From 183a65b5326809968db47809dcb978af1c7e1386 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Wed, 17 Apr 2024 12:20:30 -0500
Subject: [PATCH 01/14] fix: Remove parenthesis around sole list items

Signed-off-by: cobalt <61329810+RedGuy12@users.noreply.github.com>
---
 docs/the_black_code_style/future_style.md     |  43 ++++-
 src/black/linegen.py                          |  29 +++-
 src/black/lines.py                            |   6 +-
 src/black/mode.py                             |   4 +-
 src/black/resources/black.schema.json         |   2 +-
 .../preview_remove_sole_list_item_parens.py   | 156 ++++++++++++++++++
 6 files changed, 228 insertions(+), 12 deletions(-)
 create mode 100644 tests/data/cases/preview_remove_sole_list_item_parens.py

diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index e0f45b47106..d60f9c7a999 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -47,8 +47,8 @@ The unstable style additionally includes the following features:
   ([see below](labels/wrap-long-dict-values))
 - `multiline_string_handling`: more compact formatting of expressions involving
   multiline strings ([see below](labels/multiline-string-handling))
-- `hug_parens_with_braces_and_square_brackets`: more compact formatting of nested
-  brackets ([see below](labels/hug-parens))
+- `condence_nested_brackets`: more compact formatting of nested brackets
+  ([see below](labels/hug-parens))
 
