From 329740e8057d184c0f35e51a17413ac7306579a8 Mon Sep 17 00:00:00 2001
From: Friday <aifriday700@gmail.com>
Date: Wed, 18 Feb 2026 00:33:10 +0000
Subject: [PATCH 1/2] Fix capteesys producing doubled output with --capture=no

When capteesys is used with -s (--capture=no), output was printed
twice: once by TeeCaptureIO teeing to the original stream in
real-time, and again by pop_outerr_to_orig() writing the buffered
content back via writeorg() on close.

Skip the writeorg() call when tee is enabled, since the output was
already delivered live.

Fixes #13784.
---
 changelog/13784.bugfix.rst |  1 +
 src/_pytest/capture.py     |  9 ++++++++-
 testing/test_capture.py    | 20 ++++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 changelog/13784.bugfix.rst

diff --git a/changelog/13784.bugfix.rst b/changelog/13784.bugfix.rst
new file mode 100644
index 00000000000..a2f4cf54327
--- /dev/null
+++ b/changelog/13784.bugfix.rst
@@ -0,0 +1 @@
+Fixed ``capteesys`` producing doubled output when used with ``--capture=no`` (``-s``).
diff --git a/src/_pytest/capture.py b/src/_pytest/capture.py
index 6d98676be5f..f9f8f9e4a28 100644
--- a/src/_pytest/capture.py
+++ b/src/_pytest/capture.py
@@ -944,7 +944,14 @@ def _start(self) -> None:
 
     def close(self) -> None:
         if self._capture is not None:
-            out, err = self._capture.pop_outerr_to_orig()
+            if self._config.get("tee"):
+                # When tee is enabled, output was already written to the
+                # original stream in real-time by TeeCaptureIO.  Using
+                # pop_outerr_to_orig() would write it a second time via
+                # writeorg(), causing doubled output (see #13784).
+                out, err = self._capture.readouterr()
+            else:
+                out, err = self._capture.pop_outerr_to_orig()
             self._captured_out += out
             self._captured_err += err
             self._capture.stop_capturing()
diff --git a/testing/test_capture.py b/testing/test_capture.py
index 11fd18f08ff..45ab1e05e5f 100644
--- a/testing/test_capture.py
+++ b/testing/test_capture.py
@@ -478,6 +478,26 @@ def test_one(capteesys):
         result.stdout.fnmatch_lines(["sTdoUt", "sTdeRr"])  # no tee, just reported
         assert not result.stderr.lines
 
+    def test_capteesys_no_double_output_with_capture_no(
+        self, pytester: Pytester
+    ) -> None:
+        """capteesys with --capture=no should not produce doubled output (#13784)."""
+        p = pytester.makepyfile(
+            """\
+            def test_one(capteesys):
+                print("hello world stdout")
+                out, err = capteesys.readouterr()
+                assert out == "hello world stdout\\n"
+            """
+        )
+        result = pytester.runpytest(p, "--quiet", "--quiet", "-rN", "-s")
+        assert result.ret == ExitCode.OK
+        # "hello world stdout" should appear exactly once, not twice.
+        count = result.stdout.lines.count("hello world stdout")
+        assert count == 1, (
+            f"Expected 'hello world stdout' once, but found {count} times"
+        )
+
     def test_capsyscapfd(self, pytester: Pytester) -> None:
         p = pytester.makepyfile(
             """\

From f577edc8daa3b1f18ec54f348c4f34b3799e8e43 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 18 Feb 2026 00:33:48 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 testing/test_capture.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testing/test_capture.py b/testing/test_capture.py
index 45ab1e05e5f..3083d2d7a37 100644
--- a/testing/test_capture.py
+++ b/testing/test_capture.py
@@ -481,7 +481,7 @@ def test_one(capteesys):
     def test_capteesys_no_double_output_with_capture_no(
         self, pytester: Pytester
     ) -> None:
-        """capteesys with --capture=no should not produce doubled output (#13784)."""
+        """Capteesys with --capture=no should not produce doubled output (#13784)."""
         p = pytester.makepyfile(
             """\
             def test_one(capteesys):