fix: Don't remove parenthesis around long dictionary values

docs/contributing/release_process.md

@@ -29,8 +29,8 @@ frequently than monthly nets rapidly diminishing returns.
 **You must have `write` permissions for the _Black_ repository to cut a release.**
 
 The 10,000 foot view of the release process is that you prepare a release PR and then
-publish a [GitHub Release]. This triggers [release automation](#release-workflows) that
-builds all release artifacts and publishes them to the various platforms we publish to.
+publish a [GitHub Release]. This triggers [release automation](#release-workflows) that builds
+all release artifacts and publishes them to the various platforms we publish to.
 
 We now have a `scripts/release.py` script to help with cutting the release PRs.
 
@@ -96,9 +96,8 @@ In the end, use your best judgement and ask other maintainers for their thoughts
 
 ## Release workflows
 
-All of _Black_'s release automation uses [GitHub Actions]. All workflows are therefore
-configured using YAML files in the `.github/workflows` directory of the _Black_
-repository.
+All of _Black_'s release automation uses [GitHub Actions]. All workflows are therefore configured
+using YAML files in the `.github/workflows` directory of the _Black_ repository.
 
 They are triggered by the publication of a [GitHub Release].
 

docs/usage_and_configuration/black_docker_image.md

@@ -8,16 +8,16 @@ _Black_ images with the following tags are available:
 - release numbers, e.g. `21.5b2`, `21.6b0`, `21.7b0` etc.\
   ℹ Recommended for users who want to use a particular version of _Black_.
 - `latest_release` - tag created when a new version of _Black_ is released.\
-  ℹ Recommended for users who want to use released versions of _Black_. It maps to [the latest release](https://github.com/psf/black/releases/latest)
-  of _Black_.
+  ℹ Recommended for users who want to use released versions of _Black_. It maps to
+  [the latest release](https://github.com/psf/black/releases/latest) of _Black_.
 - `latest_prerelease` - tag created when a new alpha (prerelease) version of _Black_ is
   released.\
-  ℹ Recommended for users who want to preview or test alpha versions of _Black_. Note that
-  the most recent release may be newer than any prerelease, because no prereleases are created
-  before most releases.
+  ℹ Recommended for users who want to preview or test alpha versions of _Black_. Note
+  that the most recent release may be newer than any prerelease, because no prereleases
+  are created before most releases.
 - `latest` - tag used for the newest image of _Black_.\
-  ℹ Recommended for users who always want to use the latest version of _Black_, even before
-  it is released.
+  ℹ Recommended for users who always want to use the latest version of _Black_, even
+  before it is released.
 
 There is one more tag used for _Black_ Docker images - `latest_non_release`. It is
 created for all unreleased

src/black/lines.py

@@ -954,6 +954,21 @@ def can_omit_invisible_parens(
         ):
             closing_bracket = leaf
 
+    bracket = rhs.opening_bracket
+    if (
+        # Keep parenthesized dictionary values
+        bracket.parent
+        and bracket.parent.parent
+        and bracket.parent.parent.type == syms.dictsetmaker
+        # Unless key is a multiline function call (aka, with trailing comma)
+        and not (
+            len(rhs.head.leaves) >= 4
+            and rhs.head.leaves[-3].type == token.RPAR
+            and rhs.head.leaves[-4].type == token.COMMA
+        )
+    ):
+        return False
+
     bt = line.bracket_tracker
     if not bt.delimiters:
         # Without delimiters the optional parentheses are useless.

src/black/trans.py

@@ -886,6 +886,7 @@ class StringParenStripper(StringTransformer):
         The line contains a string which is surrounded by parentheses and:
             - The target string is NOT the only argument to a function call.
             - The target string is NOT a "pointless" string.
+            - The target string is NOT a dictionary value.
             - If the target string contains a PERCENT, the brackets are not
               preceded or followed by an operator with higher precedence than
               PERCENT.
@@ -933,11 +934,14 @@ def do_match(self, line: Line) -> TMatchResult:
             ):
                 continue
 