 (labels/hug-parens)=
 
@@ -124,6 +124,45 @@ foo(
 )
 ```
 
+Parenthesises around sole list items will also be removed for similar reasons. Trailing
+commas are respected here as well. For example:
+
+```python
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    )
+]
+
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+```
+
+will be changed to:
+
+```python
+items = [
+    long_variable_name
+    and even_longer_variable_name
+    and yet_another_very_long_variable_name
+]
+
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+```
+
 (labels/string-processing)=
 
 ### Improved string processing
diff --git a/src/black/linegen.py b/src/black/linegen.py
index 2d9c27a6141..efad4fca205 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -501,6 +501,19 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
 
         yield from self.visit_default(leaf)
 
+    def visit_atom(self, node: Node) -> Iterator[Line]:
+        """Visit any atom"""
+        if (
+            Preview.condence_nested_brackets in self.mode
+            and len(node.children) == 3
+            and node.children[0].type == token.LSQB
+            and node.children[-1].type == token.RSQB
+        ):
+            # Lists of one item
+            maybe_make_parens_invisible_in_atom(node.children[1], parent=node)
+
+        yield from self.visit_default(node)
+
     def __post_init__(self) -> None:
         """You are in a twisty little maze of passages."""
         self.current_line = Line(mode=self.mode)
@@ -811,7 +824,7 @@ def _first_right_hand_split(
 
     body: Optional[Line] = None
     if (
-        Preview.hug_parens_with_braces_and_square_brackets in line.mode
+        Preview.condence_nested_brackets in line.mode
         and tail_leaves[0].value
         and tail_leaves[0].opening_bracket is head_leaves[-1]
     ):
@@ -883,19 +896,25 @@ def _maybe_split_omitting_optional_parens(
     features: Collection[Feature] = (),
     omit: Collection[LeafID] = (),
 ) -> Iterator[Line]:
-    if (
+    both_optional_parens = (
         Feature.FORCE_OPTIONAL_PARENTHESES not in features
-        # the opening bracket is an optional paren
         and rhs.opening_bracket.type == token.LPAR
         and not rhs.opening_bracket.value
-        # the closing bracket is an optional paren
         and rhs.closing_bracket.type == token.RPAR
         and not rhs.closing_bracket.value
+    )
+    if (
+        # If both brackets are optional parens
+        both_optional_parens
         # it's not an import (optional parens are the only thing we can split on
         # in this case; attempting a split without them is a waste of time)
         and not line.is_import
         # and we can actually remove the parens
-        and can_omit_invisible_parens(rhs, mode.line_length)
+        and can_omit_invisible_parens(
+            rhs,
+            mode.line_length,
+            Preview.condence_nested_brackets in mode and line.inside_brackets,
+        )
     ):
         omit = {id(rhs.closing_bracket), *omit}
         try:
diff --git a/src/black/lines.py b/src/black/lines.py
index 6b65372fb3f..76531c3332a 100644
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -929,6 +929,7 @@ def can_be_split(line: Line) -> bool:
 def can_omit_invisible_parens(
     rhs: RHSResult,
     line_length: int,
+    inside_brackets: bool,
 ) -> bool:
     """Does `rhs.body` have a shape safe to reformat without optional parens around it?
 
@@ -962,8 +963,9 @@ def can_omit_invisible_parens(
     max_priority = bt.max_delimiter_priority()
     delimiter_count = bt.delimiter_count_with_priority(max_priority)
     if delimiter_count > 1:
-        # With more than one delimiter of a kind the optional parentheses read better.
-        return False
+        # With more than one delimiter of a kind the optional parentheses read
+        # better, but they're redundant if we're already inside brackets.
+        return inside_brackets
 
     if delimiter_count == 1:
         if max_priority == COMMA_PRIORITY and rhs.head.is_with_or_async_with_stmt:
diff --git a/src/black/mode.py b/src/black/mode.py
index b54f355e20a..88b6e76d30b 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -171,7 +171,7 @@ class Preview(Enum):
     # NOTE: string_processing requires wrap_long_dict_values_in_parens
     # for https://github.com/psf/black/issues/3117 to be fixed.
     string_processing = auto()
-    hug_parens_with_braces_and_square_brackets = auto()
+    condence_nested_brackets = auto()
     unify_docstring_detection = auto()
     no_normalize_fmt_skip_whitespace = auto()
     wrap_long_dict_values_in_parens = auto()
@@ -191,7 +191,7 @@ class Preview(Enum):
     # See issue #4159
     Preview.multiline_string_handling,
     # See issue #4036 (crash), #4098, #4099 (proposed tweaks)
-    Preview.hug_parens_with_braces_and_square_brackets,
+    Preview.condence_nested_brackets,
 }
 
 
diff --git a/src/black/resources/black.schema.json b/src/black/resources/black.schema.json
index 5c800775d57..12ac1bb7068 100644
--- a/src/black/resources/black.schema.json
+++ b/src/black/resources/black.schema.json
@@ -80,7 +80,7 @@
         "enum": [
           "hex_codes_in_unicode_sequences",
           "string_processing",
-          "hug_parens_with_braces_and_square_brackets",
+          "condence_nested_brackets",
           "unify_docstring_detection",
           "no_normalize_fmt_skip_whitespace",
           "wrap_long_dict_values_in_parens",
diff --git a/tests/data/cases/preview_remove_sole_list_item_parens.py b/tests/data/cases/preview_remove_sole_list_item_parens.py
new file mode 100644
index 00000000000..7cbd61e9b2a
--- /dev/null
+++ b/tests/data/cases/preview_remove_sole_list_item_parens.py
@@ -0,0 +1,156 @@
+# flags: --unstable
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "longstring"
+        else { "key": "val" }
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "longstring"
+        else { "key": "val" }
+    ),
+]
+items = [(
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "longstring"
+    else { "key": "val" }
+)]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "longstring"
+    else {"key": "val"}
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" }
+    )
+]
+items = [(
+    {"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" }
+)]
+items = [
+    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" }
+]
+items = [
+    ({"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" })
+]
+items = [({"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" })]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" }]
+
+items = [
+    (
+        "123456890123457890123468901234567890"
+        if some_var == "longstrings"
+        else "123467890123467890"
+    )
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "longstring"
+    and {"key": "val"}
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "longstrings"
+        and "123467890123467890"
+    )
+]
+items = [(
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "longstring"
+    and {"key": "val"}
+)]
+
+
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    )
+]
+
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+
+
+# output
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "longstring"
+    else {"key": "val"}
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "longstring"
+        else {"key": "val"}
+    ),
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "longstring"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "longstring"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+items = [
+    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+items = [
+    "123456890123457890123468901234567890"
+    if some_var == "longstrings"
+    else "123467890123467890"
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "longstring"
+    and {"key": "val"}
+]
+items = [
+    "123456890123457890123468901234567890"
+    and some_var == "longstrings"
+    and "123467890123467890"
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "longstring"
+    and {"key": "val"}
+]
+
+
+items = [
+    long_variable_name
+    and even_longer_variable_name
+    and yet_another_very_long_variable_name
+]
+
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]

From e8d291d7999094ecd1cac368ac2f3f91c21f45cd Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Wed, 17 Apr 2024 12:55:58 -0500
Subject: [PATCH 02/14] fix: Remove parenthesis around sole list items

Signed-off-by: cobalt <61329810+RedGuy12@users.noreply.github.com>
---
 CHANGES.md                                |  3 +++
 docs/the_black_code_style/future_style.md |  2 +-
 src/black/linegen.py                      | 18 ++++++------------
 src/black/lines.py                        | 11 +++--------
 src/black/mode.py                         |  4 ++--
 src/black/resources/black.schema.json     |  2 +-
 6 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index af756c79621..4708f41009a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -13,6 +13,9 @@
 ### Preview style
 
 <!-- Changes that affect Black's preview style -->
+- Remove parenthesis around sole list items and rename
+  `hug_parens_with_braces_and_square_brackets` unstable style to
+  `concise_nested_brackets` (#4312)
 
 ### Configuration
 
diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 4e33457001a..56248874192 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -47,7 +47,7 @@ The unstable style additionally includes the following features:
   ([see below](labels/wrap-long-dict-values))
 - `multiline_string_handling`: more compact formatting of expressions involving
   multiline strings ([see below](labels/multiline-string-handling))
-- `condence_nested_brackets`: more compact formatting of nested brackets
+- `concise_nested_brackets`: more compact formatting of nested brackets
   ([see below](labels/hug-parens))
 
 (labels/hug-parens)=
diff --git a/src/black/linegen.py b/src/black/linegen.py
index efad4fca205..6a9c8b57ca0 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -504,7 +504,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
     def visit_atom(self, node: Node) -> Iterator[Line]:
         """Visit any atom"""
         if (
-            Preview.condence_nested_brackets in self.mode
+            Preview.concise_nested_brackets in self.mode
             and len(node.children) == 3
             and node.children[0].type == token.LSQB
             and node.children[-1].type == token.RSQB
@@ -824,7 +824,7 @@ def _first_right_hand_split(
 
     body: Optional[Line] = None
     if (
-        Preview.condence_nested_brackets in line.mode
+        Preview.concise_nested_brackets in line.mode
         and tail_leaves[0].value
         and tail_leaves[0].opening_bracket is head_leaves[-1]
     ):
@@ -896,25 +896,19 @@ def _maybe_split_omitting_optional_parens(
     features: Collection[Feature] = (),
     omit: Collection[LeafID] = (),
 ) -> Iterator[Line]:
-    both_optional_parens = (
+    if (
         Feature.FORCE_OPTIONAL_PARENTHESES not in features
+        # the opening bracket is an optional paren
         and rhs.opening_bracket.type == token.LPAR
         and not rhs.opening_bracket.value
+        # the closing bracket is an optional paren
         and rhs.closing_bracket.type == token.RPAR
         and not rhs.closing_bracket.value
-    )
-    if (
-        # If both brackets are optional parens
-        both_optional_parens
         # it's not an import (optional parens are the only thing we can split on
         # in this case; attempting a split without them is a waste of time)
         and not line.is_import
         # and we can actually remove the parens
-        and can_omit_invisible_parens(
-            rhs,
-            mode.line_length,
-            Preview.condence_nested_brackets in mode and line.inside_brackets,
-        )
+        and can_omit_invisible_parens(rhs, mode.line_length)
     ):
         omit = {id(rhs.closing_bracket), *omit}
         try:
diff --git a/src/black/lines.py b/src/black/lines.py
index 76531c3332a..8f276c2dccb 100644
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -926,11 +926,7 @@ def can_be_split(line: Line) -> bool:
     return True
 
 
-def can_omit_invisible_parens(
-    rhs: RHSResult,
-    line_length: int,
-    inside_brackets: bool,
-) -> bool:
+def can_omit_invisible_parens(rhs: RHSResult, line_length: int) -> bool:
     """Does `rhs.body` have a shape safe to reformat without optional parens around it?
 
     Returns True for only a subset of potentially nice looking formattings but
@@ -963,9 +959,8 @@ def can_omit_invisible_parens(
     max_priority = bt.max_delimiter_priority()
     delimiter_count = bt.delimiter_count_with_priority(max_priority)
     if delimiter_count > 1:
-        # With more than one delimiter of a kind the optional parentheses read
-        # better, but they're redundant if we're already inside brackets.
-        return inside_brackets
+        # With more than one delimiter of a kind the optional parentheses read better.
+        return False
 
     if delimiter_count == 1:
         if max_priority == COMMA_PRIORITY and rhs.head.is_with_or_async_with_stmt:
diff --git a/src/black/mode.py b/src/black/mode.py
index 88b6e76d30b..10e37ccc460 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -171,7 +171,7 @@ class Preview(Enum):
     # NOTE: string_processing requires wrap_long_dict_values_in_parens
     # for https://github.com/psf/black/issues/3117 to be fixed.
     string_processing = auto()
-    condence_nested_brackets = auto()
+    concise_nested_brackets = auto()
     unify_docstring_detection = auto()
     no_normalize_fmt_skip_whitespace = auto()
     wrap_long_dict_values_in_parens = auto()
@@ -191,7 +191,7 @@ class Preview(Enum):
     # See issue #4159
     Preview.multiline_string_handling,
     # See issue #4036 (crash), #4098, #4099 (proposed tweaks)
-    Preview.condence_nested_brackets,
+    Preview.concise_nested_brackets,
 }
 
 
diff --git a/src/black/resources/black.schema.json b/src/black/resources/black.schema.json
index 12ac1bb7068..bff1033a823 100644
--- a/src/black/resources/black.schema.json
+++ b/src/black/resources/black.schema.json
@@ -80,7 +80,7 @@
         "enum": [
           "hex_codes_in_unicode_sequences",
           "string_processing",
-          "condence_nested_brackets",
+          "concise_nested_brackets",
           "unify_docstring_detection",
           "no_normalize_fmt_skip_whitespace",
           "wrap_long_dict_values_in_parens",

From fd49184c1e897de377ea4f3be4fd8432766556a3 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 17 Apr 2024 17:57:00 +0000
Subject: [PATCH 03/14] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 CHANGES.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGES.md b/CHANGES.md
index 4708f41009a..0820670feb3 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -13,6 +13,7 @@
 ### Preview style
 
 <!-- Changes that affect Black's preview style -->
+
 - Remove parenthesis around sole list items and rename
   `hug_parens_with_braces_and_square_brackets` unstable style to
   `concise_nested_brackets` (#4312)

From 40140e4232ed17fbaf59ef98f936ec7c58ce5b39 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Wed, 17 Apr 2024 12:57:38 -0500
Subject: [PATCH 04/14] Discard changes to src/black/lines.py

---
 src/black/lines.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/black/lines.py b/src/black/lines.py
index 8f276c2dccb..6b65372fb3f 100644
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -926,7 +926,10 @@ def can_be_split(line: Line) -> bool:
     return True
 
 
-def can_omit_invisible_parens(rhs: RHSResult, line_length: int) -> bool:
+def can_omit_invisible_parens(
+    rhs: RHSResult,
+    line_length: int,
+) -> bool:
     """Does `rhs.body` have a shape safe to reformat without optional parens around it?
 
     Returns True for only a subset of potentially nice looking formattings but

From 5ceaf93fd9b30bc76ec2321c6f51e7574c4ec759 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Wed, 17 Apr 2024 13:03:27 -0500
Subject: [PATCH 05/14] Add docs and tests for the simple cases lol

Signed-off-by: cobalt <61329810+RedGuy12@users.noreply.github.com>
---
 docs/the_black_code_style/future_style.md            | 10 ++++++++++
 .../cases/preview_remove_sole_list_item_parens.py    | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 56248874192..5496b0b05bd 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -128,6 +128,11 @@ Parenthesises around sole list items will also be removed for similar reasons. T
 commas are respected here as well. For example:
 
 ```python
+items = [(123)]
+items = [(True)]
+items = [((True,))]
+items = [(())]
+
 items = [
     (
         long_variable_name
@@ -148,6 +153,11 @@ items = [
 will be changed to:
 
 ```python
+items = [123]
+items = [True]
+items = [(True,)]
+items = [()]
+
 items = [
     long_variable_name
     and even_longer_variable_name
diff --git a/tests/data/cases/preview_remove_sole_list_item_parens.py b/tests/data/cases/preview_remove_sole_list_item_parens.py
index 7cbd61e9b2a..cdd968aadb8 100644
--- a/tests/data/cases/preview_remove_sole_list_item_parens.py
+++ b/tests/data/cases/preview_remove_sole_list_item_parens.py
@@ -1,4 +1,10 @@
 # flags: --unstable
+items = [(123)]
+items = [(True)]
+items = [(((((True)))))]
+items = [(((((True,)))))]
+items = [((((()))))]
+
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
@@ -84,6 +90,12 @@
 
 
 # output
+items = [123]
+items = [True]
+items = [True]
+items = [(True,)]
+items = [()]
+
 items = [
     {"key1": "val1", "key2": "val2", "key3": "val3"}
     if some_var == "longstring"

From bdb0a8a580f90f538f5121486cc5620da63e36ed Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Fri, 7 Jun 2024 15:57:38 -0500
Subject: [PATCH 06/14] Split into multiple features

Signed-off-by: cobalt <61329810+RedGuy12@users.noreply.github.com>
---
 CHANGES.md                                    |   4 +-
 docs/the_black_code_style/future_style.md     |  17 ++-
 src/black/linegen.py                          |   4 +-
 src/black/mode.py                             |   9 +-
 src/black/resources/black.schema.json         |   2 +-
 ...> preview_remove_lone_list_item_parens.py} | 110 ++++++++----------
 6 files changed, 73 insertions(+), 73 deletions(-)
 rename tests/data/cases/{preview_remove_sole_list_item_parens.py => preview_remove_lone_list_item_parens.py} (53%)

diff --git a/CHANGES.md b/CHANGES.md
index a5933af55ba..7f52ade6615 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -18,9 +18,7 @@
 
 <!-- Changes that affect Black's preview style -->
 
-- Remove parenthesis around sole list items and rename
-  `hug_parens_with_braces_and_square_brackets` unstable style to
-  `concise_nested_brackets` (#4312)
+- Remove parenthesis around sole list items (#4312)
 
 ### Configuration
 
diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 5496b0b05bd..6677b606e5f 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -47,8 +47,10 @@ The unstable style additionally includes the following features:
   ([see below](labels/wrap-long-dict-values))
 - `multiline_string_handling`: more compact formatting of expressions involving
   multiline strings ([see below](labels/multiline-string-handling))
-- `concise_nested_brackets`: more compact formatting of nested brackets
-  ([see below](labels/hug-parens))
+- `hug_parens_with_braces_and_square_brackets`: more compact formatting of nested
+  brackets ([see below](labels/hug-parens))
+- `remove_lone_list_item_parens`: remove redundant parenthesis around lone list items
+  ([see below](labels/lone-list-item-parens))
 
 (labels/hug-parens)=
 
@@ -124,7 +126,11 @@ foo(
 )
 ```
 
-Parenthesises around sole list items will also be removed for similar reasons. Trailing
+(labels/lone-list-item-parens)=
+
+### Remove keys around sole list item
+
+Parentheses around sole list items will also be removed for similar reasons. Trailing
 commas are respected here as well. For example:
 
 ```python
@@ -150,7 +156,7 @@ items = [
 ]
 ```
 
-will be changed to:
+will be formatted as:
 
 ```python
 items = [123]
@@ -173,6 +179,9 @@ items = [
 ]
 ```
 
+This style depends on `hug_parens_with_braces_and_square_brackets` to remove parenthesis
+in all cases.
+
 (labels/string-processing)=
 
 ### Improved string processing
diff --git a/src/black/linegen.py b/src/black/linegen.py
index 98bffcc1366..8e2d2f1c654 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -509,7 +509,7 @@ def visit_NUMBER(self, leaf: Leaf) -> Iterator[Line]:
     def visit_atom(self, node: Node) -> Iterator[Line]:
         """Visit any atom"""
         if (
-            Preview.concise_nested_brackets in self.mode
+            Preview.remove_lone_list_item_parens in self.mode
             and len(node.children) == 3
             and node.children[0].type == token.LSQB
             and node.children[-1].type == token.RSQB
@@ -868,7 +868,7 @@ def _first_right_hand_split(
 
     body: Optional[Line] = None
     if (
-        Preview.concise_nested_brackets in line.mode
+        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]
     ):
diff --git a/src/black/mode.py b/src/black/mode.py
index bef2f43bb31..c8c48235fd2 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -173,7 +173,7 @@ class Preview(Enum):
     # NOTE: string_processing requires wrap_long_dict_values_in_parens
     # for https://github.com/psf/black/issues/3117 to be fixed.
     string_processing = auto()
-    concise_nested_brackets = auto()
+    hug_parens_with_braces_and_square_brackets = auto()
     unify_docstring_detection = auto()
     no_normalize_fmt_skip_whitespace = auto()
     wrap_long_dict_values_in_parens = auto()
@@ -183,6 +183,9 @@ class Preview(Enum):
     docstring_check_for_newline = auto()
     remove_redundant_guard_parens = auto()
     parens_for_long_if_clauses_in_case_block = auto()
+    # NOTE: remove_lone_list_item_parens requires
+    # hug_parens_with_braces_and_square_brackets to remove parens in some cases
+    remove_lone_list_item_parens = auto()
 
