add support for CP + torch SDPA

tests/loaders/test_patch_manager_cp.py

@@ -0,0 +1,74 @@
+"""Tests for PatchManager context parallel patch selection."""
+
+import addict
+
+from axolotl.loaders.patch_manager import PatchManager
+from axolotl.utils.dict import DictDefault
+
+
+def _stub_transformers_patches(monkeypatch):
+    """Replace trainer loss patchers with no-ops for isolation."""
+    monkeypatch.setattr(
+        "axolotl.monkeypatch.transformers.trainer_loss_calc.patch_evaluation_loop",
+        lambda: None,
+    )
+    monkeypatch.setattr(
+        "axolotl.monkeypatch.transformers.trainer_loss_calc.patch_maybe_log_save_evaluate",
+        lambda: None,
+    )
+
+
+def test_patch_manager_applies_flash_cp_patch(monkeypatch):
+    """When flash attention is enabled, we patch Trainer for CP."""
+    _stub_transformers_patches(monkeypatch)
+
+    patch_calls = {"count": 0}
+
+    def stub_patch():
+        patch_calls["count"] += 1
+
+    monkeypatch.setattr(
+        "axolotl.monkeypatch.transformers.trainer_context_parallel.patch_prepare_context_parallel_inputs",
+        stub_patch,
+    )
+
+    cfg = DictDefault(
+        {
+            "context_parallel_size": 2,
+            "flash_attention": True,
+            "sdp_attention": False,
+        }
+    )
+
+    manager = PatchManager(cfg, addict.Dict())
+    manager._apply_transformers_patches()
+
+    assert patch_calls["count"] == 1
+
+
+def test_patch_manager_skips_flash_patch_for_sdpa(monkeypatch):
+    """When only SDPA is requested, we should not patch Trainer."""
+    _stub_transformers_patches(monkeypatch)
+
+    patch_calls = {"count": 0}
+
+    def stub_patch():
+        patch_calls["count"] += 1
+
+    monkeypatch.setattr(
+        "axolotl.monkeypatch.transformers.trainer_context_parallel.patch_prepare_context_parallel_inputs",
+        stub_patch,
+    )
+
+    cfg = DictDefault(
+        {
+            "context_parallel_size": 2,
+            "flash_attention": False,
+            "sdp_attention": True,
+        }
+    )
+
+    manager = PatchManager(cfg, addict.Dict())
+    manager._apply_transformers_patches()
+
+    assert patch_calls["count"] == 0