Fix assert formatting instability

crates/ruff_python_formatter/src/other/f_string_element.rs

@@ -57,7 +57,8 @@ impl<'a> FormatFStringLiteralElement<'a> {
 impl Format<PyFormatContext<'_>> for FormatFStringLiteralElement<'_> {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
         let literal_content = f.context().locator().slice(self.element.range());
-        let normalized = normalize_string(literal_content, 0, self.context.flags(), true, false);
+        let normalized =
+            normalize_string(literal_content, 0, self.context.flags(), false, false, true);
         match &normalized {
             Cow::Borrowed(_) => source_text_slice(self.element.range()).fmt(f),
             Cow::Owned(normalized) => text(normalized).fmt(f),

crates/ruff_python_formatter/src/statement/stmt_assert.rs

@@ -34,7 +34,7 @@ impl FormatNodeRule<StmtAssert> for FormatStmtAssert {
                 [
                     token(","),
                     space(),
-                    maybe_parenthesize_expression(msg, item, Parenthesize::IfBreaks),
+                    maybe_parenthesize_expression(msg, item, Parenthesize::IfBreaksParenthesized),
                 ]
             )?;
         }

crates/ruff_python_formatter/src/string/mod.rs

@@ -174,15 +174,17 @@ impl Format<PyFormatContext<'_>> for FormatImplicitConcatenatedString<'_> {
                 write!(f, [flags.prefix(), quotes])?;
 
                 // TODO: strings in expression statements aren't joined correctly because they aren't wrap in a group :(
+                // TODO: FStrings when the f-string preview style is enabled???
 
                 for part in self.string.parts() {
                     let content = f.context().locator().slice(part.content_range());
                     let normalized = normalize_string(
                         content,
                         0,
                         flags,
-                        is_f_string_formatting_enabled(f.context()),
                         flags.is_f_string() && !part.flags().is_f_string(),
+                        true,
+                        false,
                     );
                     match normalized {
                         Cow::Borrowed(_) => source_text_slice(part.content_range()).fmt(f)?,

crates/ruff_python_formatter/src/string/normalize.rs

@@ -196,8 +196,9 @@ impl<'a, 'src> StringNormalizer<'a, 'src> {
                 quote_selection.flags,
                 // TODO: Remove the `b'{'` in `choose_quotes` when promoting the
                 // `format_fstring` preview style
-                is_f_string_formatting_enabled(self.context),
                 false,
+                false,
+                is_f_string_formatting_enabled(self.context),
             )
         } else {
             Cow::Borrowed(raw_content)
@@ -517,8 +518,9 @@ pub(crate) fn normalize_string(
     input: &str,
     start_offset: usize,
     new_flags: AnyStringFlags,
-    format_f_string: bool,
     escape_braces: bool,
+    flip_nested_fstring_quotes: bool,
+    format_f_string: bool,
 ) -> Cow<str> {
     // The normalized string if `input` is not yet normalized.
     // `output` must remain empty if `input` is already normalized.
@@ -626,6 +628,16 @@ pub(crate) fn normalize_string(
                 output.push(c);
                 last_index = index + preferred_quote.len_utf8();
             }
+            // TODO: Don't normalize inner quotes if f-string formatting is enabled.
+            else if c == preferred_quote
+                && flip_nested_fstring_quotes
+                && formatted_value_nesting > 0
+            {
+                // Flip the quotes
+                output.push_str(&input[last_index..index]);
+                output.push(opposite_quote);
+                last_index = index + preferred_quote.len_utf8();
+            }
         }
     }
 
@@ -789,6 +801,7 @@ mod tests {
 
     use super::UnicodeEscape;
     use crate::string::normalize_string;
+    use ruff_python_ast::str_prefix::FStringPrefix;
     use ruff_python_ast::{
         str::Quote,
         str_prefix::{AnyStringPrefix, ByteStringPrefix},
@@ -817,10 +830,35 @@ mod tests {
                 Quote::Double,
                 false,
             ),
-            true,
             false,
+            false,
+            true,
         );
 
         assert_eq!(r"\x89\x50\x4e\x47\x0d\x0a\x1a\x0a", &normalized);
     }
+
+    #[test]
+    fn normalize_nested_fstring() {
+        let input =
+            r#"With single quote: '  {my_dict['foo']} With double quote: "  {my_dict["bar"]}"#;
+
+        let normalized = normalize_string(
+            input,
+            0,
+            AnyStringFlags::new(
+                AnyStringPrefix::Format(FStringPrefix::Regular),
+                Quote::Double,
+                false,
+            ),
+            false,
+            true,
+            false,
+        );
+
+        assert_eq!(
+            "With single quote: '  {my_dict['foo']} With double quote: \\\"  {my_dict['bar']}",
+            &normalized
+        );
+    }
 }

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

@@ -193,41 +193,7 @@ class C:
 ```diff
 --- Black
 +++ Ruff
-@@ -110,19 +110,20 @@
-             value, is_going_to_be="too long to fit in a single line", srsly=True
-         ), "Not what we expected"
- 
--        assert {
--            key1: value1,
--            key2: value2,
--            key3: value3,
--            key4: value4,
--            key5: value5,
--            key6: value6,
--            key7: value7,
--            key8: value8,
--            key9: value9,
--        } == expected, (
--            "Not what we expected and the message is too long to fit in one line"
--        )
-+        assert (
-+            {
-+                key1: value1,
-+                key2: value2,
-+                key3: value3,
-+                key4: value4,
-+                key5: value5,
-+                key6: value6,
-+                key7: value7,
-+                key8: value8,
-+                key9: value9,
-+            }
-+            == expected
-+        ), "Not what we expected and the message is too long to fit in one line"
- 
-         assert expected(
-             value, is_going_to_be="too long to fit in a single line", srsly=True
-@@ -161,9 +162,7 @@
+@@ -161,9 +161,7 @@
                        8 STORE_ATTR               0 (x)
                       10 LOAD_CONST               0 (None)
                       12 RETURN_VALUE
@@ -355,20 +321,19 @@ class C:
             value, is_going_to_be="too long to fit in a single line", srsly=True
         ), "Not what we expected"
 
-        assert (
-            {
-                key1: value1,
-                key2: value2,
-                key3: value3,
-                key4: value4,
-                key5: value5,
-                key6: value6,
-                key7: value7,
-                key8: value8,
-                key9: value9,
-            }
-            == expected
-        ), "Not what we expected and the message is too long to fit in one line"
+        assert {
+            key1: value1,
+            key2: value2,
+            key3: value3,
+            key4: value4,
+            key5: value5,
+            key6: value6,
+            key7: value7,
+            key8: value8,
+            key9: value9,
+        } == expected, (
+            "Not what we expected and the message is too long to fit in one line"
+        )
 
         assert expected(
             value, is_going_to_be="too long to fit in a single line", srsly=True
@@ -610,5 +575,3 @@ class C:
             }
         )
 ```
-
-

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

@@ -193,41 +193,7 @@ class C:
 ```diff
 --- Black
 +++ Ruff
-@@ -110,19 +110,20 @@
-             value, is_going_to_be="too long to fit in a single line", srsly=True
-         ), "Not what we expected"
- 
--        assert {
--            key1: value1,
--            key2: value2,
--            key3: value3,
--            key4: value4,
--            key5: value5,
--            key6: value6,
--            key7: value7,
--            key8: value8,
--            key9: value9,
--        } == expected, (
--            "Not what we expected and the message is too long to fit in one line"
--        )
-+        assert (
-+            {
-+                key1: value1,
-+                key2: value2,
-+                key3: value3,
-+                key4: value4,
-+                key5: value5,
-+                key6: value6,
-+                key7: value7,
-+                key8: value8,
-+                key9: value9,
-+            }
-+            == expected
-+        ), "Not what we expected and the message is too long to fit in one line"
- 
-         assert expected(
-             value, is_going_to_be="too long to fit in a single line", srsly=True
-@@ -161,9 +162,7 @@
+@@ -161,9 +161,7 @@
                        8 STORE_ATTR               0 (x)
                       10 LOAD_CONST               0 (None)
                       12 RETURN_VALUE
@@ -355,20 +321,19 @@ class C:
             value, is_going_to_be="too long to fit in a single line", srsly=True
         ), "Not what we expected"
 
-        assert (
-            {
-                key1: value1,
-                key2: value2,
-                key3: value3,
-                key4: value4,
-                key5: value5,
-                key6: value6,
-                key7: value7,
-                key8: value8,
-                key9: value9,
-            }
-            == expected
-        ), "Not what we expected and the message is too long to fit in one line"
+        assert {
+            key1: value1,
+            key2: value2,
+            key3: value3,
+            key4: value4,
+            key5: value5,
+            key6: value6,
+            key7: value7,
+            key8: value8,
+            key9: value9,
+        } == expected, (
+            "Not what we expected and the message is too long to fit in one line"
+        )
 
         assert expected(
             value, is_going_to_be="too long to fit in a single line", srsly=True
@@ -610,5 +575,3 @@ class C:
             }
         )
 ```
-
-

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

@@ -275,6 +275,19 @@ last_call()
  )  # note: no trailing comma pre-3.6
  call(*gidgets[:2])
  call(a, *gidgets[:2])
+@@ -251,9 +251,9 @@
+ print(**{1: 3} if False else {x: x for x in range(3)})
+ print(*lambda x: x)
+ assert not Test, "Short message"
+-assert this is ComplexTest and not requirements.fit_in_a_single_line(
+-    force=False
+-), "Short message"
++assert this is ComplexTest and not requirements.fit_in_a_single_line(force=False), (
++    "Short message"
++)
+ assert parens is TooMany
+ for (x,) in (1,), (2,), (3,):
+     ...
 ```
 
 ## Ruff Output
@@ -533,9 +546,9 @@ print(*[] or [1])
 print(**{1: 3} if False else {x: x for x in range(3)})
 print(*lambda x: x)
 assert not Test, "Short message"
-assert this is ComplexTest and not requirements.fit_in_a_single_line(
-    force=False
-), "Short message"
+assert this is ComplexTest and not requirements.fit_in_a_single_line(force=False), (
+    "Short message"
+)
 assert parens is TooMany
 for (x,) in (1,), (2,), (3,):
     ...
@@ -1028,5 +1041,3 @@ bbbb >> bbbb * bbbb
 last_call()
 # standalone comment at ENDMARKER
 ```
-
-

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

@@ -308,23 +308,29 @@ long_unmergable_string_with_pragma = (
 ```diff
 --- Black
 +++ Ruff
-@@ -167,13 +167,9 @@
+@@ -167,14 +167,14 @@
 
  triple_quote_string = """This is a really really really long triple quote string assignment and it should not be touched."""
 
 -assert (
 -    some_type_of_boolean_expression
 -), "Followed by a really really really long string that is used to provide context to the AssertionError exception."
-+assert some_type_of_boolean_expression, "Followed by a really really really long string that is used to provide context to the AssertionError exception."
++assert some_type_of_boolean_expression, (
++    "Followed by a really really really long string that is used to provide context to the AssertionError exception."
++)
 
 -assert (
 -    some_type_of_boolean_expression
 -), "Followed by a really really really long string that is used to provide context to the AssertionError exception, which uses dynamic string {}.".format(
-+assert some_type_of_boolean_expression, "Followed by a really really really long string that is used to provide context to the AssertionError exception, which uses dynamic string {}.".format(
-     "formatting"
+-    "formatting"
++assert some_type_of_boolean_expression, (
++    "Followed by a really really really long string that is used to provide context to the AssertionError exception, which uses dynamic string {}.".format(
++        "formatting"
++    )
  )
 
-@@ -256,9 +252,7 @@
+ assert some_type_of_boolean_expression, (
+@@ -256,9 +256,7 @@
      + CONCATENATED
      + "using the '+' operator."
  )
@@ -509,10 +515,14 @@ pragma_comment_string2 = "Lines which end with an inline pragma comment of the f
 
 triple_quote_string = """This is a really really really long triple quote string assignment and it should not be touched."""
 
-assert some_type_of_boolean_expression, "Followed by a really really really long string that is used to provide context to the AssertionError exception."
+assert some_type_of_boolean_expression, (
+    "Followed by a really really really long string that is used to provide context to the AssertionError exception."
+)
 
-assert some_type_of_boolean_expression, "Followed by a really really really long string that is used to provide context to the AssertionError exception, which uses dynamic string {}.".format(
-    "formatting"
+assert some_type_of_boolean_expression, (
+    "Followed by a really really really long string that is used to provide context to the AssertionError exception, which uses dynamic string {}.".format(
+        "formatting"
+    )
 )
 
 assert some_type_of_boolean_expression, (