]> git.madduck.net Git - etc/vim.git/blobdiff - black.py

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

Remove unnecessary parens around yield (#834)
[etc/vim.git] / black.py
index c44bc9b46f6167f416f7c313acad509653bab8c7..cada4d0293a76482f558a59488f4bd0b7353d57e 100644 (file)
--- a/black.py
+++ b/black.py
@@ -68,7 +68,7 @@ LeafID = int
 Priority = int
 Index = int
 LN = Union[Leaf, Node]
-SplitFunc = Callable[["Line", bool], Iterator["Line"]]
+SplitFunc = Callable[["Line", Collection["Feature"]], Iterator["Line"]]
 Timestamp = float
 FileSize = int
 CacheInfo = Tuple[Timestamp, FileSize]
@@ -133,31 +133,35 @@ class Feature(Enum):
     UNICODE_LITERALS = 1
     F_STRINGS = 2
     NUMERIC_UNDERSCORES = 3
-    TRAILING_COMMA = 4
+    TRAILING_COMMA_IN_CALL = 4
+    TRAILING_COMMA_IN_DEF = 5
 
 
 VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
     TargetVersion.PY27: set(),
     TargetVersion.PY33: {Feature.UNICODE_LITERALS},
     TargetVersion.PY34: {Feature.UNICODE_LITERALS},
-    TargetVersion.PY35: {Feature.UNICODE_LITERALS, Feature.TRAILING_COMMA},
+    TargetVersion.PY35: {Feature.UNICODE_LITERALS, Feature.TRAILING_COMMA_IN_CALL},
     TargetVersion.PY36: {
         Feature.UNICODE_LITERALS,
         Feature.F_STRINGS,
         Feature.NUMERIC_UNDERSCORES,
-        Feature.TRAILING_COMMA,
+        Feature.TRAILING_COMMA_IN_CALL,
+        Feature.TRAILING_COMMA_IN_DEF,
     },
     TargetVersion.PY37: {
         Feature.UNICODE_LITERALS,
         Feature.F_STRINGS,
         Feature.NUMERIC_UNDERSCORES,
-        Feature.TRAILING_COMMA,
+        Feature.TRAILING_COMMA_IN_CALL,
+        Feature.TRAILING_COMMA_IN_DEF,
     },
     TargetVersion.PY38: {
         Feature.UNICODE_LITERALS,
         Feature.F_STRINGS,
         Feature.NUMERIC_UNDERSCORES,
-        Feature.TRAILING_COMMA,
+        Feature.TRAILING_COMMA_IN_CALL,
+        Feature.TRAILING_COMMA_IN_DEF,
     },
 }
 
@@ -522,12 +526,14 @@ async def schedule_formatting(
         manager = Manager()
         lock = manager.Lock()
     tasks = {
-        loop.run_in_executor(
-            executor, format_file_in_place, src, fast, mode, write_back, lock
+        asyncio.ensure_future(
+            loop.run_in_executor(
+                executor, format_file_in_place, src, fast, mode, write_back, lock
+            )
         ): src
         for src in sorted(sources)
     }
-    pending: Iterable[asyncio.Task] = tasks.keys()
+    pending: Iterable[asyncio.Future] = tasks.keys()
     try:
         loop.add_signal_handler(signal.SIGINT, cancel, pending)
         loop.add_signal_handler(signal.SIGTERM, cancel, pending)
@@ -683,6 +689,11 @@ def format_str(src_contents: str, *, mode: FileMode) -> FileContent:
     elt = EmptyLineTracker(is_pyi=mode.is_pyi)
     empty_line = Line()
     after = 0
+    split_line_features = {
+        feature
+        for feature in {Feature.TRAILING_COMMA_IN_CALL, Feature.TRAILING_COMMA_IN_DEF}
+        if supports_feature(versions, feature)
+    }
     for current_line in lines.visit(src_node):
         for _ in range(after):
             dst_contents += str(empty_line)
@@ -690,9 +701,7 @@ def format_str(src_contents: str, *, mode: FileMode) -> FileContent:
         for _ in range(before):
             dst_contents += str(empty_line)
         for line in split_line(
-            current_line,
-            line_length=mode.line_length,
-            supports_trailing_commas=supports_feature(versions, Feature.TRAILING_COMMA),
+            current_line, line_length=mode.line_length, features=split_line_features
         ):
             dst_contents += str(line)
     return dst_contents
@@ -715,24 +724,20 @@ def decode_bytes(src: bytes) -> Tuple[FileContent, Encoding, NewLine]:
         return tiow.read(), encoding, newline
 
 
-GRAMMARS = [
-    pygram.python_grammar_no_print_statement_no_exec_statement,
-    pygram.python_grammar_no_print_statement,
-    pygram.python_grammar,
-]
-
-
 def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
     if not target_versions:
-        return GRAMMARS
-    elif all(not version.is_python2() for version in target_versions):
-        # Python 3-compatible code, so don't try Python 2 grammar
+        # No target_version specified, so try all grammars.
         return [
             pygram.python_grammar_no_print_statement_no_exec_statement,
             pygram.python_grammar_no_print_statement,
+            pygram.python_grammar,
         ]
-    else:
+    elif all(version.is_python2() for version in target_versions):
+        # Python 2-only code, so try Python 2 grammars.
         return [pygram.python_grammar_no_print_statement, pygram.python_grammar]
+    else:
+        # Python 3-compatible code, so only try Python 3 grammar.
+        return [pygram.python_grammar_no_print_statement_no_exec_statement]
 
 
 def lib2to3_parse(src_txt: str, target_versions: Iterable[TargetVersion] = ()) -> Node:
@@ -2162,7 +2167,7 @@ def split_line(
     line: Line,
     line_length: int,
     inner: bool = False,
-    supports_trailing_commas: bool = False,
+    features: Collection[Feature] = (),
 ) -> Iterator[Line]:
     """Split a `line` into potentially many lines.
 
@@ -2171,7 +2176,7 @@ def split_line(
     current `line`, possibly transitively. This means we can fallback to splitting
     by delimiters if the LHS/RHS don't yield any results.
 
-    If `supports_trailing_commas` is True, splitting may use the TRAILING_COMMA feature.
+    `features` are syntactical features that may be used in the output.
     """
     if line.is_comment:
         yield line
@@ -2192,13 +2197,9 @@ def split_line(
         split_funcs = [left_hand_split]
     else:
 
-        def rhs(line: Line, supports_trailing_commas: bool = False) -> Iterator[Line]:
+        def rhs(line: Line, features: Collection[Feature]) -> Iterator[Line]:
             for omit in generate_trailers_to_omit(line, line_length):
-                lines = list(
-                    right_hand_split(
-                        line, line_length, supports_trailing_commas, omit=omit
-                    )
-                )
+                lines = list(right_hand_split(line, line_length, features, omit=omit))
                 if is_line_short_enough(lines[0], line_length=line_length):
                     yield from lines
                     return
@@ -2206,7 +2207,7 @@ def split_line(
             # All splits failed, best effort split with no omits.
             # This mostly happens to multiline strings that are by definition
             # reported as not fitting a single line.
-            yield from right_hand_split(line, supports_trailing_commas)
+            yield from right_hand_split(line, line_length, features=features)
 
         if line.inside_brackets:
             split_funcs = [delimiter_split, standalone_comment_split, rhs]
@@ -2218,16 +2219,13 @@ def split_line(
         # split altogether.
         result: List[Line] = []
         try:
-            for l in split_func(line, supports_trailing_commas):
+            for l in split_func(line, features):
                 if str(l).strip("\n") == line_str:
                     raise CannotSplit("Split function returned an unchanged result")
 
                 result.extend(
                     split_line(
-                        l,
-                        line_length=line_length,
-                        inner=True,
-                        supports_trailing_commas=supports_trailing_commas,
+                        l, line_length=line_length, inner=True, features=features
                     )
                 )
         except CannotSplit:
@@ -2241,9 +2239,7 @@ def split_line(
         yield line
 
 
-def left_hand_split(
-    line: Line, supports_trailing_commas: bool = False
-) -> Iterator[Line]:
+def left_hand_split(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
     """Split line into many lines, starting with the first matching bracket pair.
 
     Note: this usually looks weird, only use this for function definitions.
@@ -2282,7 +2278,7 @@ def left_hand_split(
 def right_hand_split(
     line: Line,
     line_length: int,
-    supports_trailing_commas: bool = False,
+    features: Collection[Feature] = (),
     omit: Collection[LeafID] = (),
 ) -> Iterator[Line]:
     """Split line into many lines, starting with the last matching bracket pair.
@@ -2341,12 +2337,7 @@ def right_hand_split(
     ):
         omit = {id(closing_bracket), *omit}
         try:
-            yield from right_hand_split(
-                line,
-                line_length,
-                supports_trailing_commas=supports_trailing_commas,
-                omit=omit,
-            )
+            yield from right_hand_split(line, line_length, features=features, omit=omit)
             return
 
         except CannotSplit:
@@ -2414,10 +2405,17 @@ def bracket_split_build_line(
         if leaves:
             # Since body is a new indent level, remove spurious leading whitespace.
             normalize_prefix(leaves[0], inside_brackets=True)
-            # Ensure a trailing comma when expected.
+            # Ensure a trailing comma for imports, but be careful not to add one after
+            # any comments.
             if original.is_import:
-                if leaves[-1].type != token.COMMA:
-                    leaves.append(Leaf(token.COMMA, ","))
+                for i in range(len(leaves) - 1, -1, -1):
+                    if leaves[i].type == STANDALONE_COMMENT:
+                        continue
+                    elif leaves[i].type == token.COMMA:
+                        break
+                    else:
+                        leaves.insert(i + 1, Leaf(token.COMMA, ","))
+                        break
     # Populate the line
     for leaf in leaves:
         result.append(leaf, preformatted=True)
@@ -2435,10 +2433,8 @@ def dont_increase_indentation(split_func: SplitFunc) -> SplitFunc:
     """
 
     @wraps(split_func)
-    def split_wrapper(
-        line: Line, supports_trailing_commas: bool = False
-    ) -> Iterator[Line]:
-        for l in split_func(line, supports_trailing_commas):
+    def split_wrapper(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
+        for l in split_func(line, features):
             normalize_prefix(l.leaves[0], inside_brackets=True)
             yield l
 
@@ -2446,13 +2442,11 @@ def dont_increase_indentation(split_func: SplitFunc) -> SplitFunc:
 
 
 @dont_increase_indentation
-def delimiter_split(
-    line: Line, supports_trailing_commas: bool = False
-) -> Iterator[Line]:
+def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
     """Split according to delimiters of the highest priority.
 
-    If `supports_trailing_commas` is True, the split will add trailing commas
-    also in function signatures that contain `*` and `**`.
+    If the appropriate Features are given, the split will add trailing commas
+    also in function signatures and calls that contain `*` and `**`.
     """
     try:
         last_leaf = line.leaves[-1]
@@ -2491,10 +2485,16 @@ def delimiter_split(
             yield from append_to_line(comment_after)
 
         lowest_depth = min(lowest_depth, leaf.bracket_depth)
-        if leaf.bracket_depth == lowest_depth and is_vararg(
-            leaf, within=VARARGS_PARENTS
-        ):
-            trailing_comma_safe = trailing_comma_safe and supports_trailing_commas
+        if leaf.bracket_depth == lowest_depth:
+            if is_vararg(leaf, within={syms.typedargslist}):
+                trailing_comma_safe = (
+                    trailing_comma_safe and Feature.TRAILING_COMMA_IN_DEF in features
+                )
+            elif is_vararg(leaf, within={syms.arglist, syms.argument}):
+                trailing_comma_safe = (
+                    trailing_comma_safe and Feature.TRAILING_COMMA_IN_CALL in features
+                )
+
         leaf_priority = bt.delimiters.get(id(leaf))
         if leaf_priority == delimiter_priority:
             yield current_line
@@ -2513,7 +2513,7 @@ def delimiter_split(
 
