[isort] Add support for length-sort settings (#8841)

## Summary

Closes #1567.

Add both `length-sort` and `length-sort-straight` settings for isort.

Here are a few notable points:
- The length is determined using the
[`unicode_width`](https://crates.io/crates/unicode-width) crate, i.e. we
are talking about displayed length (this is explicitly mentioned in the
description of the setting)
- The dots are taken into account in the length to be compatible with
the original isort
- I had to reorder a few fields of the module key struct for it all to
make sense (notably the `force_to_top` field is now the first one)

## Test Plan

I added tests for the following cases:
- Basic tests for length-sort with ASCII characters only
- Tests with non-ASCII characters
- Tests with relative imports
- Tests for length-sort-straight

crates/ruff_linter/resources/test/fixtures/isort/length_sort_from_imports.py

@@ -0,0 +1,3 @@
+from mediuuuuuuuuuuum import a
+from short import b
+from loooooooooooooooooooooog import c

crates/ruff_linter/resources/test/fixtures/isort/length_sort_non_ascii_members.py

@@ -0,0 +1,11 @@
+from module1 import (
+    loooooooooooooong,
+    σηορτ,
+    mediuuuuum,
+    shoort,
+    looooooooooooooong,
+    μεδιυυυυυμ,
+    short,
+    mediuuuuuum,
+    λοοοοοοοοοοοοοονγ,
+)

crates/ruff_linter/resources/test/fixtures/isort/length_sort_non_ascii_modules.py

@@ -0,0 +1,9 @@
+import loooooooooooooong
+import mediuuuuuum
+import short
+import σηορτ
+import shoort
+import mediuuuuum
+import λοοοοοοοοοοοοοονγ
+import μεδιυυυυυμ
+import looooooooooooooong

crates/ruff_linter/resources/test/fixtures/isort/length_sort_straight_and_from_imports.py

@@ -0,0 +1,6 @@
+import mediuuuuuum
+import short
+import looooooooooooooooong
+from looooooooooooooong import a
+from mediuuuum import c
+from short import b

crates/ruff_linter/resources/test/fixtures/isort/length_sort_straight_imports.py

@@ -0,0 +1,4 @@
+import mediuuuuuumb
+import short
+import looooooooooooooooong
+import mediuuuuuuma

crates/ruff_linter/resources/test/fixtures/isort/length_sort_with_relative_imports.py

@@ -0,0 +1,7 @@
+from ..looooooooooooooong import a
+from ...mediuuuum import b
+from .short import c
+from ....short import c
+from . import d
+from .mediuuuum import a
+from ......short import b

crates/ruff_linter/resources/test/fixtures/isort/length_sort_with_star_import.py

@@ -0,0 +1,3 @@
+from looooooooooooooong import a
+from mediuuuum import *
+from short import *

crates/ruff_linter/src/rules/isort/mod.rs

@@ -1138,4 +1138,47 @@ mod tests {
         assert_messages!(diagnostics);
         Ok(())
     }
+
+    #[test_case(Path::new("length_sort_straight_imports.py"))]
+    #[test_case(Path::new("length_sort_from_imports.py"))]
+    #[test_case(Path::new("length_sort_straight_and_from_imports.py"))]
+    #[test_case(Path::new("length_sort_non_ascii_members.py"))]
+    #[test_case(Path::new("length_sort_non_ascii_modules.py"))]
+    #[test_case(Path::new("length_sort_with_relative_imports.py"))]
+    fn length_sort(path: &Path) -> Result<()> {
+        let snapshot = format!("length_sort__{}", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("isort").join(path).as_path(),
+            &LinterSettings {
+                isort: super::settings::Settings {
+                    length_sort: true,
+                    ..super::settings::Settings::default()
+                },
+                src: vec![test_resource_path("fixtures/isort")],
+                ..LinterSettings::for_rule(Rule::UnsortedImports)
+            },
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
+
+    #[test_case(Path::new("length_sort_straight_imports.py"))]
+    #[test_case(Path::new("length_sort_from_imports.py"))]
+    #[test_case(Path::new("length_sort_straight_and_from_imports.py"))]
+    fn length_sort_straight(path: &Path) -> Result<()> {
+        let snapshot = format!("length_sort_straight__{}", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("isort").join(path).as_path(),
+            &LinterSettings {
+                isort: super::settings::Settings {
+                    length_sort_straight: true,
+                    ..super::settings::Settings::default()
+                },
+                src: vec![test_resource_path("fixtures/isort")],
+                ..LinterSettings::for_rule(Rule::UnsortedImports)
+            },
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
 }

crates/ruff_linter/src/rules/isort/order.rs

@@ -1,3 +1,4 @@
+use crate::rules::isort::sorting::ImportStyle;
 use itertools::Itertools;
 
 use super::settings::Settings;
@@ -56,21 +57,34 @@ pub(crate) fn order_imports<'a>(
             .map(Import)
             .chain(from_imports.map(ImportFrom))
             .sorted_by_cached_key(|import| match import {
-                Import((alias, _)) => {
+                Import((alias, _)) => ModuleKey::from_module(
-                    ModuleKey::from_module(Some(alias.name), alias.asname, None, None, settings)
+                    Some(alias.name),
-                }
+                    alias.asname,
+                    None,
+                    None,
+                    ImportStyle::Straight,
+                    settings,
+                ),
                 ImportFrom((import_from, _, _, aliases)) => ModuleKey::from_module(
                     import_from.module,
                     None,
                     import_from.level,
                     aliases.first().map(|(alias, _)| (alias.name, alias.asname)),
+                    ImportStyle::From,
                     settings,
                 ),
             })
             .collect()
     } else {
         let ordered_straight_imports = straight_imports.sorted_by_cached_key(|(alias, _)| {
-            ModuleKey::from_module(Some(alias.name), alias.asname, None, None, settings)
+            ModuleKey::from_module(
+                Some(alias.name),
+                alias.asname,
+                None,
+                None,
+                ImportStyle::Straight,
+                settings,
+            )
         });
         let ordered_from_imports =
             from_imports.sorted_by_cached_key(|(import_from, _, _, aliases)| {
@@ -79,6 +93,7 @@ pub(crate) fn order_imports<'a>(
                     None,
                     import_from.level,
                     aliases.first().map(|(alias, _)| (alias.name, alias.asname)),
+                    ImportStyle::From,
                     settings,
                 )
             });

crates/ruff_linter/src/rules/isort/settings.rs

@@ -58,6 +58,8 @@ pub struct Settings {
     pub section_order: Vec<ImportSection>,
     pub no_sections: bool,
     pub from_first: bool,
+    pub length_sort: bool,
+    pub length_sort_straight: bool,
 }
 
 impl Default for Settings {
@@ -86,6 +88,8 @@ impl Default for Settings {
             section_order: ImportType::iter().map(ImportSection::Known).collect(),
             no_sections: false,
             from_first: false,
+            length_sort: false,
+            length_sort_straight: false,
         }
     }
 }

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_from_imports.py.snap

@@ -0,0 +1,18 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_from_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / from mediuuuuuuuuuuum import a
+2 | | from short import b
+3 | | from loooooooooooooooooooooog import c
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+from short import b
+1 2 | from mediuuuuuuuuuuum import a
+2   |-from short import b
+3 3 | from loooooooooooooooooooooog import c
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_non_ascii_members.py.snap

@@ -0,0 +1,37 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_non_ascii_members.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+   |
+ 1 | / from module1 import (
+ 2 | |     loooooooooooooong,
+ 3 | |     σηορτ,
+ 4 | |     mediuuuuum,
+ 5 | |     shoort,
+ 6 | |     looooooooooooooong,
+ 7 | |     μεδιυυυυυμ,
+ 8 | |     short,
+ 9 | |     mediuuuuuum,
+10 | |     λοοοοοοοοοοοοοονγ,
+11 | | )
+   |
+   = help: Organize imports
+
+ℹ Safe fix
+1  1  | from module1 import (
+2     |-    loooooooooooooong,
+   2  |+    short,
+3  3  |     σηορτ,
+   4  |+    shoort,
+4  5  |     mediuuuuum,
+5     |-    shoort,
+6     |-    looooooooooooooong,
+7  6  |     μεδιυυυυυμ,
+8     |-    short,
+9  7  |     mediuuuuuum,
+   8  |+    loooooooooooooong,
+10 9  |     λοοοοοοοοοοοοοονγ,
+   10 |+    looooooooooooooong,
+11 11 | )
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_non_ascii_modules.py.snap

@@ -0,0 +1,32 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_non_ascii_modules.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / import loooooooooooooong
+2 | | import mediuuuuuum
+3 | | import short
+4 | | import σηορτ
+5 | | import shoort
+6 | | import mediuuuuum
+7 | | import λοοοοοοοοοοοοοονγ
+8 | | import μεδιυυυυυμ
+9 | | import looooooooooooooong
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+1   |-import loooooooooooooong
+2   |-import mediuuuuuum
+3 1 | import short
+4 2 | import σηορτ
+5 3 | import shoort
+6 4 | import mediuuuuum
+  5 |+import μεδιυυυυυμ
+  6 |+import mediuuuuuum
+  7 |+import loooooooooooooong
+7 8 | import λοοοοοοοοοοοοοονγ
+8   |-import μεδιυυυυυμ
+9 9 | import looooooooooooooong
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_straight_and_from_imports.py.snap

@@ -0,0 +1,26 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_straight_and_from_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / import mediuuuuuum
+2 | | import short
+3 | | import looooooooooooooooong
+4 | | from looooooooooooooong import a
+5 | | from mediuuuum import c
+6 | | from short import b
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+import short
+1 2 | import mediuuuuuum
+2   |-import short
+3 3 | import looooooooooooooooong
+4   |-from looooooooooooooong import a
+  4 |+from short import b
+5 5 | from mediuuuum import c
+6   |-from short import b
+  6 |+from looooooooooooooong import a
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_straight_imports.py.snap

@@ -0,0 +1,21 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_straight_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / import mediuuuuuumb
+2 | | import short
+3 | | import looooooooooooooooong
+4 | | import mediuuuuuuma
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+import short
+  2 |+import mediuuuuuuma
+1 3 | import mediuuuuuumb
+2   |-import short
+3 4 | import looooooooooooooooong
+4   |-import mediuuuuuuma
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort__length_sort_with_relative_imports.py.snap

@@ -0,0 +1,28 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_with_relative_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / from ..looooooooooooooong import a
+2 | | from ...mediuuuum import b
+3 | | from .short import c
+4 | | from ....short import c
+5 | | from . import d
+6 | | from .mediuuuum import a
+7 | | from ......short import b
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+1   |-from ..looooooooooooooong import a
+2   |-from ...mediuuuum import b
+  1 |+from . import d
+3 2 | from .short import c
+4 3 | from ....short import c
+5   |-from . import d
+6 4 | from .mediuuuum import a
+7 5 | from ......short import b
+  6 |+from ...mediuuuum import b
+  7 |+from ..looooooooooooooong import a
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort_straight__length_sort_from_imports.py.snap

@@ -0,0 +1,18 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_from_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / from mediuuuuuuuuuuum import a
+2 | | from short import b
+3 | | from loooooooooooooooooooooog import c
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+from loooooooooooooooooooooog import c
+1 2 | from mediuuuuuuuuuuum import a
+2 3 | from short import b
+3   |-from loooooooooooooooooooooog import c
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort_straight__length_sort_straight_and_from_imports.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_straight_and_from_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / import mediuuuuuum
+2 | | import short
+3 | | import looooooooooooooooong
+4 | | from looooooooooooooong import a
+5 | | from mediuuuum import c
+6 | | from short import b
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+import short
+1 2 | import mediuuuuuum
+2   |-import short
+3 3 | import looooooooooooooooong
+4 4 | from looooooooooooooong import a
+5 5 | from mediuuuum import c
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__length_sort_straight__length_sort_straight_imports.py.snap

@@ -0,0 +1,21 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+length_sort_straight_imports.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / import mediuuuuuumb
+2 | | import short
+3 | | import looooooooooooooooong
+4 | | import mediuuuuuuma
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+  1 |+import short
+  2 |+import mediuuuuuuma
+1 3 | import mediuuuuuumb
+2   |-import short
+3 4 | import looooooooooooooooong
+4   |-import mediuuuuuuma
+
+

crates/ruff_linter/src/rules/isort/sorting.rs

@@ -3,6 +3,7 @@
 use std::{borrow::Cow, cmp::Ordering, cmp::Reverse};
 
 use natord;
+use unicode_width::UnicodeWidthStr;
 
 use ruff_python_stdlib::str;
 
@@ -64,18 +65,27 @@ impl<'a> From<String> for NatOrdStr<'a> {
     }
 }
 
-#[derive(Debug, PartialOrd, Ord, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq)]
 pub(crate) enum Distance {
     Nearest(u32),
     Furthest(Reverse<u32>),
 }
 
+#[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq)]
+pub(crate) enum ImportStyle {
+    // Ex) `import foo`
+    Straight,
+    // Ex) `from foo import bar`
+    From,
+}
+
 /// A comparable key to capture the desired sorting order for an imported module (e.g.,
 /// `foo` in `from foo import bar`).
 #[derive(Debug, PartialOrd, Ord, PartialEq, Eq)]
 pub(crate) struct ModuleKey<'a> {
+    force_to_top: bool,
+    maybe_length: Option<usize>,
     distance: Distance,
-    force_to_top: Option<bool>,
     maybe_lowercase_name: Option<NatOrdStr<'a>>,
     module_name: Option<NatOrdStr<'a>>,
     first_alias: Option<MemberKey<'a>>,
@@ -88,26 +98,39 @@ impl<'a> ModuleKey<'a> {
         asname: Option<&'a str>,
         level: Option<u32>,
         first_alias: Option<(&'a str, Option<&'a str>)>,
+        style: ImportStyle,
         settings: &Settings,
     ) -> Self {
+        let level = level.unwrap_or_default();
+
+        let force_to_top = !name
+            .map(|name| settings.force_to_top.contains(name))
+            .unwrap_or_default(); // `false` < `true` so we get forced to top first
+
+        let maybe_length = (settings.length_sort
+            || (settings.length_sort_straight && style == ImportStyle::Straight))
+            .then_some(name.map(str::width).unwrap_or_default() + level as usize);
+
         let distance = match settings.relative_imports_order {
-            RelativeImportsOrder::ClosestToFurthest => Distance::Nearest(level.unwrap_or_default()),
+            RelativeImportsOrder::ClosestToFurthest => Distance::Nearest(level),
-            RelativeImportsOrder::FurthestToClosest => {
+            RelativeImportsOrder::FurthestToClosest => Distance::Furthest(Reverse(level)),
-                Distance::Furthest(Reverse(level.unwrap_or_default()))
-            }
         };
-        let force_to_top = name.map(|name| !settings.force_to_top.contains(name)); // `false` < `true` so we get forced to top first
+
         let maybe_lowercase_name = name.and_then(|name| {
             (!settings.case_sensitive).then_some(NatOrdStr(maybe_lowercase(name)))
         });
+
         let module_name = name.map(NatOrdStr::from);
+
         let asname = asname.map(NatOrdStr::from);
+
         let first_alias =
             first_alias.map(|(name, asname)| MemberKey::from_member(name, asname, settings));
 
         Self {
-            distance,
             force_to_top,
+            maybe_length,
+            distance,
             maybe_lowercase_name,
             module_name,
             first_alias,
@@ -122,6 +145,7 @@ impl<'a> ModuleKey<'a> {
 pub(crate) struct MemberKey<'a> {
     not_star_import: bool,
     member_type: Option<MemberType>,
+    maybe_length: Option<usize>,
     maybe_lowercase_name: Option<NatOrdStr<'a>>,
     module_name: NatOrdStr<'a>,
     asname: Option<NatOrdStr<'a>>,
@@ -133,6 +157,7 @@ impl<'a> MemberKey<'a> {
         let member_type = settings
             .order_by_type
             .then_some(member_type(name, settings));
+        let maybe_length = settings.length_sort.then_some(name.width());
         let maybe_lowercase_name =
             (!settings.case_sensitive).then_some(NatOrdStr(maybe_lowercase(name)));
         let module_name = NatOrdStr::from(name);
@@ -141,6 +166,7 @@ impl<'a> MemberKey<'a> {
         Self {
             not_star_import,
             member_type,
+            maybe_length,
             maybe_lowercase_name,
             module_name,
             asname,

crates/ruff_workspace/src/options.rs

@@ -2047,6 +2047,40 @@ pub struct IsortOptions {
     )]
     pub from_first: Option<bool>,
 
+    /// Sort imports by their string length, such that shorter imports appear
+    /// before longer imports. For example, by default, imports will be sorted
+    /// alphabetically, as in:
+    /// ```python
+    /// import collections
+    /// import os
+    /// ```
+    ///
+    /// Setting `length-sort = true` will instead sort such that shorter imports
+    /// appear before longer imports, as in:
+    /// ```python
+    /// import os
+    /// import collections
+    /// ```
+    #[option(
+        default = r#"false"#,
+        value_type = "bool",
+        example = r#"
+            length-sort = true
+        "#
+    )]
+    pub length_sort: Option<bool>,
+
+    /// Sort straight imports by their string length. Similar to `length-sort`,
+    /// but applies only to straight imports and doesn't affect `from` imports.
+    #[option(
+        default = r#"false"#,
+        value_type = "bool",
+        example = r#"
+            length-sort-straight = true
+        "#
+    )]
+    pub length_sort_straight: Option<bool>,
+
     // Tables are required to go last.
     /// A list of mappings from section names to modules.
     /// By default custom sections are output last, but this can be overridden with `section-order`.
@@ -2234,6 +2268,8 @@ impl IsortOptions {
             section_order,
             no_sections,
             from_first,
+            length_sort: self.length_sort.unwrap_or(false),
+            length_sort_straight: self.length_sort_straight.unwrap_or(false),
         })
     }
 }

ruff.schema.json

@@ -1477,6 +1477,20 @@
             "type": "string"
           }
         },
+        "length-sort": {
+          "description": "Sort imports by their string length, such that shorter imports appear before longer imports. For example, by default, imports will be sorted alphabetically, as in: ```python import collections import os ```\n\nSetting `length-sort = true` will instead sort such that shorter imports appear before longer imports, as in: ```python import os import collections ```",
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
+        "length-sort-straight": {
+          "description": "Sort straight imports by their string length. Similar to `length-sort`, but applies only to straight imports and doesn't affect `from` imports.",
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "lines-after-imports": {
           "description": "The number of blank lines to place after imports. Use `-1` for automatic determination.\n\nWhen using the formatter, only the values `-1`, `1`, and `2` are compatible because it enforces at least one empty and at most two empty lines after imports.",
           "type": [