fix magic comma and experimental string cache flags (#2131)

[etc/vim.git] / src / black / __init__.py

diff --git a/src/black/__init__.py b/src/black/__init__.py
index 0a893aa80feba991670b3b51b726e7b5b194b833..00d3729c8354496812f9250d1f6f6f5530572cbe 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -273,9 +273,9 @@ class Mode:
     target_versions: Set[TargetVersion] = field(default_factory=set)
     line_length: int = DEFAULT_LINE_LENGTH
     string_normalization: bool = True
+    is_pyi: bool = False
     magic_trailing_comma: bool = True
     experimental_string_processing: bool = False
-    is_pyi: bool = False
 
     def get_cache_key(self) -> str:
         if self.target_versions:
@@ -290,6 +290,8 @@ class Mode:
             str(self.line_length),
             str(int(self.string_normalization)),
             str(int(self.is_pyi)),
+            str(int(self.magic_trailing_comma)),
+            str(int(self.experimental_string_processing)),
         ]
         return ".".join(parts)
 
@@ -1016,7 +1018,17 @@ def format_file_contents(src_contents: str, *, fast: bool, mode: Mode) -> FileCo
 
     if not fast:
         assert_equivalent(src_contents, dst_contents)
-        assert_stable(src_contents, dst_contents, mode=mode)
+
+        # Forced second pass to work around optional trailing commas (becoming
+        # forced trailing commas on pass 2) interacting differently with optional
+        # parentheses.  Admittedly ugly.
+        dst_contents_pass2 = format_str(dst_contents, mode=mode)
+        if dst_contents != dst_contents_pass2:
+            dst_contents = dst_contents_pass2
+            assert_equivalent(src_contents, dst_contents, pass_num=2)
+            assert_stable(src_contents, dst_contents, mode=mode)
+        # Note: no need to explicitly call `assert_stable` if `dst_contents` was
+        # the same as `dst_contents_pass2`.
     return dst_contents
 
 
@@ -6484,7 +6496,7 @@ def _stringify_ast(
     yield f"{'  ' * depth})  # /{node.__class__.__name__}"
 
 
-def assert_equivalent(src: str, dst: str) -> None:
+def assert_equivalent(src: str, dst: str, *, pass_num: int = 1) -> None:
     """Raise AssertionError if `src` and `dst` aren't equivalent."""
     try:
         src_ast = parse_ast(src)
@@ -6499,9 +6511,9 @@ def assert_equivalent(src: str, dst: str) -> None:
     except Exception as exc:
         log = dump_to_file("".join(traceback.format_tb(exc.__traceback__)), dst)
         raise AssertionError(
-            f"INTERNAL ERROR: Black produced invalid code: {exc}. Please report a bug"
-            " on https://github.com/psf/black/issues.  This invalid output might be"
-            f" helpful: {log}"
+            f"INTERNAL ERROR: Black produced invalid code on pass {pass_num}: {exc}. "
+            "Please report a bug on https://github.com/psf/black/issues.  "
+            f"This invalid output might be helpful: {log}"
         ) from None
 
     src_ast_str = "\n".join(_stringify_ast(src_ast))
@@ -6510,8 +6522,8 @@ def assert_equivalent(src: str, dst: str) -> None:
         log = dump_to_file(diff(src_ast_str, dst_ast_str, "src", "dst"))
         raise AssertionError(
             "INTERNAL ERROR: Black produced code that is not equivalent to the"
-            " source.  Please report a bug on https://github.com/psf/black/issues. "
-            f" This diff might be helpful: {log}"
+            f" source on pass {pass_num}.  Please report a bug on "
+            f"https://github.com/psf/black/issues.  This diff might be helpful: {log}"
         ) from None