 @dont_increase_indentation
 def standalone_comment_split(
-    line: Line, supports_trailing_commas: bool = False
+    line: Line, features: Collection[Feature] = ()
 ) -> Iterator[Line]:
     """Split standalone comments from the rest of the line."""
     if not line.contains_standalone_comments(0):
@@ -2728,7 +2728,7 @@ def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
     for index, child in enumerate(list(node.children)):
         if check_lpar:
             if child.type == syms.atom:
-                if maybe_make_parens_invisible_in_atom(child):
+                if maybe_make_parens_invisible_in_atom(child, parent=node):
                     lpar = Leaf(token.LPAR, "")
                     rpar = Leaf(token.RPAR, "")
                     index = child.remove() or 0
@@ -2839,7 +2839,7 @@ def generate_ignored_nodes(leaf: Leaf) -> Iterator[LN]:
         container = container.next_sibling
 
 
-def maybe_make_parens_invisible_in_atom(node: LN) -> bool:
+def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
     """If it's safe, make the parens in the atom `node` invisible, recursively.
 
     Returns whether the node should itself be wrapped in invisible parentheses.
@@ -2849,7 +2849,7 @@ def maybe_make_parens_invisible_in_atom(node: LN) -> bool:
         node.type != syms.atom
         or is_empty_tuple(node)
         or is_one_tuple(node)
-        or is_yield(node)
+        or (is_yield(node) and parent.type != syms.expr_stmt)
         or max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
     ):
         return False
@@ -2861,7 +2861,7 @@ def maybe_make_parens_invisible_in_atom(node: LN) -> bool:
         first.value = ""  # type: ignore
         last.value = ""  # type: ignore
         if len(node.children) > 1:
-            maybe_make_parens_invisible_in_atom(node.children[1])
+            maybe_make_parens_invisible_in_atom(node.children[1], parent=parent)
         return False
 
     return True
@@ -3063,14 +3063,19 @@ def get_features_used(node: Node) -> Set[Feature]:
             and n.children
             and n.children[-1].type == token.COMMA
         ):
+            if n.type == syms.typedargslist:
+                feature = Feature.TRAILING_COMMA_IN_DEF
+            else:
+                feature = Feature.TRAILING_COMMA_IN_CALL
+
             for ch in n.children:
                 if ch.type in STARS:
-                    features.add(Feature.TRAILING_COMMA)
+                    features.add(feature)
 
                 if ch.type == syms.argument:
                     for argch in ch.children:
                         if argch.type in STARS:
-                            features.add(Feature.TRAILING_COMMA)
+                            features.add(feature)
 
     return features
 
@@ -3150,7 +3155,7 @@ def get_future_imports(node: Node) -> Set[str]:
             elif child.type == syms.import_as_names:
                 yield from get_imports_from_children(child.children)
             else:
-                assert False, "Invalid syntax parsing imports"
+                raise AssertionError("Invalid syntax parsing imports")
 
     for child in node.children:
         if child.type != syms.simple_stmt:
@@ -3390,7 +3395,7 @@ def assert_equivalent(src: str, dst: str) -> None:
         log = dump_to_file("".join(traceback.format_tb(exc.__traceback__)), dst)
         raise AssertionError(
             f"INTERNAL ERROR: Black produced invalid code: {exc}. "
-            f"Please report a bug on https://github.com/ambv/black/issues.  "
+            f"Please report a bug on https://github.com/python/black/issues.  "
             f"This invalid output might be helpful: {log}"
         ) from None
 
@@ -3401,7 +3406,7 @@ def assert_equivalent(src: str, dst: str) -> None:
         raise AssertionError(
             f"INTERNAL ERROR: Black produced code that is not equivalent to "
             f"the source.  "
-            f"Please report a bug on https://github.com/ambv/black/issues.  "
+            f"Please report a bug on https://github.com/python/black/issues.  "
             f"This diff might be helpful: {log}"
         ) from None
 
@@ -3417,7 +3422,7 @@ def assert_stable(src: str, dst: str, mode: FileMode) -> None:
         raise AssertionError(
             f"INTERNAL ERROR: Black produced different code on the second pass "
             f"of the formatter.  "
-            f"Please report a bug on https://github.com/ambv/black/issues.  "
+            f"Please report a bug on https://github.com/python/black/issues.  "
             f"This diff might be helpful: {log}"
         ) from None