fix(dev-python): hand requires-python to the remote script with a valid backreference

76adaeb9e8 wrote the regex_search group reference as '\1' inside the folded
task scalar. Jinja unescapes string literals, so the filter received \x01,
rejected it as an unknown argument and failed the dev-python task on every
remote host. The literal is now '\\1', and the unit test renders the task's
environment expression the way Ansible does instead of only checking that
the variable is named.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

roles/dev-python/tasks/00_core.yml

@@ -10,7 +10,7 @@
     SKIP_DOCKER_APT_SANITIZER: "1"
     INFINITO_PYTHON_REQUIRES: >-
       {{ lookup('file', lookup('path_absolute', 'pyproject.toml'))
-         | regex_search('(?m)^requires-python\s*=\s*"([^"]+)"', '\1')
+         | regex_search('(?m)^requires-python\\s*=\\s*"([^"]+)"', '\\1')
          | first }}
   become: true
 

tests/unit/python/roles/dev-python/files/test_install.py

@@ -6,7 +6,11 @@ import tomllib
 import unittest
 from pathlib import Path
 
+import jinja2
+from ansible.plugins.filter.core import regex_search
+
 from utils.cache.files import PROJECT_ROOT, read_text
+from utils.cache.yaml import load_yaml_str
 
 SCRIPT = PROJECT_ROOT / "roles/dev-python/files/shell/install.sh"
 ROLE_TASKS = PROJECT_ROOT / "roles/dev-python/tasks/00_core.yml"
@@ -199,7 +203,30 @@ class TestBoundsFromRequiresPython(unittest.TestCase):
             requires=">=3.12,<3.14",
         )
         self.assertEqual(result.stdout, "12 13")
-        self.assertIn("INFINITO_PYTHON_REQUIRES", read_text(str(ROLE_TASKS)))
+
+    def test_the_role_renders_requires_python_from_pyproject(self) -> None:
+        task = next(
+            task
+            for task in load_yaml_str(read_text(str(ROLE_TASKS)))
+            if "ansible.builtin.script" in task
+        )
+        expression = task["environment"]["INFINITO_PYTHON_REQUIRES"]
+
+        def lookup(name: str, term: str) -> str:
+            return {
+                "path_absolute": lambda: str(PROJECT_ROOT / term),
+                "file": lambda: read_text(term),
+            }[name]()
+
+        environment = jinja2.Environment(
+            autoescape=jinja2.select_autoescape(default_for_string=False)
+        )
+        environment.filters["regex_search"] = regex_search
+        environment.globals["lookup"] = lookup
+        spec = tomllib.loads(read_text(str(PROJECT_ROOT / "pyproject.toml")))[
+            "project"
+        ]["requires-python"]
+        self.assertEqual(environment.from_string(expression).render(), spec)
 
     def test_an_unsupported_requires_python_form_fails_loudly(self) -> None:
         result = _call("true", requires=">=3.11")