Fix ignoring conditional imports with ignore-imports=y

pylint/checkers/similar.py

@@ -59,6 +59,7 @@
 from astroid import nodes
 
 from pylint.checkers import BaseChecker, BaseRawFileChecker, table_lines_from_stats
+from pylint.checkers.utils import safe_infer
 from pylint.reporters.ureports.nodes import Section, Table
 from pylint.typing import MessageDefinitionTuple, Options
 from pylint.utils import LinterStats, decoding_stream
@@ -598,10 +599,18 @@ def stripped_lines(
     if ignore_imports or ignore_signatures:
         tree = astroid.parse("".join(lines))
     if ignore_imports:
-        node_is_import_by_lineno = (
-            (node.lineno, isinstance(node, (nodes.Import, nodes.ImportFrom)))
-            for node in tree.body
-        )
+
+        def _get_imports(root: list[nodes.NodeNG]) -> Iterable[tuple[int, bool]]:
+            """Find import nodes under given node."""
+            for node in root:
+                if isinstance(node, astroid.If) and isinstance(
+                    safe_infer(node.test), nodes.Const
+                ):
+                    # Check for imports in a body of a constant condition
+                    yield from _get_imports(node.body)
+                yield node.lineno, isinstance(node, (nodes.Import, nodes.ImportFrom))
+
+        node_is_import_by_lineno = _get_imports(tree.body)
         line_begins_import = {
             lineno: all(is_import for _, is_import in node_is_import_group)
             for lineno, node_is_import_group in groupby(

tests/regrtest_data/duplicate_code/ignore_conditional_imports/file_one.py

@@ -0,0 +1,5 @@
+import typing
+
+if typing.TYPE_CHECKING:
+    import os
+    import sys

tests/regrtest_data/duplicate_code/ignore_conditional_imports/file_two.py

@@ -0,0 +1,5 @@
+import typing
+
+if typing.TYPE_CHECKING:
+    import os
+    import sys

tests/test_similar.py

@@ -264,3 +264,11 @@ def test_useless_suppression() -> None:
             exit=False,
         )
         assert not runner.linter.stats.by_msg
+
+    def test_conditional_imports(self) -> None:
+        """Tests enabling ignore-imports with conditional imports works correctly."""
+        path = join(DATA, "ignore_conditional_imports")
+        self._runtest(
+            [path, "-e=duplicate-code", "-d=unused-import,C", "--ignore-imports=y"],
+            code=0,
+        )