From 4d3d7f47ebce9ee27d6ae87c34c8941c438cf353 Mon Sep 17 00:00:00 2001
From: wyattscarpenter <wyattscarpenter@gmail.com>
Date: Thu, 23 Oct 2025 21:17:35 -0700
Subject: [PATCH 1/2] add failing test
 testReportCoberturaCrashOnNamespacePackages

---
 test-data/unit/reports.test | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/test-data/unit/reports.test b/test-data/unit/reports.test
index 82c3869bb855..714610314c88 100644
--- a/test-data/unit/reports.test
+++ b/test-data/unit/reports.test
@@ -547,3 +547,37 @@ namespace_packages = True
 </table>
 </body>
 </html>
+
+[case testReportCoberturaCrashOnNamespacePackages]
+# cmd: mypy --cobertura-xml-report report -p folder
+-- Regression test for https://github.com/python/mypy/issues/19843
+[file folder/subfolder/something.py]
+-- This output is not important, but due to the way tests are run we need to check it.
+[outfile report/cobertura.xml]
+<coverage timestamp="$TIMESTAMP" version="$VERSION" line-rate="1.0" branch-rate="0" lines-covered="0" lines-valid="0">
+  <sources>
+    <source>$PWD</source>
+  </sources>
+  <packages>
+    <package complexity="1.0" name="folder" branch-rate="0" line-rate="1.0">
+      <classes>
+        <class complexity="1.0" filename="folder" name="folder" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+        <class complexity="1.0" filename="folder/subfolder" name="subfolder" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+      </classes>
+    </package>
+    <package complexity="1.0" name="folder.subfolder" branch-rate="0" line-rate="1.0">
+      <classes>
+        <class complexity="1.0" filename="folder/subfolder/something.py" name="something.py" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+      </classes>
+    </package>
+  </packages>
+</coverage>

From a33382200b9cb2d5b4a0eb19fce3b0266aa73d5d Mon Sep 17 00:00:00 2001
From: wyattscarpenter <wyattscarpenter@gmail.com>
Date: Thu, 23 Oct 2025 21:18:52 -0700
Subject: [PATCH 2/2] Fix for windows.

---
 mypy/report.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mypy/report.py b/mypy/report.py
index 39cd80ed38bf..90a62c8a4c7c 100644
--- a/mypy/report.py
+++ b/mypy/report.py
@@ -141,12 +141,9 @@ def should_skip_path(path: str) -> bool:
 
 def iterate_python_lines(path: str) -> Iterator[tuple[int, str]]:
     """Return an iterator over (line number, line text) from a Python file."""
-    try:
+    if not os.path.isdir(path):  # can happen with namespace packages
         with tokenize.open(path) as input_file:
             yield from enumerate(input_file, 1)
-    except IsADirectoryError:
-        # can happen with namespace packages
-        pass
 
 
 class FuncCounterVisitor(TraverserVisitor):