Fix nested if statement dispatch not recognized (#294)

src/unimport/analyzers/import_statement.py

@@ -103,6 +103,18 @@ def _is_type_checking_block(if_node: ast.If) -> bool:
             return True
         return False
 
+    @staticmethod
+    def _collect_import_names(nodes: list[ast.stmt], *, recursive: bool = True) -> set[str]:
+        names: set[str] = set()
+        for node in nodes:
+            if isinstance(node, (ast.Import, ast.ImportFrom)):
+                for alias in node.names:
+                    names.add(alias.asname or alias.name)
+            elif recursive and isinstance(node, ast.If):
+                names |= ImportAnalyzer._collect_import_names(node.body)
+                names |= ImportAnalyzer._collect_import_names(node.orelse)
+        return names
+
     def visit_If(self, if_node: ast.If) -> None:
         if self._is_type_checking_block(if_node):
             self._in_type_checking = True
@@ -113,17 +125,9 @@ def visit_If(self, if_node: ast.If) -> None:
                 self.visit(node)
             return
 
-        self.if_names = {
-            name.asname or name.name
-            for n in filter(lambda node: isinstance(node, (ast.Import, ast.ImportFrom)), if_node.body)
-            for name in n.names  # type: ignore
-        }
-
-        self.orelse_names = {
-            name.asname or name.name
-            for n in filter(lambda node: isinstance(node, (ast.Import, ast.ImportFrom)), if_node.orelse)
-            for name in n.names  # type: ignore
-        }
+        self.if_names = self._collect_import_names(if_node.body)
+
+        self.orelse_names = self._collect_import_names(if_node.orelse, recursive=False)
 
         self.generic_visit(if_node)
 

tests/cases/analyzer/if_dispatch/case_7.py

@@ -0,0 +1,23 @@
+from typing import Union
+
+from unimport.statement import Import, ImportFrom, Name
+
+__all__ = ["NAMES", "IMPORTS", "UNUSED_IMPORTS"]
+
+
+NAMES: list[Name] = [
+    Name(lineno=4, name="sys.version_info", is_all=False),
+    Name(lineno=5, name="TYPE_CHECKING", is_all=False),
+    Name(lineno=8, name="Any", is_all=False),
+    Name(lineno=11, name="Any", is_all=False),
+    Name(lineno=11, name="Any", is_all=False),
+    Name(lineno=11, name="Any", is_all=False),
+    Name(lineno=19, name="print", is_all=False),
+    Name(lineno=19, name="ForwardRef", is_all=False),
+]
+IMPORTS: list[Union[Import, ImportFrom]] = [
+    Import(lineno=1, column=1, name="sys", package="sys"),
+    ImportFrom(lineno=2, column=1, name="TYPE_CHECKING", package="typing", star=False, suggestions=[]),
+    ImportFrom(lineno=2, column=2, name="Any", package="typing", star=False, suggestions=[]),
+]
+UNUSED_IMPORTS: list[Union[Import, ImportFrom]] = []

tests/cases/refactor/if_dispatch/case_7.py

@@ -0,0 +1,19 @@
+import sys
+from typing import TYPE_CHECKING, Any
+
+if sys.version_info < (3, 7):
+    if TYPE_CHECKING:
+
+        class ForwardRef:
+            def __init__(self, arg: Any):
+                pass
+
+            def _eval_type(self, globalns: Any, localns: Any) -> Any:
+                pass
+
+    else:
+        from typing import _ForwardRef as ForwardRef
+else:
+    from typing import ForwardRef
+
+print(ForwardRef)

tests/cases/source/if_dispatch/case_7.py

@@ -0,0 +1,19 @@
+import sys
+from typing import TYPE_CHECKING, Any
+
+if sys.version_info < (3, 7):
+    if TYPE_CHECKING:
+
+        class ForwardRef:
+            def __init__(self, arg: Any):
+                pass
+
+            def _eval_type(self, globalns: Any, localns: Any) -> Any:
+                pass
+
+    else:
+        from typing import _ForwardRef as ForwardRef
+else:
+    from typing import ForwardRef
+
+print(ForwardRef)