chore: set recursion limit to 2000 for all platforms

.pre-commit-config.yaml

@@ -30,7 +30,7 @@ repos:
     hooks:
       - id: clang-format
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.1.1
+    rev: v0.1.3
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]

include/treespec.h

@@ -36,11 +36,7 @@ limitations under the License.
 namespace optree {
 
 // The maximum depth of a pytree.
-#ifdef _WIN32
 constexpr ssize_t MAX_RECURSION_DEPTH = 2000;
-#else
-constexpr ssize_t MAX_RECURSION_DEPTH = 5000;
-#endif
 
 // A PyTreeSpec describes the tree structure of a PyTree. A PyTree is a tree of Python values, where
 // the interior nodes are tuples, lists, dictionaries, or user-defined containers, and the leaves

optree/__init__.py

@@ -152,8 +152,12 @@
     'structseq_fields',
 ]
 
-MAX_RECURSION_DEPTH: int = MAX_RECURSION_DEPTH
-"""Maximum recursion depth for pytree traversal. It is 5000 on Unix-like systems and 2500 on Windows."""
+MAX_RECURSION_DEPTH: int = MAX_RECURSION_DEPTH  # 2000
+"""Maximum recursion depth for pytree traversal. It is 2000.
+
+This limit prevents infinite recursion from causing an overflow of the C stack
+and crashing Python.
+"""
 NONE_IS_NODE: bool = NONE_IS_NODE  # literal constant
 """Literal constant that treats :data:`None` as a pytree non-leaf node."""
 NONE_IS_LEAF: bool = NONE_IS_LEAF  # literal constant

optree/ops.py

@@ -96,8 +96,12 @@
     'prefix_errors',
 ]
 
-MAX_RECURSION_DEPTH: int = _C.MAX_RECURSION_DEPTH
-"""Maximum recursion depth for pytree traversal. It is 5000 on Unix-like systems and 2500 on Windows."""
+MAX_RECURSION_DEPTH: int = _C.MAX_RECURSION_DEPTH  # 2000
+"""Maximum recursion depth for pytree traversal. It is 2000.
+
+This limit prevents infinite recursion from causing an overflow of the C stack
+and crashing Python.
+"""
 NONE_IS_NODE: bool = False  # literal constant
 """Literal constant that treats :data:`None` as a pytree non-leaf node."""
 NONE_IS_LEAF: bool = True  # literal constant