-            # That LPAR should NOT be preceded by a function name or a closing
-            # bracket (which could be a function which returns a function or a
-            # list/dictionary that contains a function)...
+            # That LPAR should NOT be preceded by a colon (which could be a
+            # dictionary value), function name, or a closing bracket (which
+            # could be a function returning a function or a list/dictionary
+            # containing a function)...
             if is_valid_index(idx - 2) and (
-                LL[idx - 2].type == token.NAME or LL[idx - 2].type in CLOSING_BRACKETS
+                LL[idx - 2].type == token.COLON
+                or LL[idx - 2].type == token.NAME
+                or LL[idx - 2].type in CLOSING_BRACKETS
             ):
                 continue
 
@@ -2263,12 +2267,12 @@ def do_transform(
             elif right_leaves and right_leaves[-1].type == token.RPAR:
                 # Special case for lambda expressions as dict's value, e.g.:
                 #     my_dict = {
-                #        "key": lambda x: f"formatted: {x},
+                #        "key": lambda x: f"formatted: {x}",
                 #     }
                 # After wrapping the dict's value with parentheses, the string is
                 # followed by a RPAR but its opening bracket is lambda's, not
                 # the string's:
-                #        "key": (lambda x: f"formatted: {x}),
+                #        "key": (lambda x: f"formatted: {x}"),
                 opening_bracket = right_leaves[-1].opening_bracket
                 if opening_bracket is not None and opening_bracket in left_leaves:
                     index = left_leaves.index(opening_bracket)

tests/data/cases/preview_long_dict_values_2.py

@@ -0,0 +1,162 @@
+# flags: --unstable
+
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx",
+}
+x = {
+    "foo": (bar),
+    "foo": bar,
+    "foo": xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx,
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+    )
+}
+
+# Function calls as keys
+tasks = {
+    get_key_name(foo, bar, baz,): src,
+    loop.run_in_executor(): src,
+    loop.run_in_executor(xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx): src,
+    loop.run_in_executor(xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxx): src,
+    loop.run_in_executor(): xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+}
+
+# Dictionary comprehensions
+tasks = {
+    key_name: xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    for src in sources
+}
+tasks = {key_name: foobar for src in sources}
+tasks = {get_key_name(src,): "foo" for src in sources}
+tasks = {get_key_name(foo, bar, baz,): src for src in sources}
+tasks = {
+    get_key_name(): xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    for src in sources
+}
+tasks = {
+    get_key_name(): foobar
+    for src in sources
+}
+
+# Delimiters inside the value
+def foo():
+    def bar():
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            common.models.DateTimeField: datetime(2020, 1, 31, tzinfo=utc) + timedelta(
+                days=i
+            ),
+        }
+        x = {
+            "foobar": (
+                123 + 456
+            ),
+        }
+        x = {
+            "foobar": (
+                123
+            ) + 456,
+        }
+
+
+# output
+
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    ),
+}
+x = {
+    "foo": bar,
+    "foo": bar,
+    "foo": (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+}
+
+# Function calls as keys
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src,
+    loop.run_in_executor(): src,
+    loop.run_in_executor(xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx): src,
+    loop.run_in_executor(
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxx,
+    ): src,
+    loop.run_in_executor(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+
+# Dictionary comprehensions
+tasks = {
+    key_name: (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {key_name: foobar for src in sources}
+tasks = {
+    get_key_name(
+        src,
+    ): "foo"
+    for src in sources
+}
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src
+    for src in sources
+}
+tasks = {
+    get_key_name(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {get_key_name(): foobar for src in sources}
+
+
+# Delimiters inside the value
+def foo():
+    def bar():
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            "foobar": 123 + 456,
+        }
+        x = {
+            "foobar": (123) + 456,
+        }