fix duplicate attn_implementation in gpt-oss yamls and flaky caplog tests

examples/gpt-oss/gpt-oss-120b-fft-fsdp2-offload.yaml

@@ -47,7 +47,6 @@ learning_rate: 2e-5
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

examples/gpt-oss/gpt-oss-20b-fft-deepspeed-zero3.yaml

@@ -43,7 +43,6 @@ learning_rate: 2e-5
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

examples/gpt-oss/gpt-oss-20b-fft-fsdp2-offload.yaml

@@ -44,7 +44,6 @@ learning_rate: 2e-5
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

examples/gpt-oss/gpt-oss-20b-fft-fsdp2.yaml

@@ -43,7 +43,6 @@ learning_rate: 2e-5
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

examples/gpt-oss/gpt-oss-20b-sft-lora-singlegpu.yaml

@@ -56,7 +56,6 @@ learning_rate: 2e-4
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

examples/gpt-oss/gpt-oss-safeguard-20b-sft-lora-singlegpu.yaml

@@ -56,7 +56,6 @@ learning_rate: 2e-4
 bf16: true
 tf32: true
 
-attn_implementation: flash_attention_2
 attn_implementation: kernels-community/vllm-flash-attn3  # this is not needed if using flash_attn >= 2.8.3
 
 gradient_checkpointing: true

tests/test_attn_implementation.py

@@ -9,6 +9,9 @@ Covers the Phase 1 contract:
 Plus Phase 2 gap fixes and full-model validation behaviour.
 """
 
+import logging
+from contextlib import contextmanager
+
 import pytest
 
 from axolotl.utils.config import validate_config
@@ -22,6 +25,25 @@ from axolotl.utils.schemas.enums import (
 )
 
 
+@contextmanager
+def _capture_axolotl_warnings(caplog):
+    """Capture WARNINGs from `axolotl.*` loggers via caplog.
+
+    `axolotl.cli` calls `configure_logging()` at import time, which sets
+    `propagate=False` on the `axolotl` logger so records do not reach the root
+    logger that pytest's `caplog` hooks. This helper temporarily re-enables
+    propagation for the duration of the block.
+    """
+    ax_logger = logging.getLogger("axolotl")
+    old_propagate = ax_logger.propagate
+    ax_logger.propagate = True
+    try:
+        with caplog.at_level(logging.WARNING, logger="axolotl"):
+            yield
+    finally:
+        ax_logger.propagate = old_propagate
+
+
 class TestNormalizerLegacyMapping:
     """Legacy boolean flags map to canonical attn_implementation."""
 
@@ -361,41 +383,35 @@ class TestPhase2GapFixes:
     """Regression tests for the validator gaps closed in Phase 2."""
 
     def test_sample_packing_with_eager_warns(self, min_base_cfg, caplog):
-        import logging
-
         cfg = min_base_cfg | DictDefault(
             attn_implementation="eager", sample_packing=True
         )
-        with caplog.at_level(logging.WARNING):
+        with _capture_axolotl_warnings(caplog):
             validate_config(cfg)
         assert any(
-            "does not handle cross-sample decontamination" in r.message
+            "does not handle cross-sample decontamination" in r.getMessage()
             for r in caplog.records
         )
 
     def test_sample_packing_with_sdpa_warns(self, min_base_cfg, caplog):
-        import logging
-
         cfg = min_base_cfg | DictDefault(
             attn_implementation="sdpa", sample_packing=True
         )
-        with caplog.at_level(logging.WARNING):
+        with _capture_axolotl_warnings(caplog):
             validate_config(cfg)
         assert any(
-            "does not handle cross-sample decontamination" in r.message
+            "does not handle cross-sample decontamination" in r.getMessage()
             for r in caplog.records
         )
 
     def test_sample_packing_with_flash_does_not_warn(self, min_base_cfg, caplog):
-        import logging
-
         cfg = min_base_cfg | DictDefault(
             attn_implementation="flash_attention_2", sample_packing=True
         )
-        with caplog.at_level(logging.WARNING):
+        with _capture_axolotl_warnings(caplog):
             validate_config(cfg)
         assert not any(
-            "does not handle cross-sample decontamination" in r.message
+            "does not handle cross-sample decontamination" in r.getMessage()
             for r in caplog.records
         )