 
 UNSTABLE_FEATURES: Set[Preview] = {
@@ -193,7 +196,9 @@ class Preview(Enum):
     # See issue #4159
     Preview.multiline_string_handling,
     # See issue #4036 (crash), #4098, #4099 (proposed tweaks)
-    Preview.concise_nested_brackets,
+    Preview.hug_parens_with_braces_and_square_brackets,
+    # Depends on hug_parens_with_braces_and_square_brackets
+    Preview.remove_lone_list_item_parens,
 }
 
 
diff --git a/src/black/resources/black.schema.json b/src/black/resources/black.schema.json
index bff1033a823..5c800775d57 100644
--- a/src/black/resources/black.schema.json
+++ b/src/black/resources/black.schema.json
@@ -80,7 +80,7 @@
         "enum": [
           "hex_codes_in_unicode_sequences",
           "string_processing",
-          "concise_nested_brackets",
+          "hug_parens_with_braces_and_square_brackets",
           "unify_docstring_detection",
           "no_normalize_fmt_skip_whitespace",
           "wrap_long_dict_values_in_parens",
diff --git a/tests/data/cases/preview_remove_sole_list_item_parens.py b/tests/data/cases/preview_remove_lone_list_item_parens.py
similarity index 53%
rename from tests/data/cases/preview_remove_sole_list_item_parens.py
rename to tests/data/cases/preview_remove_lone_list_item_parens.py
index cdd968aadb8..10f36ad4b23 100644
--- a/tests/data/cases/preview_remove_sole_list_item_parens.py
+++ b/tests/data/cases/preview_remove_lone_list_item_parens.py
@@ -8,69 +8,66 @@
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        if some_var == "longstring"
-        else { "key": "val" }
+        if some_var == "long strings"
+        else {"key": "val"}
     )
 ]
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        if some_var == "longstring"
-        else { "key": "val" }
+        if some_var == "long strings"
+        else {"key": "val"}
     ),
 ]
-items = [(
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "longstring"
-    else { "key": "val" }
-)]
 items = [
     {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "longstring"
+    if some_var == "long strings"
     else {"key": "val"}
 ]
 items = [
     (
-        {"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" }
+        {"key1": "val1", "key2": "val2"}
+        if some_var == ""
+        else {"key": "val"}
     )
 ]
-items = [(
-    {"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" }
-)]
-items = [
-    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" }
-]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
 items = [
-    ({"key1": "val1", "key2": "val2"} if some_var == "longstring" else { "key": "val" })
+    (
+        "123456890123457890123468901234567890"
+        if some_var == "long strings"
+        else "123467890123467890"
+    )
 ]
-items = [({"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" })]
-items = [{"key1": "val1", "key2": "val2"} if some_var == "" else { "key": "val" }]
 
 items = [
     (
-        "123456890123457890123468901234567890"
-        if some_var == "longstrings"
-        else "123467890123467890"
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
     )
 ]
 items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    and some_var == "longstring"
-    and {"key": "val"}
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
 ]
 items = [
     (
         "123456890123457890123468901234567890"
-        and some_var == "longstrings"
+        and some_var == "long strings"
         and "123467890123467890"
     )
 ]
-items = [(
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    and some_var == "longstring"
-    and {"key": "val"}
-)]
-
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
+]
 
 items = [
     (
@@ -79,7 +76,6 @@
         and yet_another_very_long_variable_name
     )
 ]
-
 items = [
     (
         long_variable_name
@@ -98,67 +94,59 @@
 
 items = [
     {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "longstring"
+    if some_var == "long strings"
     else {"key": "val"}
 ]
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        if some_var == "longstring"
+        if some_var == "long strings"
         else {"key": "val"}
     ),
 ]
 items = [
     {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "longstring"
+    if some_var == "long strings"
     else {"key": "val"}
 ]
-items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "longstring"
-    else {"key": "val"}
-]
-items = [
-    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
-]
 items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
-items = [
-    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
-]
-items = [
-    {"key1": "val1", "key2": "val2"} if some_var == "longstring" else {"key": "val"}
-]
 items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
-items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
-
 items = [
     "123456890123457890123468901234567890"
-    if some_var == "longstrings"
+    if some_var == "long strings"
     else "123467890123467890"
 ]
+
 items = [
     {"key1": "val1", "key2": "val2", "key3": "val3"}
-    and some_var == "longstring"
+    and some_var == "long strings"
     and {"key": "val"}
 ]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
+]
 items = [
     "123456890123457890123468901234567890"
-    and some_var == "longstrings"
+    and some_var == "long strings"
     and "123467890123467890"
 ]
 items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    and some_var == "longstring"
-    and {"key": "val"}
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
 ]
 
-
 items = [
     long_variable_name
     and even_longer_variable_name
     and yet_another_very_long_variable_name
 ]
-
 items = [
     (
         long_variable_name

From a7c9f5b601a8da986f0ea9d94230e9272738f4ab Mon Sep 17 00:00:00 2001
From: cobalt <61329810+RedGuy12@users.noreply.github.com>
Date: Fri, 7 Jun 2024 16:11:57 -0500
Subject: [PATCH 07/14] regen schema

Signed-off-by: cobalt <61329810+RedGuy12@users.noreply.github.com>
---
 src/black/resources/black.schema.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/black/resources/black.schema.json b/src/black/resources/black.schema.json
index 5c800775d57..c81de1ca4bb 100644
--- a/src/black/resources/black.schema.json
+++ b/src/black/resources/black.schema.json
@@ -89,7 +89,8 @@
           "is_simple_lookup_for_doublestar_expression",
           "docstring_check_for_newline",
           "remove_redundant_guard_parens",
-          "parens_for_long_if_clauses_in_case_block"
+          "parens_for_long_if_clauses_in_case_block",
+          "remove_lone_list_item_parens"
         ]
       },
       "description": "Enable specific features included in the `--unstable` style. Requires `--preview`. No compatibility guarantees are provided on the behavior or existence of any unstable features."

