From d69ddeda1d5ad190e9b9e8c171241bf22df1b595 Mon Sep 17 00:00:00 2001
From: wyattscarpenter <wyattscarpenter@gmail.com>
Date: Wed, 1 Oct 2025 19:31:18 -0700
Subject: [PATCH 1/3] add failing test,
 testReportIsADirectoryErrorCrashOnNamespacePackages

A regression test for the internal crash https://github.com/python/mypy/issues/18128.
---
 test-data/unit/reports.test | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/test-data/unit/reports.test b/test-data/unit/reports.test
index 82c3869bb855..871ebc4c6184 100644
--- a/test-data/unit/reports.test
+++ b/test-data/unit/reports.test
@@ -547,3 +547,11 @@ namespace_packages = True
 </table>
 </body>
 </html>
+
+[case testReportIsADirectoryErrorCrashOnNamespacePackages]
+# cmd: mypy --linecoverage-report report -p folder
+--Regression test for https://github.com/python/mypy/issues/18128
+-- "IsADirectoryError for namespace packages when using --linecoverage-report"
+[file folder/subfolder/something.py]
+class Something:
+    pass

From 6d916744df5015e325648128054bbc1bbf065bb6 Mon Sep 17 00:00:00 2001
From: wyattscarpenter <wyattscarpenter@gmail.com>
Date: Thu, 23 Oct 2025 18:05:53 -0700
Subject: [PATCH 2/3] fix that prevents crash

---
 mypy/report.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mypy/report.py b/mypy/report.py
index 39cd80ed38bf..09a59f8a6f2c 100644
--- a/mypy/report.py
+++ b/mypy/report.py
@@ -424,6 +424,9 @@ def on_file(
         type_map: dict[Expression, Type],
         options: Options,
     ) -> None:
+        if os.path.isdir(tree.path):  # can happen with namespace packages
+            return
+
         with open(tree.path) as f:
             tree_source = f.readlines()
 

From ff48189028949ffee70919079ac93f1233e099ca Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 27 Oct 2025 16:45:14 +0000
Subject: [PATCH 3/3] Fix comment formatting in a test

---
 test-data/unit/reports.test | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-data/unit/reports.test b/test-data/unit/reports.test
index 871ebc4c6184..dab9c2a379c1 100644
--- a/test-data/unit/reports.test
+++ b/test-data/unit/reports.test
@@ -550,7 +550,7 @@ namespace_packages = True
 
 [case testReportIsADirectoryErrorCrashOnNamespacePackages]
 # cmd: mypy --linecoverage-report report -p folder
---Regression test for https://github.com/python/mypy/issues/18128
+-- Regression test for https://github.com/python/mypy/issues/18128
 -- "IsADirectoryError for namespace packages when using --linecoverage-report"
 [file folder/subfolder/something.py]
 class Something: