From b2d2796657b0682dcf3a7212bdfb6cfcc58059e4 Mon Sep 17 00:00:00 2001
From: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Date: Fri, 20 Feb 2026 05:27:57 +0300
Subject: [PATCH 1/3] raises: add missing | metacharacter to is_fully_escaped
 and unescape

The pipe character is a regex metacharacter (alternation operator)
but is_fully_escaped did not include it, so a match pattern like
'^foo|bar$' would be wrongly identified as a fully-escaped literal.
This causes rawmatch to be set incorrectly, leading to misleading
diff output on match failure.

Also add | to the unescape function's character class for
consistency.
---
 src/_pytest/raises.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/_pytest/raises.py b/src/_pytest/raises.py
index 7c246fde280..75eea7d8cc9 100644
--- a/src/_pytest/raises.py
+++ b/src/_pytest/raises.py
@@ -363,14 +363,14 @@ def _check_raw_type(
 
 def is_fully_escaped(s: str) -> bool:
     # we know we won't compile with re.VERBOSE, so whitespace doesn't need to be escaped
-    metacharacters = "{}()+.*?^$[]"
+    metacharacters = "{}()+.*?^$[]|"
     return not any(
         c in metacharacters and (i == 0 or s[i - 1] != "\\") for (i, c) in enumerate(s)
     )
 
 
 def unescape(s: str) -> str:
-    return re.sub(r"\\([{}()+-.*?^$\[\]\s\\])", r"\1", s)
+    return re.sub(r"\\([{}()+-.*?^$\[\]\s\\|])", r"\1", s)
 
 
 # These classes conceptually differ from ExceptionInfo in that ExceptionInfo is tied, and

From 9ef95be4ee9ab747667747ba9d6d33257e27dd48 Mon Sep 17 00:00:00 2001
From: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Date: Fri, 20 Feb 2026 15:43:36 +0300
Subject: [PATCH 2/3] Add regression test for pipe metacharacter in
 is_fully_escaped

Test that | is recognized as a regex metacharacter, not treated as a
literal. Also verify that unescape handles escaped pipes correctly.
---
 testing/python/raises.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/testing/python/raises.py b/testing/python/raises.py
index 6b2a765e7fb..7778f2caf08 100644
--- a/testing/python/raises.py
+++ b/testing/python/raises.py
@@ -430,3 +430,21 @@ def test_raises_match_compiled_regex(self) -> None:
         pattern_with_flags = re.compile(r"INVALID LITERAL", re.IGNORECASE)
         with pytest.raises(ValueError, match=pattern_with_flags):
             int("asdf")
+
+    def test_pipe_metacharacter_not_treated_as_literal(self) -> None:
+        """Regression test: | (pipe) must be recognized as a regex metacharacter.
+
+        When match='^foo|bar$' is used, is_fully_escaped should recognize this
+        as a real regex (not a fully-escaped literal), so that pytest does not
+        attempt an exact-string diff against it.
+        """
+        from _pytest.raises import is_fully_escaped, unescape
+
+        # Pipe is a metacharacter and should not be treated as escaped
+        assert not is_fully_escaped("foo|bar")
+
+        # Escaped pipe should be treated as a literal
+        assert is_fully_escaped(r"foo\|bar")
+
+        # unescape should remove the backslash from an escaped pipe
+        assert unescape(r"foo\|bar") == "foo|bar"

From 67f1959450e38045c36bf3e5c720f45e7ee4a265 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 12:44:06 +0000
Subject: [PATCH 3/3] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 testing/python/raises.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/testing/python/raises.py b/testing/python/raises.py
index 7778f2caf08..374a9d4882c 100644
--- a/testing/python/raises.py
+++ b/testing/python/raises.py
@@ -438,7 +438,8 @@ def test_pipe_metacharacter_not_treated_as_literal(self) -> None:
         as a real regex (not a fully-escaped literal), so that pytest does not
         attempt an exact-string diff against it.
         """
-        from _pytest.raises import is_fully_escaped, unescape
+        from _pytest.raises import is_fully_escaped
+        from _pytest.raises import unescape
 
         # Pipe is a metacharacter and should not be treated as escaped
         assert not is_fully_escaped("foo|bar")