From a8515e3e4329ff072d13b2a211da3d3c694079d6 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Sat, 5 Oct 2024 20:12:43 -0500
Subject: [PATCH 08/14] Update future_style.md

---
 docs/the_black_code_style/future_style.md | 60 +----------------------
 1 file changed, 2 insertions(+), 58 deletions(-)

diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 328858875eb..8bb78c2655a 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -38,6 +38,8 @@ Currently, the following features are included in the preview style:
   blocks when the line is too long
 - `pep646_typed_star_arg_type_var_tuple`: fix type annotation spacing between * and more
   complex type variable tuple (i.e. `def fn(*args: *tuple[*Ts, T]) -> None: pass`)
+- `remove_lone_list_item_parens`: remove redundant parenthesis around lone list items
+  (depends on unstable `hug_parens_with_braces_and_square_brackets` feature in some cases)
 
 (labels/unstable-features)=
 
@@ -51,8 +53,6 @@ The unstable style additionally includes the following features:
   multiline strings ([see below](labels/multiline-string-handling))
 - `hug_parens_with_braces_and_square_brackets`: more compact formatting of nested
   brackets ([see below](labels/hug-parens))
-- `remove_lone_list_item_parens`: remove redundant parenthesis around lone list items
-  ([see below](labels/lone-list-item-parens))
 
