__.py

@@ -2,6 +2,6 @@
 from old "%-formatted" and .format(...) strings into Python 3.6+'s f-strings.
 Learn more about f-strings at https://www.python.org/dev/peps/pep-0498/"""
 
-__version__ = "0.62"
+__version__ = "0.63"
 
 from flynt.cli import main

src/flynt/transform/percent_transformer.py

@@ -13,6 +13,7 @@
 
 PREFIX_GROUP = "[0-9]*[.]?[0-9]*"
 
+ANY_DICT = re.compile(r"(?<!%)%\([^)]+?\)")
 DICT_PATTERN = re.compile(rf"(%\([^)]+\){PREFIX_GROUP}{FORMAT_GROUP})")
 SPLIT_DICT_PATTERN = re.compile(rf"%\(([^)]+)\)({PREFIX_GROUP}){FORMAT_GROUP_MATCH}")
 VAR_KEY_PATTERN = re.compile(
@@ -68,6 +69,11 @@ def transform_dict(node):
 
     format_str = node.left.s
     matches = DICT_PATTERN.findall(format_str)
+    if len(matches) != len(ANY_DICT.findall(format_str)):
+        raise FlyntException(
+            "Some locations have unknown format modifiers."
+        )
+
     spec = []
     for idx, m in enumerate(matches):
         _, var_key, prefix, fmt_str, _ = SPLIT_DICT_PATTERN.split(m)

test/test_process.py

@@ -454,3 +454,12 @@ def test_kv_loop():
 
     out, count = process.fstringify_code_by_line(s_in)
     assert out == expected
+
+
+def test_unknown_mod_percend_dictionary():
+    """Unknown modifier must not result in partial conversion!"""
+
+    s_in = """\"%(a)-6d %(a)s" % d"""
+
+    out, count = process.fstringify_code_by_line(s_in)
+    assert out == s_in