From 52ed1759fb5c68bc7b667f23f9a5aaa44ea64bee Mon Sep 17 00:00:00 2001
From: Matt Clay <matt@mystile.com>
Date: Wed, 14 Jan 2026 16:39:49 -0800
Subject: [PATCH] Fix YAML string loading using Python loader

---
 changelogs/fragments/pyyaml-name.yml      |  2 ++
 lib/ansible/_internal/_yaml/_loader.py    | 17 +++++++++++++----
 test/integration/targets/pyyaml/runme.sh  | 10 ++++++++++
 test/integration/targets/pyyaml/runme.yml |  9 +++++++++
 4 files changed, 34 insertions(+), 4 deletions(-)
 create mode 100644 changelogs/fragments/pyyaml-name.yml
 create mode 100644 test/integration/targets/pyyaml/runme.yml

diff --git a/changelogs/fragments/pyyaml-name.yml b/changelogs/fragments/pyyaml-name.yml
new file mode 100644
index 00000000000..61dc2da0b28
--- /dev/null
+++ b/changelogs/fragments/pyyaml-name.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - yaml loading - Fix traceback when parsing YAML strings (not files) when using the pure Python implementation of PyYAML.
diff --git a/lib/ansible/_internal/_yaml/_loader.py b/lib/ansible/_internal/_yaml/_loader.py
index fa14006c0f8..226882d253d 100644
--- a/lib/ansible/_internal/_yaml/_loader.py
+++ b/lib/ansible/_internal/_yaml/_loader.py
@@ -13,22 +13,20 @@ from ._constructor import AnsibleConstructor, AnsibleInstrumentedConstructor
 if HAS_LIBYAML:
     from yaml.cyaml import CParser
 
-    class _YamlParser(CParser):
+    class _Parser(CParser):
         def __init__(self, stream: str | bytes | _io.IOBase) -> None:
             if isinstance(stream, (str, bytes)):
                 stream = AnsibleTagHelper.untag(stream)  # PyYAML + libyaml barfs on str/bytes subclasses
 
             CParser.__init__(self, stream)
 
-            self.name = getattr(stream, 'name', None)  # provide feature parity with the Python implementation (yaml.reader.Reader provides name)
-
 else:
     from yaml.composer import Composer
     from yaml.reader import Reader
     from yaml.scanner import Scanner
     from yaml.parser import Parser
 
-    class _YamlParser(Reader, Scanner, Parser, Composer):  # type: ignore[no-redef]
+    class _Parser(Reader, Scanner, Parser, Composer):  # type: ignore[no-redef]
         def __init__(self, stream: str | bytes | _io.IOBase) -> None:
             Reader.__init__(self, stream)
             Scanner.__init__(self)
@@ -36,6 +34,17 @@ else:
             Composer.__init__(self)
 
 
+class _YamlParser(_Parser):
+    def __init__(self, stream: str | bytes | _io.IOBase) -> None:
+        super().__init__(stream)
+
+        # The Python implementation of PyYAML (yaml.reader.Reader) provides self.name.
+        # However, it will fall back to "<...>" in various cases.
+        # The C implementation of PyYAML does not provide self.name.
+        # To provide consistency, name retrieval is re-implemented here.
+        self.name = getattr(stream, 'name', None)
+
+
 class AnsibleInstrumentedLoader(_YamlParser, AnsibleInstrumentedConstructor, Resolver):
     """Ansible YAML loader which supports Ansible custom behavior such as `Origin` tagging, but no Ansible-specific YAML tags."""
 
diff --git a/test/integration/targets/pyyaml/runme.sh b/test/integration/targets/pyyaml/runme.sh
index d08385d6092..a5c74da01a6 100755
--- a/test/integration/targets/pyyaml/runme.sh
+++ b/test/integration/targets/pyyaml/runme.sh
@@ -4,8 +4,18 @@ set -eu -o pipefail
 source virtualenv.sh
 set +x
 
+# Verify libyaml is in use.
+ansible --version | tee /dev/stderr | grep 'with libyaml'
+
+# Run tests with libyaml.
+ansible-playbook runme.yml "${@}"
+
 # deps are already installed, using --no-deps to avoid re-installing them
 # Install PyYAML without libyaml to validate ansible can run
 PYYAML_FORCE_LIBYAML=0 pip install --no-binary PyYAML --ignore-installed --no-cache-dir --no-deps PyYAML
 
+# Verify libyaml is not in use.
 ansible --version | tee /dev/stderr | grep 'without libyaml'
+
+# Run tests without libyaml.
+ansible-playbook runme.yml "${@}"
diff --git a/test/integration/targets/pyyaml/runme.yml b/test/integration/targets/pyyaml/runme.yml
new file mode 100644
index 00000000000..168d473dc56
--- /dev/null
+++ b/test/integration/targets/pyyaml/runme.yml
@@ -0,0 +1,9 @@
+- hosts: localhost
+  gather_facts: no
+  tasks:
+    - name: Read YAML from a string
+      assert:
+        that:
+          - "'1' | from_yaml == 1"
+          - "'[1]' | from_yaml == [1]"
+          - "'key: value' | from_yaml == {'key': 'value'}"