 (labels/hug-parens)=
 
@@ -128,62 +128,6 @@ foo(
 )
 ```
 
-(labels/lone-list-item-parens)=
-
-### Remove keys around sole list item
-
-Parentheses around sole list items will also be removed for similar reasons. Trailing
-commas are respected here as well. For example:
-
-```python
-items = [(123)]
-items = [(True)]
-items = [((True,))]
-items = [(())]
-
-items = [
-    (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
-    )
-]
-
-items = [
-    (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
-    ),
-]
-```
-
-will be formatted as:
-
-```python
-items = [123]
-items = [True]
-items = [(True,)]
-items = [()]
-
-items = [
-    long_variable_name
-    and even_longer_variable_name
-    and yet_another_very_long_variable_name
-]
-
-items = [
-    (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
-    ),
-]
-```
-
-This style depends on `hug_parens_with_braces_and_square_brackets` to remove parenthesis
-in all cases.
-
 (labels/string-processing)=
 
 ### Improved string processing

From ee65f5ac1cf6209c32496d728600751e5ab40f39 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sun, 6 Oct 2024 01:13:08 +0000
Subject: [PATCH 09/14] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 docs/the_black_code_style/future_style.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 8bb78c2655a..9c22e82404c 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -39,7 +39,8 @@ Currently, the following features are included in the preview style:
 - `pep646_typed_star_arg_type_var_tuple`: fix type annotation spacing between * and more
   complex type variable tuple (i.e. `def fn(*args: *tuple[*Ts, T]) -> None: pass`)
 - `remove_lone_list_item_parens`: remove redundant parenthesis around lone list items
-  (depends on unstable `hug_parens_with_braces_and_square_brackets` feature in some cases)
+  (depends on unstable `hug_parens_with_braces_and_square_brackets` feature in some
+  cases)
 
 (labels/unstable-features)=
 

From 693790234d3a29ccde39e6a5e344564067e477f9 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Sat, 5 Oct 2024 20:13:34 -0500
Subject: [PATCH 10/14] Remove from unstable style

---
 src/black/mode.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/black/mode.py b/src/black/mode.py
index 109c7997f23..8ab71bce660 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -225,8 +225,6 @@ class Preview(Enum):
     Preview.multiline_string_handling,
     # See issue #4036 (crash), #4098, #4099 (proposed tweaks)
     Preview.hug_parens_with_braces_and_square_brackets,
-    # Depends on hug_parens_with_braces_and_square_brackets
-    Preview.remove_lone_list_item_parens,
 }
 
 

From 42864d759789966296815ecf5cc9642ab3b408fa Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Fri, 8 Nov 2024 16:56:33 -0600
Subject: [PATCH 11/14] typos

Signed-off-by: cobalt <61329810+cobaltt7@users.noreply.github.com>
---
 CHANGES.md                                | 3 ++-
 docs/the_black_code_style/future_style.md | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 20a90318ff9..8f374f30dd7 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -17,6 +17,8 @@
 
 <!-- Changes that affect Black's preview style -->
 
+- Remove parentheses around sole list items (#4312)
+
 ### Configuration
 
 <!-- Changes to how Black can be configured -->
@@ -74,7 +76,6 @@
 
 - Fix type annotation spacing between * and more complex type variable tuple (i.e. `def
   fn(*args: *tuple[*Ts, T]) -> None: pass`) (#4440)
-- Remove parenthesis around sole list items (#4312)
 
 ### Caching
 
diff --git a/docs/the_black_code_style/future_style.md b/docs/the_black_code_style/future_style.md
index 9c22e82404c..0b2e5f8b02c 100644
--- a/docs/the_black_code_style/future_style.md
+++ b/docs/the_black_code_style/future_style.md
@@ -38,7 +38,7 @@ Currently, the following features are included in the preview style:
   blocks when the line is too long
 - `pep646_typed_star_arg_type_var_tuple`: fix type annotation spacing between * and more
   complex type variable tuple (i.e. `def fn(*args: *tuple[*Ts, T]) -> None: pass`)
-- `remove_lone_list_item_parens`: remove redundant parenthesis around lone list items
+- `remove_lone_list_item_parens`: remove redundant parentheses around lone list items
   (depends on unstable `hug_parens_with_braces_and_square_brackets` feature in some
   cases)
 

From c87d2376d7a2397b067b1fae661227506a8c2f91 Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Sun, 10 Nov 2024 14:03:22 -0600
Subject: [PATCH 12/14] Update tests

Signed-off-by: cobalt <61329810+cobaltt7@users.noreply.github.com>
---
 src/black/linegen.py                          |   1 +
 .../preview_remove_lone_list_item_parens.py   | 162 ++++++------
 ..._remove_multiline_lone_list_item_parens.py | 246 ++++++++++++++++++
 3 files changed, 326 insertions(+), 83 deletions(-)
 create mode 100644 tests/data/cases/preview_remove_multiline_lone_list_item_parens.py

diff --git a/src/black/linegen.py b/src/black/linegen.py
index 783bbed3f00..a11e2465b83 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -1659,6 +1659,7 @@ def maybe_make_parens_invisible_in_atom(
             if first.prefix.strip():
                 # Preserve comments before first paren
                 middle.prefix = first.prefix + middle.prefix
+                first.prefix = ""
             last.value = ""
         maybe_make_parens_invisible_in_atom(
             middle,
diff --git a/tests/data/cases/preview_remove_lone_list_item_parens.py b/tests/data/cases/preview_remove_lone_list_item_parens.py
index 10f36ad4b23..4b296d29ea5 100644
--- a/tests/data/cases/preview_remove_lone_list_item_parens.py
+++ b/tests/data/cases/preview_remove_lone_list_item_parens.py
@@ -1,10 +1,13 @@
-# flags: --unstable
+# flags: --preview
 items = [(123)]
 items = [(True)]
 items = [(((((True)))))]
 items = [(((((True,)))))]
 items = [((((()))))]
+items = [(x for x in [1])]
 
+# Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
+# around multiline values
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
@@ -12,18 +15,6 @@
         else {"key": "val"}
     )
 ]
-items = [
-    (
-        {"key1": "val1", "key2": "val2", "key3": "val3"}
-        if some_var == "long strings"
-        else {"key": "val"}
-    ),
-]
-items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "long strings"
-    else {"key": "val"}
-]
 items = [
     (
         {"key1": "val1", "key2": "val2"}
@@ -31,58 +22,60 @@
         else {"key": "val"}
     )
 ]
-items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Comments should not cause crashes
 items = [
-    (
-        "123456890123457890123468901234567890"
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
         if some_var == "long strings"
-        else "123467890123467890"
+        else {"key": "val"}
     )
 ]
-
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        and some_var == "long strings"
-        and {"key": "val"}
-    )
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
 ]
-items = [
+
+items = [  # comment
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        and some_var == "long strings"
-        and {"key": "val"}
-    ),
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
 ]
 items = [
     (
-        "123456890123457890123468901234567890"
-        and some_var == "long strings"
-        and "123467890123467890"
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
     )
-]
+]  # comment
+
 items = [
     (
-        "123456890123457890123468901234567890"
-        and some_var == "long strings"
-        and "123467890123467890"
-    ),
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
 ]
 
-items = [
-    (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
     )
 ]
 items = [
     (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
-    ),
-]
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment
 
 
 # output
@@ -91,66 +84,69 @@
 items = [True]
 items = [(True,)]
 items = [()]
+items = [(x for x in [1])]
 
-items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "long strings"
-    else {"key": "val"}
-]
+# Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
+# around multiline values
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
         if some_var == "long strings"
         else {"key": "val"}
-    ),
-]
-items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    if some_var == "long strings"
-    else {"key": "val"}
+    )
 ]
 items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
-items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
-items = [
-    "123456890123457890123468901234567890"
-    if some_var == "long strings"
-    else "123467890123467890"
-]
 
+# Comments should not cause crashes
 items = [
-    {"key1": "val1", "key2": "val2", "key3": "val3"}
-    and some_var == "long strings"
-    and {"key": "val"}
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
 ]
 items = [
     (
         {"key1": "val1", "key2": "val2", "key3": "val3"}
-        and some_var == "long strings"
-        and {"key": "val"}
-    ),
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
 ]
-items = [
-    "123456890123457890123468901234567890"
-    and some_var == "long strings"
-    and "123467890123467890"
+
+items = [  # comment
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
 ]
 items = [
     (
-        "123456890123457890123468901234567890"
-        and some_var == "long strings"
-        and "123467890123467890"
-    ),
-]
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]  # comment
 
 items = [
-    long_variable_name
-    and even_longer_variable_name
-    and yet_another_very_long_variable_name
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
 ]
 items = [
     (
-        long_variable_name
-        and even_longer_variable_name
-        and yet_another_very_long_variable_name
-    ),
-]
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment
diff --git a/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py b/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py
new file mode 100644
index 00000000000..2acdd8bfdec
--- /dev/null
+++ b/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py
@@ -0,0 +1,246 @@
+# flags: --unstable
+items  = [(x for x in [1])]
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2"}
+        if some_var == ""
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        if some_var == "long strings"
+        else "123467890123467890"
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    )
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    )
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    )
+]
+
+# Shouldn't remove trailing commas
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    ),
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+
+# Shouldn't add parentheses
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Shouldn't crash with commas
+items = [
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]
+
+items = [  # comment
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]  # comment
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment
+
+
+# output
+items = [(x for x in [1])]
+
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+items = [
+    "123456890123457890123468901234567890"
+    if some_var == "long strings"
+    else "123467890123467890"
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "long strings"
+    and {"key": "val"}
+]
+items = [
+    "123456890123457890123468901234567890"
+    and some_var == "long strings"
+    and "123467890123467890"
+]
+items = [
+    long_variable_name
+    and even_longer_variable_name
+    and yet_another_very_long_variable_name
+]
+
+# Shouldn't remove trailing commas
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    ),
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+
+# Shouldn't add parentheses
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Shouldn't crash with commas
+items = [  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment
+
+items = [  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment
+
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+
+items = [  # comment  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment  # comment

From 84c059c1388d15dca4f629a89445a3e813f7f96e Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Sun, 24 Nov 2024 18:47:08 -0600
Subject: [PATCH 13/14] Finish PR I think hopefully

Signed-off-by: cobalt <61329810+cobaltt7@users.noreply.github.com>
---
 src/black/linegen.py                                  | 11 +++++++----
 .../preview_remove_multiline_lone_list_item_parens.py |  4 ++--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/black/linegen.py b/src/black/linegen.py
index a11e2465b83..a868c885218 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -1656,10 +1656,6 @@ def maybe_make_parens_invisible_in_atom(
             not is_type_ignore_comment_string(middle.prefix.strip())
         ):
             first.value = ""
-            if first.prefix.strip():
-                # Preserve comments before first paren
-                middle.prefix = first.prefix + middle.prefix
-                first.prefix = ""
             last.value = ""
         maybe_make_parens_invisible_in_atom(
             middle,
@@ -1671,6 +1667,13 @@ def maybe_make_parens_invisible_in_atom(
             # Strip the invisible parens from `middle` by replacing
             # it with the child in-between the invisible parens
             middle.replace(middle.children[1])
+
+            if middle.children[0].prefix.strip():
+                # Preserve comments before first paren
+                middle.children[1].prefix = (
+                    middle.children[0].prefix + middle.children[1].prefix
+                )
+
             if middle.children[-1].prefix.strip():
                 # Preserve comments before last paren
                 last.prefix = middle.children[-1].prefix + last.prefix
diff --git a/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py b/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py
index 2acdd8bfdec..08563026245 100644
--- a/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py
+++ b/tests/data/cases/preview_remove_multiline_lone_list_item_parens.py
@@ -82,7 +82,7 @@
 ]
 items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
 
-# Shouldn't crash with commas
+# Shouldn't crash with comments
 items = [
     (  # comment
         {"key1": "val1", "key2": "val2", "key3": "val3"}
@@ -205,7 +205,7 @@
 ]
 items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
 
-# Shouldn't crash with commas
+# Shouldn't crash with comments
 items = [  # comment
     {"key1": "val1", "key2": "val2", "key3": "val3"}
     if some_var == "long strings"

From 3e34a4cc0ce355ab0e17304808ff617470f8afbd Mon Sep 17 00:00:00 2001
From: cobalt <61329810+cobaltt7@users.noreply.github.com>
Date: Wed, 27 Nov 2024 17:41:09 -0600
Subject: [PATCH 14/14] Support sets

Signed-off-by: cobalt <61329810+cobaltt7@users.noreply.github.com>
---
 src/black/linegen.py                                  | 11 +++++++----
 .../cases/preview_remove_lone_list_item_parens.py     |  6 ++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/black/linegen.py b/src/black/linegen.py
index a868c885218..7bd018d31af 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -512,11 +512,14 @@ def visit_atom(self, node: Node) -> Iterator[Line]:
         if (
             Preview.remove_lone_list_item_parens in self.mode
             and len(node.children) == 3
-            and node.children[0].type == token.LSQB
-            and node.children[-1].type == token.RSQB
         ):
-            # Lists of one item
-            maybe_make_parens_invisible_in_atom(node.children[1], parent=node)
+            first = node.children[0]
+            last = node.children[-1]
+            if (first.type == token.LSQB and last.type == token.RSQB) or (
+                first.type == token.LBRACE and last.type == token.RBRACE
+            ):
+                # Lists or sets of one item
+                maybe_make_parens_invisible_in_atom(node.children[1], parent=node)
 
         yield from self.visit_default(node)
 
diff --git a/tests/data/cases/preview_remove_lone_list_item_parens.py b/tests/data/cases/preview_remove_lone_list_item_parens.py
index 4b296d29ea5..ad7058ba179 100644
--- a/tests/data/cases/preview_remove_lone_list_item_parens.py
+++ b/tests/data/cases/preview_remove_lone_list_item_parens.py
@@ -5,6 +5,9 @@
 items = [(((((True,)))))]
 items = [((((()))))]
 items = [(x for x in [1])]
+items = {(123)}
+items = {(True)}
+items = {(((((True)))))}
 
 # Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
 # around multiline values
@@ -85,6 +88,9 @@
 items = [(True,)]
 items = [()]
 items = [(x for x in [1])]
+items = {123}
+items = {True}
+items = {True}
 
 # Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
 # around multiline values