fix indentation of line breaks in long type hints by adding parenthes…

…es, and remove unnecessary parentheses

src/black/linegen.py

@@ -397,6 +397,23 @@ def visit_factor(self, node: Node) -> Iterator[Line]:
             node.insert_child(index, Node(syms.atom, [lpar, operand, rpar]))
         yield from self.visit_default(node)
 
+    def visit_tname(self, node: Node) -> Iterator[Line]:
+        """
+        Add potential parentheses around types in function parameter lists to be made
+        into real parentheses in case the type hint is too long to fit on a line
+        Examples:
+        def foo(a: int, b: float = 7): ...
+
+        ->
+
+        def foo(a: (int), b: (float) = 7): ...
+        """
+        assert len(node.children) == 3
+        if maybe_make_parens_invisible_in_atom(node.children[2], parent=node):
+            wrap_in_parentheses(node, node.children[2], visible=False)
+
+        yield from self.visit_default(node)
+
     def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
         if Preview.hex_codes_in_unicode_sequences in self.mode:
             normalize_unicode_escape_sequences(leaf)
@@ -1368,7 +1385,7 @@ def maybe_make_parens_invisible_in_atom(
     Returns whether the node should itself be wrapped in invisible parentheses.
     """
     if (
-        node.type != syms.atom
+        node.type not in (syms.atom, syms.expr)
         or is_empty_tuple(node)
         or is_one_tuple(node)
         or (is_yield(node) and parent.type != syms.expr_stmt)
@@ -1392,6 +1409,7 @@ def maybe_make_parens_invisible_in_atom(
             syms.except_clause,
             syms.funcdef,
             syms.with_stmt,
+            syms.tname,
             # these ones aren't useful to end users, but they do please fuzzers
             syms.for_stmt,
             syms.del_stmt,

src/black/nodes.py

@@ -121,6 +121,8 @@
     ">>=",
     "**=",
     "//=",
+    # also handle annassign
+    ":",
 }
 
 IMPLICIT_TUPLE: Final = {syms.testlist, syms.testlist_star_expr, syms.exprlist}

tests/data/miscellaneous/long_strings_flag_disabled.py

@@ -254,7 +254,9 @@
     + CONCATENATED
     + "using the '+' operator."
 )
-annotated_variable: Final = "This is a large string that has a type annotation attached to it. A type annotation should NOT stop a long string from being wrapped."
+annotated_variable: (
+    Final
+) = "This is a large string that has a type annotation attached to it. A type annotation should NOT stop a long string from being wrapped."
 annotated_variable: Literal[
     "fakse_literal"
 ] = "This is a large string that has a type annotation attached to it. A type annotation should NOT stop a long string from being wrapped."

tests/data/preview/long_strings__type_annotations.py

@@ -54,6 +54,6 @@ def func(
 
 
 def func(
-    argument: ("int |" "str"),
+    argument: "int |" "str",
 ) -> Set["int |" " str"]:
     pass

tests/data/py_310/pep604_union_types_line_breaks.py

@@ -0,0 +1,190 @@
+# This has always worked
+z= Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong
+
+# "AnnAssign"s now also work
+z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong
+z: (Short
+    | Short2
+    | Short3
+    | Short4)
+z: (int)
+z: ((int))
+
+
+z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong = 7
+z: (Short
+    | Short2
+    | Short3
+    | Short4) = 8
+z: (int) = 2.3
+z: ((int)) = foo()
+
+# In case I go for not enforcing parantheses, this might get improved at the same time
+x = (
+    z
+    == 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999,
+    y
+    == 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999,
+)
+
+x = (
+    z == (9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999),
+    y == (9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999),
+)
+
+# handle formatting of "tname"s in parameter list
+
+# remove unnecessary paren
+def foo(i: (int)) -> None: ...
+
+
+# this is a syntax error in the type annotation according to mypy, but it's not invalid *python* code, so make sure we don't mess with it and make it so.
+def foo(i: (int,)) -> None: ...
+
+def foo(
+    i: int,
+    x: Loooooooooooooooooooooooong
+    | Looooooooooooooooong
+    | Looooooooooooooooooooong
+    | Looooooong,
+    *,
+    s: str,
+) -> None:
+    pass
+
+
+@app.get("/path/")
+async def foo(
+    q: str
+    | None = Query(None, title="Some long title", description="Some long description")
+):
+    pass
+
+
+def f(
+    max_jobs: int
+    | None = Option(
+        None, help="Maximum number of jobs to launch. And some additional text."
+        ),
+    another_option: bool = False
+    ):
+    ...
+
+
+# output
+# This has always worked
+z = (
+    Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+)
+
+# "AnnAssign"s now also work
+z: (
+    Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+)
+z: Short | Short2 | Short3 | Short4
+z: int
+z: int
+
+
+z: (
+    Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+    | Loooooooooooooooooooooooong
+) = 7
+z: Short | Short2 | Short3 | Short4 = 8
+z: int = 2.3
+z: int = foo()
+
+# In case I go for not enforcing parantheses, this might get improved at the same time
+x = (
+    z
+    == 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999
+    | 9999999999999999999999999999999999999999,
+    y
+    == 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999
+    + 9999999999999999999999999999999999999999,
+)
+
+x = (
+    z
+    == (
+        9999999999999999999999999999999999999999
+        | 9999999999999999999999999999999999999999
+        | 9999999999999999999999999999999999999999
+        | 9999999999999999999999999999999999999999
+    ),
+    y
+    == (
+        9999999999999999999999999999999999999999
+        + 9999999999999999999999999999999999999999
+        + 9999999999999999999999999999999999999999
+        + 9999999999999999999999999999999999999999
+    ),
+)
+
+# handle formatting of "tname"s in parameter list
+
+
+# remove unnecessary paren
+def foo(i: int) -> None:
+    ...
+
+
+# this is a syntax error in the type annotation according to mypy, but it's not invalid *python* code, so make sure we don't mess with it and make it so.
+def foo(i: (int,)) -> None:
+    ...
+
+
+def foo(
+    i: int,
+    x: (
+        Loooooooooooooooooooooooong
+        | Looooooooooooooooong
+        | Looooooooooooooooooooong
+        | Looooooong
+    ),
+    *,
+    s: str,
+) -> None:
+    pass
+
+
+@app.get("/path/")
+async def foo(
+    q: str | None = Query(
+        None, title="Some long title", description="Some long description"
+    )
+):
+    pass
+
+
+def f(
+    max_jobs: int | None = Option(
+        None, help="Maximum number of jobs to launch. And some additional text."
+    ),
+    another_option: bool = False,
+):
+    ...