Fix #4011: Handle more huggable immediately nested parens/brackets.

CHANGES.md

@@ -13,8 +13,8 @@
 
 ### Preview style
 
-- Multiline dictionaries and lists that are the sole argument to a function are now
-  indented less (#3964)
+- Multiline tuples, lists, and dictionaries that are the sole argument to a function or
+  inside another tuple, list, or dictionary are now indented less (#3964, #4012)
 - Multiline list and dict unpacking as the sole argument to a function is now also
   indented less (#3992)
 

docs/conf.py

@@ -149,15 +149,13 @@ def make_pypi_svg(version: str) -> None:
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
-latex_documents = [
-    (
-        master_doc,
-        "black.tex",
-        "Documentation for Black",
-        "Łukasz Langa and contributors to Black",
-        "manual",
-    )
-]
+latex_documents = [(
+    master_doc,
+    "black.tex",
+    "Documentation for Black",
+    "Łukasz Langa and contributors to Black",
+    "manual",
+)]
 
 
 # -- Options for manual page output ------------------------------------------
@@ -172,17 +170,15 @@ def make_pypi_svg(version: str) -> None:
 # Grouping the document tree into Texinfo files. List of tuples
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
-texinfo_documents = [
-    (
-        master_doc,
-        "Black",
-        "Documentation for Black",
-        author,
-        "Black",
-        "The uncompromising Python code formatter",
-        "Miscellaneous",
-    )
-]
+texinfo_documents = [(
+    master_doc,
+    "Black",
+    "Documentation for Black",
+    author,
+    "Black",
+    "The uncompromising Python code formatter",
+    "Miscellaneous",
+)]
 
 
 # -- Options for Epub output -------------------------------------------------

docs/the_black_code_style/future_style.md

@@ -116,8 +116,7 @@ my_dict = {
 ### Improved multiline dictionary and list indentation for sole function parameter
 
 For better readability and less verticality, _Black_ now pairs parentheses ("(", ")")
-with braces ("{", "}") and square brackets ("[", "]") on the same line for single
-parameter function calls. For example:
+with braces ("{", "}") and square brackets ("[", "]") on the same line. For example:
 
 ```python
 foo(
@@ -127,6 +126,14 @@ foo(
         3,
     ]
 )
+
+nested_array = [
+    [
+        1,
+        2,
+        3,
+    ]
+]
 ```
 
