deprecate: add PytestRemovedIn10Warning for baseid/nodeid string parameters

Add deprecation warnings for using string-based fixture scoping:
- FixtureDef baseid parameter: use node parameter instead
- _register_fixture nodeid parameter: use node parameter instead
- parsefactories nodeid string: use holder/node API instead

The warnings only trigger when a non-empty nodeid string is passed
without a node. Global plugins (nodeid=None) and synthetic fixtures
(baseid='') do not trigger warnings.

These will be removed in pytest 10, completing the migration to
node-based fixture scoping.

Co-authored-by: Cursor AI <ai@cursor.sh>
Co-authored-by: Anthropic Claude Opus 4 <claude@anthropic.com>

Author: 3 people

src/_pytest/fixtures.py

@@ -67,6 +67,7 @@
 from _pytest.scope import _ScopeName
 from _pytest.scope import HIGH_SCOPES
 from _pytest.scope import Scope
+from _pytest.warning_types import PytestRemovedIn10Warning
 from _pytest.warning_types import PytestWarning
 
 
@@ -975,6 +976,15 @@ def __init__(
         node: nodes.Node | None = None,
     ) -> None:
         check_ispytest(_ispytest)
+        # Emit deprecation warning if baseid string is used when node could be provided.
+        # baseid=None (global plugins) and baseid="" (synthetic fixtures) are fine.
+        if baseid and node is None:
+            warnings.warn(
+                "Passing baseid to FixtureDef is deprecated. "
+                "Pass node instead for fixture scoping.",
+                PytestRemovedIn10Warning,
+                stacklevel=2,
+            )
         # The node where this fixture was defined, if available.
         # Used for node-based matching which is more robust than string matching.
         self.node: Final = node
@@ -1799,7 +1809,7 @@ def _register_fixture(
         :param func:
             The fixture's implementation function.
         :param nodeid:
-            The visibility of the fixture (legacy, prefer node).
+            The visibility of the fixture (deprecated, use node instead).
             The fixture will be available to the node with this nodeid and
             its children in the collection tree. None means global visibility.
         :param node:
@@ -1814,6 +1824,15 @@ def _register_fixture(
         :param autouse:
             Whether this is an autouse fixture.
         """
+        # Emit deprecation warning if nodeid string is used when node could be provided.
+        # nodeid=None (global plugins) is fine.
+        if nodeid and node is None:
+            warnings.warn(
+                "Passing nodeid to _register_fixture is deprecated. "
+                "Pass node instead for fixture scoping.",
+                PytestRemovedIn10Warning,
+                stacklevel=2,
+            )
         fixture_def = FixtureDef(
             config=self.config,
             baseid=nodeid if node is None else None,
@@ -1901,6 +1920,14 @@ def parsefactories(
             raise TypeError("parsefactories() requires holder or node_or_obj")
         elif nodeid is not NOTSET:
             # Legacy: parsefactories(obj, nodeid) - string-based scoping only
+            # Only warn if a non-None nodeid string is passed (None means global plugin)
+            if nodeid is not None:
+                warnings.warn(
+                    "Passing nodeid string to parsefactories is deprecated. "
+                    "Use parsefactories(holder=obj, node=node) instead.",
+                    PytestRemovedIn10Warning,
+                    stacklevel=2,
+                )
             holderobj = node_or_obj
             effective_nodeid = nodeid
         else: