Don't skip over imports and other nodes containing nested statements in import collector (#13521)

crates/ruff/tests/analyze_graph.rs

@@ -367,3 +367,58 @@ fn wildcard() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn nested_imports() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let root = ChildPath::new(tempdir.path());
+
+    root.child("ruff").child("__init__.py").write_str("")?;
+    root.child("ruff")
+        .child("a.py")
+        .write_str(indoc::indoc! {r#"
+        match x:
+            case 1:
+                import ruff.b
+    "#})?;
+    root.child("ruff")
+        .child("b.py")
+        .write_str(indoc::indoc! {r#"
+            try:
+                import ruff.c
+            except ImportError as e:
+                import ruff.d
+    "#})?;
+    root.child("ruff")
+        .child("c.py")
+        .write_str(indoc::indoc! {r#"def c(): ..."#})?;
+    root.child("ruff")
+        .child("d.py")
+        .write_str(indoc::indoc! {r#"def d(): ..."#})?;
+
+    insta::with_settings!({
+        filters => INSTA_FILTERS.to_vec(),
+    }, {
+        assert_cmd_snapshot!(command().current_dir(&root), @r#"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [
+            "ruff/c.py",
+            "ruff/d.py"
+          ],
+          "ruff/c.py": [],
+          "ruff/d.py": []
+        }
+
+        ----- stderr -----
+        "#);
+    });
+
+    Ok(())
+}

crates/ruff_graph/src/collector.rs

@@ -1,8 +1,8 @@
 use red_knot_python_semantic::ModuleName;
 use ruff_python_ast::visitor::source_order::{
-    walk_expr, walk_module, walk_stmt, SourceOrderVisitor, TraversalSignal,
+    walk_expr, walk_module, walk_stmt, SourceOrderVisitor,
 };
-use ruff_python_ast::{self as ast, AnyNodeRef, Expr, Mod, Stmt};
+use ruff_python_ast::{self as ast, Expr, Mod, Stmt};
 
 /// Collect all imports for a given Python file.
 #[derive(Default, Debug)]
@@ -32,28 +32,6 @@ impl<'a> Collector<'a> {
 }
 
 impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
-    fn enter_node(&mut self, node: AnyNodeRef<'ast>) -> TraversalSignal {
-        // If string detection is enabled, we have to visit everything. Otherwise, we should only
-        // visit compounds statements, which can contain import statements.
-        if self.string_imports
-            || matches!(
-                node,
-                AnyNodeRef::ModModule(_)
-                    | AnyNodeRef::StmtFunctionDef(_)
-                    | AnyNodeRef::StmtClassDef(_)
-                    | AnyNodeRef::StmtWhile(_)
-                    | AnyNodeRef::StmtFor(_)
-                    | AnyNodeRef::StmtWith(_)
-                    | AnyNodeRef::StmtIf(_)
-                    | AnyNodeRef::StmtTry(_)
-            )
-        {
-            TraversalSignal::Traverse
-        } else {
-            TraversalSignal::Skip
-        }
-    }
-
     fn visit_stmt(&mut self, stmt: &'ast Stmt) {
         match stmt {
             Stmt::ImportFrom(ast::StmtImportFrom {
@@ -107,9 +85,38 @@ impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
                     }
                 }
             }
-            _ => {
+            Stmt::FunctionDef(_)
+            | Stmt::ClassDef(_)
+            | Stmt::While(_)
+            | Stmt::If(_)
+            | Stmt::With(_)
+            | Stmt::Match(_)
+            | Stmt::Try(_)
+            | Stmt::For(_) => {
+                // Always traverse into compound statements.
                 walk_stmt(self, stmt);
             }
+
+            Stmt::Return(_)
+            | Stmt::Delete(_)
+            | Stmt::Assign(_)
+            | Stmt::AugAssign(_)
+            | Stmt::AnnAssign(_)
+            | Stmt::TypeAlias(_)
+            | Stmt::Raise(_)
+            | Stmt::Assert(_)
+            | Stmt::Global(_)
+            | Stmt::Nonlocal(_)
+            | Stmt::Expr(_)
+            | Stmt::Pass(_)
+            | Stmt::Break(_)
+            | Stmt::Continue(_)
+            | Stmt::IpyEscapeCommand(_) => {
+                // Only traverse simple statements when string imports is enabled.
+                if self.string_imports {
+                    walk_stmt(self, stmt);
+                }
+            }
         }
     }
 

crates/ruff_graph/src/lib.rs

@@ -1,13 +1,15 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+use anyhow::Result;
+
+use ruff_db::system::{SystemPath, SystemPathBuf};
+use ruff_python_ast::helpers::to_module_path;
+use ruff_python_parser::{parse, Mode};
+
 use crate::collector::Collector;
 pub use crate::db::ModuleDb;
 use crate::resolver::Resolver;
 pub use crate::settings::{AnalyzeSettings, Direction};
-use anyhow::Result;
-use ruff_db::system::{SystemPath, SystemPathBuf};
-use ruff_python_ast::helpers::to_module_path;
-use ruff_python_parser::{parse, Mode};
-use serde::{Deserialize, Serialize};
-use std::collections::{BTreeMap, BTreeSet};
 
 mod collector;
 mod db;
@@ -15,7 +17,7 @@ mod resolver;
 mod settings;
 
 #[derive(Debug, Default)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct ModuleImports(BTreeSet<SystemPathBuf>);
 
 impl ModuleImports {
@@ -90,7 +92,7 @@ impl ModuleImports {
 }
 
 #[derive(Debug, Default)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct ImportMap(BTreeMap<SystemPathBuf, ModuleImports>);
 
 impl ImportMap {