Format DictComp expression (#5771)

## Summary

Format `DictComp` like `ListComp` from #5600. It's not 100%, but I
figured maybe it's worth starting to explore.

## Test Plan

Added ruff fixture based on `ListComp`'s.

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/dict_comp.py

@@ -0,0 +1,45 @@
+{i: i for i in []}
+
+{i: i for i in [1,]}
+
+{
+    a: a  # a
+    for # for
+    c  # c
+    in  # in
+    e  # e
+}
+
+{
+    # above a
+    a: a  # a
+    # above for
+    for # for
+    # above c
+    c  # c
+    # above in
+    in  # in
+    # above e
+    e  # e
+    # above if
+    if  # if
+    # above f
+    f  # f
+    # above if2
+    if  # if2
+    # above g
+    g  # g
+}
+
+{
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb + [dddddddddddddddddd, eeeeeeeeeeeeeeeeeee]: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    for
+    ccccccccccccccccccccccccccccccccccccccc,
+    ddddddddddddddddddd, [eeeeeeeeeeeeeeeeeeeeee, fffffffffffffffffffffffff]
+    in
+    eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeffffffffffffffffffffffffggggggggggggggggggggghhhhhhhhhhhhhhothermoreeand_even_moreddddddddddddddddddddd
+    if
+    fffffffffffffffffffffffffffffffffffffffffff < gggggggggggggggggggggggggggggggggggggggggggggg < hhhhhhhhhhhhhhhhhhhhhhhhhh
+    if
+    gggggggggggggggggggggggggggggggggggggggggggg
+}

crates/ruff_python_formatter/src/expression/expr_dict_comp.rs

@@ -1,6 +1,10 @@
 use crate::context::PyFormatContext;
-use crate::expression::parentheses::{NeedsParentheses, OptionalParentheses};
-use crate::{not_yet_implemented_custom_text, FormatNodeRule, PyFormatter};
+use crate::expression::parentheses::{parenthesized, NeedsParentheses, OptionalParentheses};
+use crate::AsFormat;
+use crate::{FormatNodeRule, FormattedIterExt, PyFormatter};
+use ruff_formatter::prelude::{
+    format_args, format_with, group, soft_line_break_or_space, space, text,
+};
 use ruff_formatter::{write, Buffer, FormatResult};
 use ruff_python_ast::node::AnyNodeRef;
 use rustpython_parser::ast::ExprDictComp;
@@ -9,11 +13,33 @@ use rustpython_parser::ast::ExprDictComp;
 pub struct FormatExprDictComp;
 
 impl FormatNodeRule<ExprDictComp> for FormatExprDictComp {
-    fn fmt_fields(&self, _item: &ExprDictComp, f: &mut PyFormatter) -> FormatResult<()> {
+    fn fmt_fields(&self, item: &ExprDictComp, f: &mut PyFormatter) -> FormatResult<()> {
+        let ExprDictComp {
+            range: _,
+            key,
+            value,
+            generators,
+        } = item;
+
+        let joined = format_with(|f| {
+            f.join_with(soft_line_break_or_space())
+                .entries(generators.iter().formatted())
+                .finish()
+        });
+
         write!(
             f,
-            [not_yet_implemented_custom_text(
-                "{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}"
+            [parenthesized(
+                "{",
+                &format_args!(
+                    group(&key.format()),
+                    text(":"),
+                    space(),
+                    value.format(),
+                    soft_line_break_or_space(),
+                    group(&joined)
+                ),
+                "}"
             )]
         )
     }

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap

@@ -316,27 +316,19 @@ last_call()
  ()
  (1,)
  (1, 2)
-@@ -95,14 +98,11 @@
- [(i**2) for i in (1, 2, 3)]
- [(i**2) for i, _ in ((1, "a"), (2, "b"), (3, "c"))]
- [((i**2) + j) for i in (1, 2, 3) for j in (1, 2, 3)]
--{i: 0 for i in (1, 2, 3)}
--{i: j for i, j in ((1, "a"), (2, "b"), (3, "c"))}
--{a: b * 2 for a, b in dictionary.items()}
--{a: b * -2 for a, b in dictionary.items()}
--{
--    k: v
+@@ -101,7 +104,10 @@
+ {a: b * -2 for a, b in dictionary.items()}
+ {
+     k: v
 -    for k, v in this_is_a_very_long_variable_which_will_cause_a_trailing_comma_which_breaks_the_comprehension
--}
-+{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-+{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-+{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-+{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-+{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
++    for (
++        k,
++        v,
++    ) in this_is_a_very_long_variable_which_will_cause_a_trailing_comma_which_breaks_the_comprehension
+ }
  Python3 > Python2 > COBOL
  Life is Life
- call()
-@@ -115,7 +115,7 @@
+@@ -115,7 +121,7 @@
      arg,
      another,
      kwarg="hey",
@@ -345,7 +337,7 @@ last_call()
  )  # note: no trailing comma pre-3.6
  call(*gidgets[:2])
  call(a, *gidgets[:2])
-@@ -152,13 +152,13 @@
+@@ -152,13 +158,13 @@
  slice[0:1]
  slice[0:1:2]
  slice[:]
@@ -362,7 +354,7 @@ last_call()
  numpy[0, :]
  numpy[:, i]
  numpy[0, :2]
-@@ -172,7 +172,7 @@
+@@ -172,7 +178,7 @@
  numpy[1 : c + 1, c]
  numpy[-(c + 1) :, d]
  numpy[:, l[-2]]
@@ -371,7 +363,7 @@ last_call()
  numpy[np.newaxis, :]
  (str or None) if (sys.version_info[0] > (3,)) else (str or bytes or None)
  {"2.7": dead, "3.7": long_live or die_hard}
-@@ -181,10 +181,10 @@
+@@ -181,10 +187,10 @@
  (SomeName)
  SomeName
  (Good, Bad, Ugly)
@@ -386,7 +378,7 @@ last_call()
  (*starred,)
  {
      "id": "1",
-@@ -208,24 +208,14 @@
+@@ -208,24 +214,14 @@
  what_is_up_with_those_new_coord_names = (coord_names | set(vars_to_create)) - set(
      vars_to_remove
  )
@@ -419,7 +411,7 @@ last_call()
  Ø = set()
  authors.łukasz.say_thanks()
  mapping = {
-@@ -237,10 +227,10 @@
+@@ -237,10 +233,10 @@
  
  
  def gen():
@@ -434,22 +426,16 @@ last_call()
  
  
  async def f():
-@@ -248,8 +238,12 @@
- 
+@@ -249,7 +245,7 @@
  
  print(*[] or [1])
--print(**{1: 3} if False else {x: x for x in range(3)})
+ print(**{1: 3} if False else {x: x for x in range(3)})
 -print(*lambda x: x)
-+print(
-+    **{1: 3}
-+    if False
-+    else {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-+)
 +print(*lambda NOT_YET_IMPLEMENTED_lambda: True)
  assert not Test, "Short message"
  assert this is ComplexTest and not requirements.fit_in_a_single_line(
      force=False
-@@ -259,7 +253,7 @@
+@@ -259,7 +255,7 @@
      ...
  for y in ():
      ...
@@ -458,7 +444,7 @@ last_call()
      ...
  for i in call():
      ...
-@@ -328,13 +322,18 @@
+@@ -328,13 +324,18 @@
  ):
      return True
  if (
@@ -480,7 +466,7 @@ last_call()
      ^ aaaaaaaa.i << aaaaaaaa.k >> aaaaaaaa.l**aaaaaaaa.m // aaaaaaaa.n
  ):
      return True
-@@ -342,7 +341,8 @@
+@@ -342,7 +343,8 @@
      ~aaaaaaaaaaaaaaaa.a
      + aaaaaaaaaaaaaaaa.b
      - aaaaaaaaaaaaaaaa.c * aaaaaaaaaaaaaaaa.d @ aaaaaaaaaaaaaaaa.e
@@ -595,11 +581,17 @@ str or None if (1 if True else 2) else str or bytes or None
 [(i**2) for i in (1, 2, 3)]
 [(i**2) for i, _ in ((1, "a"), (2, "b"), (3, "c"))]
 [((i**2) + j) for i in (1, 2, 3) for j in (1, 2, 3)]
-{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-{NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
+{i: 0 for i in (1, 2, 3)}
+{i: j for i, j in ((1, "a"), (2, "b"), (3, "c"))}
+{a: b * 2 for a, b in dictionary.items()}
+{a: b * -2 for a, b in dictionary.items()}
+{
+    k: v
+    for (
+        k,
+        v,
+    ) in this_is_a_very_long_variable_which_will_cause_a_trailing_comma_which_breaks_the_comprehension
+}
 Python3 > Python2 > COBOL
 Life is Life
 call()
@@ -735,11 +727,7 @@ async def f():
 
 
 print(*[] or [1])
-print(
-    **{1: 3}
-    if False
-    else {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
-)
+print(**{1: 3} if False else {x: x for x in range(3)})
 print(*lambda NOT_YET_IMPLEMENTED_lambda: True)
 assert not Test, "Short message"
 assert this is ComplexTest and not requirements.fit_in_a_single_line(

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__power_op_spacing.py.snap

@@ -84,15 +84,6 @@ return np.divide(
  f = f() ** 5
  g = a.b**c.d
  h = 5 ** funcs.f()
-@@ -26,7 +26,7 @@
- m = [([2**63], [1, 2**63])]
- n = count <= 10**5
- o = settings(max_examples=10**6)
--p = {(k, k**2): v**2 for k, v in pairs}
-+p = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
- q = [10**i for i in range(6)]
- r = x**y
- 
 @@ -34,7 +34,7 @@
  b = 5.0 ** f()
  c = -(5.0**2.0)
@@ -102,15 +93,6 @@ return np.divide(
  f = f() ** 5.0
  g = a.b**c.d
  h = 5.0 ** funcs.f()
-@@ -45,7 +45,7 @@
- m = [([2.0**63.0], [1.0, 2**63.0])]
- n = count <= 10**5.0
- o = settings(max_examples=10**6.0)
--p = {(k, k**2): v**2.0 for k, v in pairs}
-+p = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
- q = [10.5**i for i in range(6)]
- 
- 
 ```
 
 ## Ruff Output
@@ -144,7 +126,7 @@ l = mod.weights_[0] == pytest.approx(0.95**100, abs=0.001)
 m = [([2**63], [1, 2**63])]
 n = count <= 10**5
 o = settings(max_examples=10**6)
-p = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
+p = {(k, k**2): v**2 for k, v in pairs}
 q = [10**i for i in range(6)]
 r = x**y
 
@@ -163,7 +145,7 @@ l = mod.weights_[0] == pytest.approx(0.95**100, abs=0.001)
 m = [([2.0**63.0], [1.0, 2**63.0])]
 n = count <= 10**5.0
 o = settings(max_examples=10**6.0)
-p = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
+p = {(k, k**2): v**2.0 for k, v in pairs}
 q = [10.5**i for i in range(6)]
 
 

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__remove_parens.py.snap

@@ -96,44 +96,6 @@ def example8():
  
  
  def example4():
-@@ -50,35 +44,11 @@
- 
- 
- def example6():
--    return {a: a for a in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]}
-+    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
- 
- 
- def example7():
--    return {
--        a: a
--        for a in [
--            1,
--            2,
--            3,
--            4,
--            5,
--            6,
--            7,
--            8,
--            9,
--            10,
--            11,
--            12,
--            13,
--            14,
--            15,
--            16,
--            17,
--            18,
--            19,
--            20000000000000000000,
--        ]
--    }
-+    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
- 
- 
- def example8():
 ```
 
 ## Ruff Output
@@ -185,11 +147,35 @@ def example5():
 
 
 def example6():
-    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
+    return {a: a for a in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]}
 
 
 def example7():
-    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
+    return {
+        a: a
+        for a in [
+            1,
+            2,
+            3,
+            4,
+            5,
+            6,
+            7,
+            8,
+            9,
+            10,
+            11,
+            12,
+            13,
+            14,
+            15,
+            16,
+            17,
+            18,
+            19,
+            20000000000000000000,
+        ]
+    }
 
 
 def example8():

crates/ruff_python_formatter/tests/snapshots/format@expression__dict_comp.py.snap

@@ -0,0 +1,111 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/dict_comp.py
+---
+## Input
+```py
+{i: i for i in []}
+
+{i: i for i in [1,]}
+
+{
+    a: a  # a
+    for # for
+    c  # c
+    in  # in
+    e  # e
+}
+
+{
+    # above a
+    a: a  # a
+    # above for
+    for # for
+    # above c
+    c  # c
+    # above in
+    in  # in
+    # above e
+    e  # e
+    # above if
+    if  # if
+    # above f
+    f  # f
+    # above if2
+    if  # if2
+    # above g
+    g  # g
+}
+
+{
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb + [dddddddddddddddddd, eeeeeeeeeeeeeeeeeee]: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    for
+    ccccccccccccccccccccccccccccccccccccccc,
+    ddddddddddddddddddd, [eeeeeeeeeeeeeeeeeeeeee, fffffffffffffffffffffffff]
+    in
+    eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeffffffffffffffffffffffffggggggggggggggggggggghhhhhhhhhhhhhhothermoreeand_even_moreddddddddddddddddddddd
+    if
+    fffffffffffffffffffffffffffffffffffffffffff < gggggggggggggggggggggggggggggggggggggggggggggg < hhhhhhhhhhhhhhhhhhhhhhhhhh
+    if
+    gggggggggggggggggggggggggggggggggggggggggggg
+}
+```
+
+## Output
+```py
+{i: i for i in []}
+
+{
+    i: i
+    for i in [
+        1,
+    ]
+}
+
+{
+    a: a  # a
+    for c in e  # for  # c  # in  # e
+}
+
+{
+    # above a
+    a: a  # a
+    # above for
+    for  # for
+    # above c
+    c  # c
+    # above in
+    in  # in
+    # above e
+    e  # e
+    # above if
+    if  # if
+    # above f
+    f  # f
+    # above if2
+    if  # if2
+    # above g
+    g  # g
+}
+
+{
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+    + [
+        dddddddddddddddddd,
+        eeeeeeeeeeeeeeeeeee,
+    ]: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    for (
+        ccccccccccccccccccccccccccccccccccccccc,
+        ddddddddddddddddddd,
+        [eeeeeeeeeeeeeeeeeeeeee, fffffffffffffffffffffffff],
+    ) in eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeffffffffffffffffffffffffggggggggggggggggggggghhhhhhhhhhhhhhothermoreeand_even_moreddddddddddddddddddddd
+    if fffffffffffffffffffffffffffffffffffffffffff
+    < gggggggggggggggggggggggggggggggggggggggggggggg
+    < hhhhhhhhhhhhhhhhhhhhhhhhhh
+    if gggggggggggggggggggggggggggggggggggggggggggg
+}
+```
+
+
+