Replace astor with ast.unparse() and Black

pyproject.toml

@@ -30,6 +30,7 @@ classifiers = [
 ]
 dependencies = [
     "astor",
+    "black",
     "tomli>=1.1.0; python_version < '3.11'"
 ]
 

src/flynt/utils/utils.py

@@ -3,33 +3,16 @@
 import tokenize
 from typing import Optional, Union
 
-import astor
-from astor.string_repr import pretty_string
+from black import Mode, format_str
 
 from flynt.exceptions import ConversionRefused
 from flynt.linting.fstr_lint import FstrInliner
 from flynt.utils.format import QuoteTypes, set_quote_type
 
 
-def nicer_pretty_string(
-    s,
-    embedded,
-    current_line,
-    uni_lit=False,
-):
-    r = repr(s)
-    if "\\x" in r:
-        # If the string contains an escape sequence,
-        # we need to work around a bug in upstream astor;
-        # the easiest workaround is to just use the repr
-        # of the string and be done with it.
-        return r
-    return pretty_string(s, embedded, current_line, uni_lit=uni_lit)
-
-
 def ast_to_string(node: ast.AST) -> str:
-    # TODO: this could use `ast.unparse` when targeting Python 3.9+ only.
-    return astor.to_source(node, pretty_string=nicer_pretty_string).rstrip()
+    # ast.unparse() favors single quotes, use Black to turn them into double quotes
+    return format_str(ast.unparse(node), mode=Mode()).rstrip()
 
 
 def is_str_literal(node: ast.AST) -> bool:

test/integration/expected_out/multiline_keep.py

@@ -5,5 +5,5 @@
 
 [flake8]
 max-line-length={length}
-inline-quotes="{quotes}\"
+inline-quotes="{quotes}"
 """

test/test_str_concat/test_candidates.py

@@ -28,7 +28,7 @@ def test_find_victims_primitives(pycode_with_2_concats: str):
     assert len(ch.victims) == 2
 
     v1, v2 = ch.victims
-    assert str(v1) == "a + ' World'"
+    assert str(v1) == 'a + " World"'
     assert 'a + " World"' in pycode_with_2_concats.split("\n")[v1.start_line]
 
 
@@ -40,7 +40,7 @@ def test_find_victims_api(pycode_with_2_concats: str, state: State):
     assert len(lst) == 2
 
     v1, v2 = lst
-    assert str(v1) == "a + ' World'"
+    assert str(v1) == 'a + " World"'
     assert 'a + " World"' in pycode_with_2_concats.split("\n")[v1.start_line]
 
 
@@ -53,4 +53,4 @@ def test_find_victims_parens(state: State):
     assert len(lst) == 1
 
     v1 = lst[0]
-    assert str(v1) == """'blah' + (thing - 1)"""
+    assert str(v1) == '''"blah" + (thing - 1)'''

test/test_str_concat/test_transformer.py

@@ -90,7 +90,7 @@ def test_string_in_string():
 def test_concats_fstring():
 
     txt = """print(f'blah{thing}' + 'blah' + otherThing + f"is {x:d}")"""
-    expected = """print(f'blah{thing}blah{otherThing}is {x:d}')"""
+    expected = """print(f"blah{thing}blah{otherThing}is {x:d}")"""
 
     new, changed = transform_concat_from_str(txt)
 
@@ -105,7 +105,7 @@ def test_string_in_string_x3():
     new, changed = transform_concat_from_str(txt)
 
     assert changed
-    assert "'blah' +" in new
+    assert '"blah" +' in new
 
 
 def test_existing_fstr():
@@ -133,7 +133,7 @@ def test_existing_fstr_expr():
 def test_embedded_fstr():
 
     txt = """print(f"{f'blah{var}' + abc}blah")"""
-    expected = """print(f'blah{var}{abc}blah')"""
+    expected = """print(f"blah{var}{abc}blah")"""
 
     new, changed = transform_concat_from_str(txt)