flake8-type-checking: Always recognise relative imports as first-party (#12994)

crates/ruff_linter/src/rules/flake8_type_checking/rules/typing_only_runtime_import.rs

@@ -300,7 +300,7 @@ pub(crate) fn typing_only_runtime_import(
             // Categorize the import, using coarse-grained categorization.
             let import_type = match categorize(
                 &qualified_name.to_string(),
-                0,
+                qualified_name.is_unresolved_import(),
                 &checker.settings.src,
                 checker.package(),
                 checker.settings.isort.detect_same_package,

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

@@ -91,7 +91,7 @@ enum Reason<'a> {
 #[allow(clippy::too_many_arguments)]
 pub(crate) fn categorize<'a>(
     module_name: &str,
-    level: u32,
+    is_relative: bool,
     src: &[PathBuf],
     package: Option<&Path>,
     detect_same_package: bool,
@@ -103,14 +103,14 @@ pub(crate) fn categorize<'a>(
 ) -> &'a ImportSection {
     let module_base = module_name.split('.').next().unwrap();
     let (mut import_type, mut reason) = {
-        if level == 0 && module_base == "__future__" {
+        if !is_relative && module_base == "__future__" {
             (&ImportSection::Known(ImportType::Future), Reason::Future)
         } else if no_sections {
             (
                 &ImportSection::Known(ImportType::FirstParty),
                 Reason::NoSections,
             )
-        } else if level > 0 {
+        } else if is_relative {
             (
                 &ImportSection::Known(ImportType::LocalFolder),
                 Reason::NonZeroLevel,
@@ -132,7 +132,7 @@ pub(crate) fn categorize<'a>(
                 &ImportSection::Known(ImportType::FirstParty),
                 Reason::SourceMatch(src),
             )
-        } else if level == 0 && module_name == "__main__" {
+        } else if !is_relative && module_name == "__main__" {
             (
                 &ImportSection::Known(ImportType::FirstParty),
                 Reason::KnownFirstParty,
@@ -190,7 +190,7 @@ pub(crate) fn categorize_imports<'a>(
     for (alias, comments) in block.import {
         let import_type = categorize(
             &alias.module_name(),
-            0,
+            false,
             src,
             package,
             detect_same_package,
@@ -210,7 +210,7 @@ pub(crate) fn categorize_imports<'a>(
     for (import_from, aliases) in block.import_from {
         let classification = categorize(
             &import_from.module_name(),
-            import_from.level,
+            import_from.level > 0,
             src,
             package,
             detect_same_package,
@@ -230,7 +230,7 @@ pub(crate) fn categorize_imports<'a>(
     for ((import_from, alias), aliases) in block.import_from_as {
         let classification = categorize(
             &import_from.module_name(),
-            import_from.level,
+            import_from.level > 0,
             src,
             package,
             detect_same_package,
@@ -250,7 +250,7 @@ pub(crate) fn categorize_imports<'a>(
     for (import_from, comments) in block.import_from_star {
         let classification = categorize(
             &import_from.module_name(),
-            import_from.level,
+            import_from.level > 0,
             src,
             package,
             detect_same_package,

crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs

@@ -6,8 +6,7 @@ use std::collections::BTreeMap;
 
 use ruff_diagnostics::{Applicability, Diagnostic, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast as ast;
+use ruff_python_ast::{self as ast, Stmt};
-use ruff_python_ast::{Stmt, StmtImportFrom};
 use ruff_python_semantic::{
     AnyImport, BindingKind, Exceptions, Imported, NodeId, Scope, SemanticModel, SubmoduleImport,
 };
@@ -218,10 +217,11 @@ enum UnusedImportContext {
     Other,
 }
 
-fn is_first_party(qualified_name: &str, level: u32, checker: &Checker) -> bool {
+fn is_first_party(import: &AnyImport, checker: &Checker) -> bool {
+    let qualified_name = import.qualified_name();
     let category = isort::categorize(
-        qualified_name,
+        &qualified_name.to_string(),
-        level,
+        qualified_name.is_unresolved_import(),
         &checker.settings.src,
         checker.package(),
         checker.settings.isort.detect_same_package,
@@ -343,13 +343,6 @@ pub(crate) fn unused_import(checker: &Checker, scope: &Scope, diagnostics: &mut
         let in_except_handler =
             exceptions.intersects(Exceptions::MODULE_NOT_FOUND_ERROR | Exceptions::IMPORT_ERROR);
         let multiple = bindings.len() > 1;
-        let level = match checker.semantic().statement(import_statement) {
-            Stmt::Import(_) => 0,
-            Stmt::ImportFrom(StmtImportFrom { level, .. }) => *level,
-            _ => {
-                continue;
-            }
-        };
 
         // pair each binding with context; divide them by how we want to fix them
         let (to_reexport, to_remove): (Vec<_>, Vec<_>) = bindings
@@ -357,9 +350,7 @@ pub(crate) fn unused_import(checker: &Checker, scope: &Scope, diagnostics: &mut
             .map(|binding| {
                 let context = if in_except_handler {
                     UnusedImportContext::ExceptHandler
-                } else if in_init
+                } else if in_init && is_first_party(&binding.import, checker) {
-                    && is_first_party(&binding.import.qualified_name().to_string(), level, checker)
-                {
                     UnusedImportContext::DunderInitFirstParty {
                         dunder_all_count: DunderAllCount::from(dunder_all_exprs.len()),
                         submodule_import: binding.import.is_submodule_import(),