 will be changed to:
@@ -137,6 +144,12 @@ foo([
     2,
     3,
 ])
+
+nested_array = [[
+    1,
+    2,
+    3,
+]]
 ```
 
 This also applies to list and dictionary unpacking:

src/black/handle_ipynb_magics.py

@@ -17,36 +17,30 @@
 from black.output import out
 from black.report import NothingChanged
 
-TRANSFORMED_MAGICS = frozenset(
-    (
-        "get_ipython().run_cell_magic",
-        "get_ipython().system",
-        "get_ipython().getoutput",
-        "get_ipython().run_line_magic",
-    )
-)
-TOKENS_TO_IGNORE = frozenset(
-    (
-        "ENDMARKER",
-        "NL",
-        "NEWLINE",
-        "COMMENT",
-        "DEDENT",
-        "UNIMPORTANT_WS",
-        "ESCAPED_NL",
-    )
-)
-PYTHON_CELL_MAGICS = frozenset(
-    (
-        "capture",
-        "prun",
-        "pypy",
-        "python",
-        "python3",
-        "time",
-        "timeit",
-    )
-)
+TRANSFORMED_MAGICS = frozenset((
+    "get_ipython().run_cell_magic",
+    "get_ipython().system",
+    "get_ipython().getoutput",
+    "get_ipython().run_line_magic",
+))
+TOKENS_TO_IGNORE = frozenset((
+    "ENDMARKER",
+    "NL",
+    "NEWLINE",
+    "COMMENT",
+    "DEDENT",
+    "UNIMPORTANT_WS",
+    "ESCAPED_NL",
+))
+PYTHON_CELL_MAGICS = frozenset((
+    "capture",
+    "prun",
+    "pypy",
+    "python",
+    "python3",
+    "time",
+    "timeit",
+))
 TOKEN_HEX = secrets.token_hex
 
 

src/black/linegen.py

@@ -817,18 +817,21 @@ def _first_right_hand_split(
     body_leaves.reverse()
     head_leaves.reverse()
 
-    if Preview.hug_parens_with_braces_and_square_brackets in line.mode:
+    if (
+        Preview.hug_parens_with_braces_and_square_brackets in line.mode
+        and tail_leaves[0].value
+        and tail_leaves[0].opening_bracket is head_leaves[-1]
+    ):
         is_unpacking = 1 if body_leaves[0].type in [token.STAR, token.DOUBLESTAR] else 0
-        if (
-            tail_leaves[0].type == token.RPAR
-            and tail_leaves[0].value
-            and tail_leaves[0].opening_bracket is head_leaves[-1]
-            and body_leaves[-1].type in [token.RBRACE, token.RSQB]
+        while (
+            len(body_leaves) >= 2 + is_unpacking
+            and body_leaves[-1].type in CLOSING_BRACKETS
             and body_leaves[-1].opening_bracket is body_leaves[is_unpacking]
         ):
             head_leaves = head_leaves + body_leaves[: 1 + is_unpacking]
             tail_leaves = body_leaves[-1:] + tail_leaves
             body_leaves = body_leaves[1 + is_unpacking : -1]
+            is_unpacking = 0
 
     head = bracket_split_build_line(
         head_leaves, line, opening_bracket, component=_BracketSplitComponent.head

src/black/lines.py

@@ -200,9 +200,9 @@ def is_triple_quoted_string(self) -> bool:
         value = self.leaves[0].value
         if value.startswith(('"""', "'''")):
             return True
-        if Preview.accept_raw_docstrings in self.mode and value.startswith(
-            ("r'''", 'r"""', "R'''", 'R"""')
-        ):
+        if Preview.accept_raw_docstrings in self.mode and value.startswith((
+            "r'''", 'r"""', "R'''", 'R"""'
+        )):
             return True
         return False
 

src/blackd/middlewares.py

@@ -36,9 +36,9 @@ async def impl(request: Request, handler: Handler) -> StreamResponse:
         resp.headers["Access-Control-Expose-Headers"] = "*"
         if is_options:
             resp.headers["Access-Control-Allow-Headers"] = ", ".join(allow_headers)
-            resp.headers["Access-Control-Allow-Methods"] = ", ".join(
-                ("OPTIONS", "POST")
-            )
+            resp.headers["Access-Control-Allow-Methods"] = ", ".join((
+                "OPTIONS", "POST"
+            ))
 
         return resp
 

src/blib2to3/pgen2/tokenize.py

@@ -314,9 +314,9 @@ def _get_normal_name(orig_enc: str) -> str:
     enc = orig_enc[:12].lower().replace("_", "-")
     if enc == "utf-8" or enc.startswith("utf-8-"):
         return "utf-8"
-    if enc in ("latin-1", "iso-8859-1", "iso-latin-1") or enc.startswith(
-        ("latin-1-", "iso-8859-1-", "iso-latin-1-")
-    ):
+    if enc in ("latin-1", "iso-8859-1", "iso-latin-1") or enc.startswith((
+        "latin-1-", "iso-8859-1-", "iso-latin-1-"
+    )):
         return "iso-8859-1"
     return orig_enc
 

tests/data/cases/preview_hug_parens_with_braces_and_square_brackets.py

@@ -128,6 +128,9 @@ def foo_square_brackets(request):
 func({"short line"})
 func({"long line", "long long line", "long long long line", "long long long long line", "long long long long long line"})
 func({{"long line", "long long line", "long long long line", "long long long long line", "long long long long long line"}})
+func(("long line", "long long line", "long long long line", "long long long long line", "long long long long long line"))
+func((("long line", "long long line", "long long long line", "long long long long line", "long long long long long line")))
+func([["long line", "long long line", "long long long line", "long long long long line", "long long long long long line"]])
 
 foooooooooooooooooooo(
     [{c: n + 1 for c in range(256)} for n in range(100)] + [{}], {size}
@@ -137,6 +140,10 @@ def foo_square_brackets(request):
     [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], {x}, "a string", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 )
 
+nested_mapping = {"key": [{"a very long key 1": "with a very long value", "a very long key 2": "with a very long value"}]}
+nested_array = [[["long line", "long long line", "long long long line", "long long long long line", "long long long long long line"]]]
+explicit_exploding = [[["short", "line",],],]
+
 foo(*["long long long long long line", "long long long long long line", "long long long long long line"])
 
 foo(*[str(i) for i in range(100000000000000000000000000000000000000000000000000000000000)])
@@ -285,15 +292,34 @@ def foo_square_brackets(request):
     "long long long long line",
     "long long long long long line",
 })
-func({
-    {
-        "long line",
-        "long long line",
-        "long long long line",
-        "long long long long line",
-        "long long long long long line",
-    }
-})
+func({{
+    "long line",
+    "long long line",
+    "long long long line",
+    "long long long long line",
+    "long long long long long line",
+}})
+func((
+    "long line",
+    "long long line",
+    "long long long line",
+    "long long long long line",
+    "long long long long long line",
+))
+func(((
+    "long line",
+    "long long line",
+    "long long long line",
+    "long long long long line",
+    "long long long long long line",
+)))
+func([[
+    "long line",
+    "long long line",
+    "long long long line",
+    "long long long long line",
+    "long long long long long line",
+]])
 
 foooooooooooooooooooo(
     [{c: n + 1 for c in range(256)} for n in range(100)] + [{}], {size}
@@ -303,6 +329,28 @@ def foo_square_brackets(request):
     [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], {x}, "a string", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 )
 
+nested_mapping = {
+    "key": [{
+        "a very long key 1": "with a very long value",
+        "a very long key 2": "with a very long value",
+    }]
+}
+nested_array = [[[
+    "long line",
+    "long long line",
+    "long long long line",
+    "long long long long line",
+    "long long long long long line",
+]]]
+explicit_exploding = [
+    [
+        [
+            "short",
+            "line",
+        ],
+    ],
+]
+
 foo(*[
     "long long long long long line",
     "long long long long long line",

tests/data/cases/preview_long_strings__regression.py

@@ -611,14 +611,13 @@ def foo():
 
 class A:
     def foo():
-        XXXXXXXXXXXX.append(
-            (
-                "xxx_xxxxxxxxxx(xxxxx={}, xxxx={}, xxxxx, xxxx_xxxx_xxxxxxxxxx={})"
-                .format(xxxxx, xxxx, xxxx_xxxx_xxxxxxxxxx),
-                my_var,
-                my_other_var,
-            )
-        )
+        XXXXXXXXXXXX.append((
+            "xxx_xxxxxxxxxx(xxxxx={}, xxxx={}, xxxxx, xxxx_xxxx_xxxxxxxxxx={})".format(
+                xxxxx, xxxx, xxxx_xxxx_xxxxxxxxxx
+            ),
+            my_var,
+            my_other_var,
+        ))
 
 
 class A: