[pyupgrade] Prevent infinite loop with I002 and UP026 (#20634)

## Summary
Closes #20601

Do not treat imports as unused for the rule [unnecessary-builtin-import
(UP029)](https://docs.astral.sh/ruff/rules/unnecessary-builtin-import/)
if they are required by
`isort`([missing-required-import](https://docs.astral.sh/ruff/rules/missing-required-import/))

## Test Plan
- Added test case `i002_up029_conflict` to ensure there is no conflict

Co-authored-by: Igor Drokin <drokinii1017@gmail.com>

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP029_1.py

@@ -0,0 +1 @@
+from builtins import str, int

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

@@ -97,7 +97,7 @@ mod tests {
     )]
     #[test_case(Rule::UTF8EncodingDeclaration, Path::new("UP009_many_empty_lines.py"))]
     #[test_case(Rule::UnicodeKindPrefix, Path::new("UP025.py"))]
-    #[test_case(Rule::UnnecessaryBuiltinImport, Path::new("UP029.py"))]
+    #[test_case(Rule::UnnecessaryBuiltinImport, Path::new("UP029_0.py"))]
     #[test_case(Rule::UnnecessaryClassParentheses, Path::new("UP039.py"))]
     #[test_case(Rule::UnnecessaryDefaultTypeArgs, Path::new("UP043.py"))]
     #[test_case(Rule::UnnecessaryEncodeUTF8, Path::new("UP012.py"))]
@@ -357,6 +357,32 @@ mod tests {
         ");
     }
 
+    #[test_case(Path::new("UP029_1.py"))]
+    fn i002_up029_conflict(path: &Path) -> Result<()> {
+        let snapshot = format!("{}_skip_required_imports", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("pyupgrade").join(path).as_path(),
+            &settings::LinterSettings {
+                isort: isort::settings::Settings {
+                    required_imports: BTreeSet::from_iter([
+                        // https://github.com/astral-sh/ruff/issues/20601
+                        NameImport::ImportFrom(MemberNameImport::member(
+                            "builtins".to_string(),
+                            "str".to_string(),
+                        )),
+                    ]),
+                    ..Default::default()
+                },
+                ..settings::LinterSettings::for_rules([
+                    Rule::MissingRequiredImport,
+                    Rule::UnnecessaryBuiltinImport,
+                ])
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
+
     #[test]
     fn unnecessary_default_type_args_stubs_py312_preview() -> Result<()> {
         let snapshot = format!("{}__preview", "UP043.pyi");

crates/ruff_linter/src/rules/pyupgrade/rules/unnecessary_builtin_import.rs

@@ -6,6 +6,7 @@ use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::fix;
+use crate::rules::pyupgrade::rules::is_import_required_by_isort;
 use crate::{AlwaysFixableViolation, Fix};
 
 /// ## What it does
@@ -85,6 +86,13 @@ pub(crate) fn unnecessary_builtin_import(
     // Identify unaliased, builtin imports.
     let unused_imports: Vec<&Alias> = names
         .iter()
+        .filter(|alias| {
+            !is_import_required_by_isort(
+                &checker.settings().isort.required_imports,
+                stmt.into(),
+                alias,
+            )
+        })
         .filter(|alias| alias.asname.is_none())
         .filter(|alias| {
             matches!(

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP029_0.py.snap

@@ -2,7 +2,7 @@
 source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
 ---
 UP029 [*] Unnecessary builtin import: `*`
- --> UP029.py:1:1
+ --> UP029_0.py:1:1
   |
 1 | from builtins import *
   | ^^^^^^^^^^^^^^^^^^^^^^
@@ -17,7 +17,7 @@ help: Remove unnecessary builtin import
 note: This is an unsafe fix and may change runtime behavior
 
 UP029 [*] Unnecessary builtin imports: `ascii`, `bytes`
- --> UP029.py:2:1
+ --> UP029_0.py:2:1
   |
 1 | from builtins import *
 2 | from builtins import ascii, bytes, compile
@@ -35,7 +35,7 @@ help: Remove unnecessary builtin import
 note: This is an unsafe fix and may change runtime behavior
 
 UP029 [*] Unnecessary builtin imports: `filter`, `zip`
- --> UP029.py:4:1
+ --> UP029_0.py:4:1
   |
 2 | from builtins import ascii, bytes, compile
 3 | from builtins import str as _str
@@ -56,7 +56,7 @@ help: Remove unnecessary builtin import
 note: This is an unsafe fix and may change runtime behavior
 
 UP029 [*] Unnecessary builtin import: `open`
- --> UP029.py:5:1
+ --> UP029_0.py:5:1
   |
 3 | from builtins import str as _str
 4 | from six.moves import filter, zip, zip_longest

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP029_1.py_skip_required_imports.snap

@@ -0,0 +1,13 @@
+---
+source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
+---
+UP029 [*] Unnecessary builtin import: `int`
+ --> UP029_1.py:1:1
+  |
+1 | from builtins import str, int
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+help: Remove unnecessary builtin import
+  - from builtins import str, int
+1 + from builtins import str
+note: This is an unsafe fix and may change runtime behavior